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Bungi
05-19-2012, 9:20 PM
I have a 30 inch barrel on my new Savage FTR.

I will be shooting Federal Gold Medal Match 168 gr BTHP

Anyone know what the muzzle velocity will be out of the 30 inch barrel?

rksimple
05-19-2012, 9:30 PM
Shoot it at distance and see. It will depend on a number of variables.

If you plan on shooting 1k+, get the 175gr stuff. Better yet, learn how to reload.

Chontkleer
05-19-2012, 9:35 PM
Nope. According to this, it should be about 2,762.

http://www.calguns.net/calgunforum/showthread.php?t=201149

But according to this, it should be about 2660.

http://www.tacticaloperations.com/SWATbarrel/

Tactical Operations builds 1/4 moa rifles and definitely know their stuff. Per the article, longer barrels help with hotter loads and slower-burning powder.

707electrician
05-19-2012, 10:10 PM
Depends what you are shooting. The 168's should do just fine at 1k. You could try the 175's but they wont be as fast. I would try the 155's

sigstroker
05-19-2012, 10:55 PM
Find out for sure:

http://airgunbuyer.com/ecommerce/small/access300/f1chrony.jpg

BigNick
05-20-2012, 2:19 AM
For 1k yds I would go with a heavier bullet.

AlliedArmory
05-20-2012, 4:17 AM
Not sure about the exact velocity as we only chrono reloads. But for 1k shooting I would definitely use 175gr bullets or higher or use 155gr and have them screaming. Of course that will burn your barrel super fast.

scotty99
05-20-2012, 6:11 AM
That load chronos right around 2670 out of my 24" barrel. A 30" will get you a little higher but I would not think as much as 100 FPS. It is the most accurate factory load I have tested.

As for all this talk about needing 175gr bullets for 1M yard shooting, if you were someone for whom that 7gr of weight and slightly improved BC would matter, you would not be asking velocity questions on a public forum. The 168s will shoot better at 1M than 99.8% of people are capable of anyway.

rksimple
05-20-2012, 8:26 AM
The 168's should do just fine at 1k.

Depending on the DA, no, they won't.

rksimple
05-20-2012, 8:31 AM
The 168s will shoot better at 1M than 99.8% of people are capable of anyway.

Doesn't seem like you've spent any time at 1k in 1k to -1k DA conditions.

The difference in BC between the 168 and 175 SMK is significant. One will make nice holes at 1k, the other will be sideways.

phish
05-20-2012, 10:34 AM
you've got a 1:10 barrel, go big, go 185gr Berger hybrids !

wooger
05-20-2012, 10:44 AM
168 smk's are not preferred on the long lines.

DirtRacer151
05-20-2012, 11:02 AM
Find out for sure:

http://airgunbuyer.com/ecommerce/small/access300/f1chrony.jpg

Not true at all. A chrono is never as close as the real thing. Chronos are good for load comparisons DURING THE SAME SHOOTING SESSIONS ONLY!!

Shoot it to distance, enter the known bullet BC, enter the atmospheric conditions at the time of the shot, now enter the velocity and adjust until it matches your actual dope. Save the velocity and the BC and change your atmosphere each time you shoot and you'll be good to go. %100 guaranteed to be more accurate at finding actual FPS then any chrono.

BTW 175 smk or 155 lapua scenar or sierra palma (2156). Don't waste your time on 168s or standard sierra 155s (2155)

707electrician
05-20-2012, 11:31 AM
BTW 175 smk or 155 lapua scenar or sierra palma (2156). Don't waste your time on 168s or standard sierra 155s (2155)

Yes, the sierra palmas, that is what I was talking about. I've never actually used the 168's but I can tell you that the 175s and the 155 palmas work well, the 155's probably more so if you have calm wind

Richard Erichsen
05-20-2012, 6:30 PM
I have a 30 inch barrel on my new Savage FTR.

I will be shooting Federal Gold Medal Match 168 gr BTHP

Anyone know what the muzzle velocity will be out of the 30 inch barrel?

Peak velocity for commercial .308 is usually in the 24-26" range. Beyond that it will be negligible.

R

Bungi
05-20-2012, 9:32 PM
Thanks for all of the responses.

For the sake of clarification, I am obviously not ready to attempt 1000 yard shots (maybe one day). I am also not reloading yet (probably soon).

For now, I will simply be using the Federal Gold Medal Match 168 gr & I was just trying to get a good idea regarding the expected muzzle velocity out of the 30 inch barrel on my new Savage. I expect "Richard Erichson" is correct and there is probably not much of a difference in velocity between a 30" and a 26" barrel.

707electrician
05-20-2012, 9:51 PM
Try the federal GMM with the 175 smk

brando
05-20-2012, 11:04 PM
Peak velocity for commercial .308 is usually in the 24-26" range. Beyond that it will be negligible.

^^^This

30" is serious overkill for a .308WIN. That length is normally required for cartridges that require high velocities for performance (.284 Sheehane) or big bore rifles (.375CT and .50BMG).

sigstroker
05-21-2012, 12:30 AM
Not true at all. A chrono is never as close as the real thing. Chronos are good for load comparisons DURING THE SAME SHOOTING SESSIONS ONLY!!

Shoot it to distance, enter the known bullet BC, enter the atmospheric conditions at the time of the shot, now enter the velocity and adjust until it matches your actual dope. Save the velocity and the BC and change your atmosphere each time you shoot and you'll be good to go. %100 guaranteed to be more accurate at finding actual FPS then any chrono.

BTW 175 smk or 155 lapua scenar or sierra palma (2156). Don't waste your time on 168s or standard sierra 155s (2155)

Wat? FPS is FPS. Your way is just a guess. My way uses an electronic instrument.

rksimple
05-21-2012, 7:36 AM
Wat? FPS is FPS. Your way is just a guess. My way uses an electronic instrument.

His way is far more accurate than your electronic instrument. I've shot over many, many chronos. They all lie.

Inside of 600 yards (which is as far as many people go), you could be 50 fps off and still get the same dope. That's why they think their chrono is accurate. Take it out to 1k+ and you'll see that its not telling the truth.

DirtRacer151
05-21-2012, 7:46 AM
Wat? FPS is FPS. Your way is just a guess. My way uses an electronic instrument.

Your electronic instrument is flawed. My way is part of collecting DOPE (Data Observed on Prior Engagements) its not a guess. Using the numbers posted on the ammo box is a guess.

Ever notice when you shoot through a chrono from day to day that the same load will give different readings? This could be due to the ammount of sun available at to time or a bunch of other variables.

Only time I use a chrono is when comparing loads. But the comparison must be done at the same time as tomorrow or even an hour later the reading might be different. A chrono will tell me A load is slower then B load but faster then C at best. The MV it spits out is usually inaccurate but is fairly consistent for comparison purposes. Tomorrow all 3 loads might be going 50fps faster but load B would still be fastest followed by A and C.

Shoot 3 rounds through a chrono. Take the average and enter it in your ballistic software for a 1000yd shot. You must have the bullets BC, the atmospheric conditions, and the predicted velocity. It isn't uncommon for chronos to be off by 25-100fps from day to day of actual MV. See if you hit.

Or-

Take 3 shots at 1000yds, record the actual drop you dialed with your scope, do the math backwards in your ballistics software by adjusting the MV to match with your DOPE. The atmosphere and bullets BCs are fixed numbers at the time. If the MV is adjusted to match your DOPE then you'll save that MV and use it all the time. The only thing that changes next time is atmosphere since it should be the only thing thats fluctuating.

Remember that 10fps can make the difference between a hit or miss at 1k.

I haven't relied on a chrono to give me accurate velocity numbers in almost 2 years. They hardly ever produce accurate numbers anyway.

Budd
05-21-2012, 8:05 AM
Since you are not reloading yet - try some Black Hills match 175gr bullets. That way you can save the brass as it is good brass - Federal is not - too soft.

Just my opinion.

Hoop
05-21-2012, 10:35 AM
If you have a 30" barrel why not try 155 grain palma bullets?

Also give serious consideration to a reloading setup. You can get going for a couple hundred bucks w/used stuff off ebay and it pays for itself believe me.

scotty99
05-22-2012, 7:55 AM
Doesn't seem like you've spent any time at 1k in 1k to -1k DA conditions.

The difference in BC between the 168 and 175 SMK is significant. One will make nice holes at 1k, the other will be sideways.

I'm curious why you think the 168 will be sideways at 1K. At the same starting velocity, there is only 90fps difference in velocity between these two bullets at 1K, and both are still supersonic. "Sideways" in my mind means the round has gone transonic.

My point anyway was not that the 175 is not a better 1K yard round, but rather that if the OP was someone for whom the difference between these two bullets would matter, he would not have asked the question in the first place.

rksimple
05-22-2012, 9:32 AM
I'm curious why you think the 168 will be sideways at 1K.

Because I've seen it happen NUMEROUS times. 90 fps can be the difference between supersonic and subsonic. Under certain atmospheric conditions and launch velocities, even the 175 isn't going to make it to 1k supersonic. Make sure you understand how atmospheric conditions affect the bullet and the speed of sound. That's why I made reference to specific DA's.

BIRDHUNTER757
05-22-2012, 12:02 PM
Maybe I can shed some light on the subject?

First some definitions:

Sonic=Mach 1.0 = 1116fps

Subsonic= <Mach 1.0

Transonic= Mach 0.8 - 1.2 =893fps to 1116fps

Supersonic= You guessed it Mach 1.2 - Mach 5.0 = 1340fps - 5582fps

What does this mean? Some bullets because of their boat tail design transit the transonic region better than others. i.e. the 175SMK vs. the 168smk. The current belief is the the BT angle of the 168 is the cause of it's instability during this phase.

As an object approaches and passes through the transonic region a shock wave develops causing drag and air separation nose to rear. Once above Mach 1.2 its smooth sailing. A bullet because it leaves the rifle barrel, in most cases, supersonic, does not have to worry about the acceleration stage. The problem occurs when it slows, the reverse happens, the wave moves across the projectile back to front. It is during this phase of the transition when the 168SMK starts to wobble and become unstable and sometimes tumble. The 175SMK because of its design does not have this problem. It is very stable through this region and one of many reasons why it is so favored by shooters.

So in my opinion if you are going to shoot the 168SMK effectively it needs to reach the target at or above 1330fps. Don't get me wrong, the 168SMK is a great bullet, you just have to know its limitations. Its a great round from 100 to 600 yards and sometimes 7 maybe 800yards but beyond that is a crap shoot.

Hope this helps?:)

DirtRacer151
05-22-2012, 12:35 PM
Good explanation ^

It should also be noted just like rksimple was saying that just because a 168 will make it to 1k today.. doesn't mean it will tomorrow. Atmosphere plays a big part and since 1k is such a stretch for the 168, it usually is sideways at 1k unless conditions are favorable. I about crapped myself the first time I was pulling pits and saw the guys shooting 168s going sideways through targets. Totally different sound as they go over your head as well.

The 168 is an excellent 100-600yd bullet. Probably more accurate on average then 175s through most rifles. 175s aren't far off though and make it all the way to the targets I aim at :)

Chontkleer
05-22-2012, 1:13 PM
Maybe I can shed some light on the subject?

First some definitions:

Sonic=Mach 1.0 = 1116fps

Subsonic= <Mach 1.0

Transonic= Mach 0.8 - 1.2 =893fps to 1116fps

Supersonic= You guessed it Mach 1.2 - Mach 5.0 = 1340fps - 5582fps

What does this mean? Some bullets because of their boat tail design transit the transonic region better than others. i.e. the 175SMK vs. the 168smk. The current belief is the the BT angle of the 168 is the cause of it's instability during this phase.

As an object approaches and passes through the transonic region a shock wave develops causing drag and air separation nose to rear. Once above Mach 1.2 its smooth sailing. A bullet because it leaves the rifle barrel, in most cases, supersonic, does not have to worry about the acceleration stage. The problem occurs when it slows, the reverse happens, the wave moves across the projectile back to front. It is during this phase of the transition when the 168SMK starts to wobble and become unstable and sometimes tumble. The 175SMK because of its design does not have this problem. It is very stable through this region and one of many reasons why it is so favored by shooters.

So in my opinion if you are going to shoot the 168SMK effectively it needs to reach the target at or above 1330fps. Don't get me wrong, the 168SMK is a great bullet, you just have to know its limitations. Its a great round from 100 to 600 yards and sometimes 7 maybe 800yards but beyond that is a crap shoot.

Hope this helps?:)

You probably know it, but it needs to be said that supersonic is not constant; it varies with air temperature and pressure.

"One very important consideration for bullet selection in a service rifle is velocity. With the shorter barrels and reduced pressures, itís quite a challenge to get the bullet fast enough that it stays supersonic at 1000 yards. Table 6 shows the remaining velocity at 1000 yards for each of the target bullets considered. As stated above for the Palma rifle, you want your bullets to arrive at the target at a speed thatís faster than the speed of sound which is ~1120 fps depending on temperature. You actually want to stay a little above the exact speed of sound because the negative effects of transonic aerodynamics begin to take their toll as you slow down into the transonic flight region which is faster than 1120 fps. Itís a good rule of thumb to try and stay above 1200 fps in order to avoid the worst of the transonic effects. Table 6 shows that staying above 1200 fps is a challenge for most 30 caliber bullets from service rifles. Bullets that weigh 175 grains or more have the best chance despite their lower muzzle velocities. The velocities in Table 6 are based on standard sea level atmospheric conditions. The retained velocity will be improved if youíre shooting at some altitude above sea level, and/or the air temperature is greater than 59 degrees. For example, if the air temperature is 80 degrees and youíre shooting at sea level, you can add about 30 to 35 fps to the retained velocity at 1000 yards."

http://www.bergerbullets.com/Cartridges/30%20Cal/308%20Win/308%20Win%20-%20Target.html

B!ngo
05-22-2012, 1:27 PM
Before I got to the post below, I was going to add the same, but in the form of a question. That is, 'What is the point of negative returns for a typical .308 barrel?'. At some point the powder burn rate slows enough to stop any further acceleration of the bullet, and then barrel drags takes over, slowing down the round before it exits. I have read numerous times that the .308 is typically loaded with fast-burning powder lending value to a shorter length barrel. Something like 24-26" as quoted below.
So is this 30" barrel too long for factory loads?
Just trying to learn more because I ordered a .308 with a 24" barrel.
B

Peak velocity for commercial .308 is usually in the 24-26" range. Beyond that it will be negligible.

R

Chontkleer
05-22-2012, 2:29 PM
Before I got to the post below, I was going to add the same, but in the form of a question. That is, 'What is the point of negative returns for a typical .308 barrel?'. At some point the powder burn rate slows enough to stop any further acceleration of the bullet, and then barrel drags takes over, slowing down the round before it exits. I have read numerous times that the .308 is typically loaded with fast-burning powder lending value to a shorter length barrel. Something like 24-26" as quoted below.
So is this 30" barrel too long for factory loads?
Just trying to learn more because I ordered a .308 with a 24" barrel.
B

Did you read the article above about what Tango Ops did? They cut a barrel down incrementally to 18". They saw no significant loss of velocity down to 20" and then just a little from 20" to 18". The consensus seems to be that the shorter stiffer barrel is more accurate too as you don't have long spindly barrel whipping around.

DirtRacer151
05-22-2012, 2:54 PM
Did you read the article above about what Tango Ops did? They cut a barrel down incrementally to 18". They saw no significant loss of velocity down to 20" and then just a little from 20" to 18". The consensus seems to be that the shorter stiffer barrel is more accurate too as you don't have long spindly barrel whipping around.

I've seen plenty of 26" 308s with long spindly barrels shooting .5" groups and running a little faster at 1k.

I cut my 308 to 22" and was pleased with the results.
My 16" LMT MWS can make it to 1k but its a dog. 22-24" would be preferred in a 308 for me.

I wouldn't cut a 260 built for long range shorter then 24" and a 243 shorter then 26". That's just me though.

phish
05-22-2012, 2:56 PM
The consensus seems to be that the shorter stiffer barrel is more accurate too as you don't have long spindly barrel whipping around.

this bit of academic dogma is rendered moot for reloaders

http://img.tapatalk.com/4b12fd1b-0add-1b70.jpg

32" shoots just fine at 800 yards

winxp_man
05-22-2012, 3:36 PM
Out of that 30" barrel the Op can get some ridiculous velocities with the 175 SMK. I can get 2650 average in a 20" barrel with 43.5gr of XBR 8208. There is no way I would shoot the 168 being the 175 will out preform it at 1000.

707electrician
05-22-2012, 4:17 PM
Did you read the article above about what Tango Ops did? They cut a barrel down incrementally to 18". They saw no significant loss of velocity down to 20" and then just a little from 20" to 18". The consensus seems to be that the shorter stiffer barrel is more accurate too as you don't have long spindly barrel whipping around.

Take a stubby barreled .308 to the 1000 yard line and see how accurate it is

captbilly
05-22-2012, 4:51 PM
The method you describe is likely to give you very good info for setting up your next shot but is not necessarily going to give you good muzzle velocity data. The problem is that BCs are, at best, good through narrow ranges of muzzle velocity and, at worst, a complete stab in the dark by the manufacturer, often purposely inflated to make the bullet look good. BC will vary with mach number, density, humidity, airspeed, spin rate, etc. so you can't use the BC to work back to a true muzzle velocity.

However, by using your method you are likely to come up with settings for your software that you can use to make appropriate adjustments to your scope and get hits, and that is what you are probably after. Essentially what you need to do is to find settings for your software that result in the bullet landing where the software says it will land. If you have good data on muzzle velocity, BC, wind, density, etc., and the software model is good then the bullet will hit where predicted. If any of the data you are using is incorrect, or the mathematical model is off then you won't get first shot hits. But if you back feed your data (in your case, muzzle velocity) to get the software to match the hits then you will have corrected for all other errors (data or model). The problem is that your back fed muzzle velocity is likely not going to work at ranges very different than the one you used to establish the muzzle velocity because the calculations used (inside the software) are still using inaccurate BCs and potentially other data that is inaccurate.

A good chrono is likely to be accurate to a level that is much better than your ability to load ammo. In other words, the variation from one round to the next is likely to be much larger than the inaccuracy in the muzzle velocity from a good chrono. Of course many chronos aren't very good, for the reasons you mentioned, so you need to understand the limitiations and work to insure that you use your chrono in a way that gives accurate info. Then you can backfeed BC data to get your software to properly predict impact point. Either way you are going to have to do something to get the actual impact point to match the predicted.

Your electronic instrument is flawed. My way is part of collecting DOPE (Data Observed on Prior Engagements) its not a guess. Using the numbers posted on the ammo box is a guess.

Ever notice when you shoot through a chrono from day to day that the same load will give different readings? This could be due to the ammount of sun available at to time or a bunch of other variables.

Only time I use a chrono is when comparing loads. But the comparison must be done at the same time as tomorrow or even an hour later the reading might be different. A chrono will tell me A load is slower then B load but faster then C at best. The MV it spits out is usually inaccurate but is fairly consistent for comparison purposes. Tomorrow all 3 loads might be going 50fps faster but load B would still be fastest followed by A and C.

Shoot 3 rounds through a chrono. Take the average and enter it in your ballistic software for a 1000yd shot. You must have the bullets BC, the atmospheric conditions, and the predicted velocity. It isn't uncommon for chronos to be off by 25-100fps from day to day of actual MV. See if you hit.

Or-

Take 3 shots at 1000yds, record the actual drop you dialed with your scope, do the math backwards in your ballistics software by adjusting the MV to match with your DOPE. The atmosphere and bullets BCs are fixed numbers at the time. If the MV is adjusted to match your DOPE then you'll save that MV and use it all the time. The only thing that changes next time is atmosphere since it should be the only thing thats fluctuating.

Remember that 10fps can make the difference between a hit or miss at 1k.

I haven't relied on a chrono to give me accurate velocity numbers in almost 2 years. They hardly ever produce accurate numbers anyway.

rksimple
05-22-2012, 5:48 PM
The method you describe is likely to give you very good info for setting up your next shot but is not necessarily going to give you good muzzle velocity data. The problem is that BCs are, at best, good through narrow ranges of muzzle velocity and, at worst, a complete stab in the dark by the manufacturer, often purposely inflated to make the bullet look good. BC will vary with mach number, density, humidity, airspeed, spin rate, etc. so you can't use the BC to work back to a true muzzle velocity.

However, by using your method you are likely to come up with settings for your software that you can use to make appropriate adjustments to your scope and get hits, and that is what you are probably after. Essentially what you need to do is to find settings for your software that result in the bullet landing where the software says it will land. If you have good data on muzzle velocity, BC, wind, density, etc., and the software model is good then the bullet will hit where predicted. If any of the data you are using is incorrect, or the mathematical model is off then you won't get first shot hits. But if you back feed your data (in your case, muzzle velocity) to get the software to match the hits then you will have corrected for all other errors (data or model). The problem is that your back fed muzzle velocity is likely not going to work at ranges very different than the one you used to establish the muzzle velocity because the calculations used (inside the software) are still using inaccurate BCs and potentially other data that is inaccurate.

A good chrono is likely to be accurate to a level that is much better than your ability to load ammo. In other words, the variation from one round to the next is likely to be much larger than the inaccuracy in the muzzle velocity from a good chrono. Of course many chronos aren't very good, for the reasons you mentioned, so you need to understand the limitiations and work to insure that you use your chrono in a way that gives accurate info. Then you can backfeed BC data to get your software to properly predict impact point. Either way you are going to have to do something to get the actual impact point to match the predicted.

This is simply not true. Using Litz G7 BCs (and even his published G1 data) I've consistently had far more accurate results than trusting a whole host of chronographs...from CED Millenniums to Chrony's to Pacts. Sounds like you need to get a copy of Byran Litz's book so you can have some more accurate BC data. Use a good ballistics program and learn how to tweak the variables.

I have a ProChrono that consistently runs about 60fps slow. I have a Shooting Chrony that runs about 50fps fast. Set them up together, one right in front of the other and they read over 100fps apart. I trusted a friends CED that we set up upon arriving to WA for a major match a couple months ago. I did it against my better judgment. Turns out his was running about 50 fps slow. Inside 600 yards it doesn't make much difference, but it sure explains why I sailed high over my 900 yard target. Had I trusted the dope I collected off some back roads we got the night before, I would've made a hit. My friend did the exact same thing trusting the chrono with his load as well.

We're not just talking out of our collective a**es here. I compete in tactical long range matches all over the country, in widely varied atmospheric conditions...DAs from -1000 to 10k+ft. The chrono numbers are never as accurate as obtaining real dope, meticulously recording conditions, and working backwards from there.

But feel free to advocate trusting a chrono. I don't need any extra competition in any upcoming matches.

phish
05-22-2012, 5:52 PM
If I had a nickel for every Pro-E and pSpice simulation that was an epic fail...

DirtRacer151
05-22-2012, 5:59 PM
The method you describe is likely to give you very good info for setting up your next shot but is not necessarily going to give you good muzzle velocity data. The problem is that BCs are, at best, good through narrow ranges of muzzle velocity and, at worst, a complete stab in the dark by the manufacturer, often purposely inflated to make the bullet look good. BC will vary with mach number, density, humidity, airspeed, spin rate, etc. so you can't use the BC to work back to a true muzzle velocity.

However, by using your method you are likely to come up with settings for your software that you can use to make appropriate adjustments to your scope and get hits, and that is what you are probably after. Essentially what you need to do is to find settings for your software that result in the bullet landing where the software says it will land. If you have good data on muzzle velocity, BC, wind, density, etc., and the software model is good then the bullet will hit where predicted. If any of the data you are using is incorrect, or the mathematical model is off then you won't get first shot hits. But if you back feed your data (in your case, muzzle velocity) to get the software to match the hits then you will have corrected for all other errors (data or model). The problem is that your back fed muzzle velocity is likely not going to work at ranges very different than the one you used to establish the muzzle velocity because the calculations used (inside the software) are still using inaccurate BCs and potentially other data that is inaccurate.

A good chrono is likely to be accurate to a level that is much better than your ability to load ammo. In other words, the variation from one round to the next is likely to be much larger than the inaccuracy in the muzzle velocity from a good chrono. Of course many chronos aren't very good, for the reasons you mentioned, so you need to understand the limitiations and work to insure that you use your chrono in a way that gives accurate info. Then you can backfeed BC data to get your software to properly predict impact point. Either way you are going to have to do something to get the actual impact point to match the predicted.

I'm going to have to agree and disagree at the same time.

Published BCs on boxes are usually G1. As you said they are sometimes inflated as well.
G7 on the otherhand is usually very close.

I have never once noticed any of the issues you mention while using my method. Understandably if you were using a BC that was way off then you would see those kinds of problems. I'm willing to bet most tested G7 BCs are closer in actuality then %90 of the chronos on the market.

One thing my method would cover up as well would be scope adjustment inaccuracies. Say you were running a scope last week and using DOPE determined your MV to be 2975fps on a 243. Now you put a new scope on and magically your same DOPE is 50fps slower. This could be due to the turrets not being %100 accurate. Instead of dialing .1 mil you might be dialing less in actuality. Since it now requires you to dial more clicks to effectively hit the same target, you would think your MV is much slower now. Unless you test your clicks you'd really never know though. The beauty is that it works either way.

A shooter who's click value is actually %96 of full value and accounts for it would have a MV of 2975fps and dial 7.9 mils to 1k at 1000ft DA.
A shooter who's click value is the same but doesn't know it would estimate their MV at 2925ps and still be dialing 7.9 mils to 1k.

The beauty is with a correction factor of 1.045, both shooters would still be dialing-
.4 @ 200yds
1.0 @ 300
1.7 @ 400
2.5 @ 500
3.4 @ 600
4.3 @ 700
5.4 @ 800
6.6 @ 900
.....

thats both shooters running completely different velocity numbers only one is taking the turret correction factor into consideration.

So even though you are theoretically correct coming from a G1 standpoint... a shooter who hasn't tested his equipment and/or is using G1 BCs is probably going to run into some issues down the line...guys who input accurate numbers and use G7 numbers get accurate results.

Keep buying those fancy chronos though. I'll keep sending rounds down range.

Chontkleer
05-23-2012, 2:01 AM
I've seen plenty of 26" 308s with long spindly barrels shooting .5" groups and running a little faster at 1k.

I cut my 308 to 22" and was pleased with the results.
My 16" LMT MWS can make it to 1k but its a dog. 22-24" would be preferred in a 308 for me.

I wouldn't cut a 260 built for long range shorter then 24" and a 243 shorter then 26". That's just me though.

Pleased with the results meaning you were shooting better?

I've seen .5" groups too from 26"... mine (not lately now for some reason though). Question is would you have seen .25" groups with a shorter barrel?

Chontkleer
05-23-2012, 2:12 AM
Take a stubby barreled .308 to the 1000 yard line and see how accurate it is

Have you seen it?

If this video isn't fibbing, looks like it's doing just fine (with not a lot of wind).

http://youtu.be/15qj032UJ1I

Chontkleer
05-23-2012, 2:19 AM
this bit of academic dogma is rendered moot for reloaders

http://img.tapatalk.com/4b12fd1b-0add-1b70.jpg

32" shoots just fine at 800 yards

Sure, but would 20" shoot finer?

707electrician
05-23-2012, 5:45 AM
Have you seen it?

If this video isn't fibbing, looks like it's doing just fine (with not a lot of wind).

http://youtu.be/15qj032UJ1I

I've not only seen it, I've experienced it with my 22" .308. Up to 800 yards it does fine but past that it struggles

I'm not saying it won't hit the target but how many people can clean a 1000 yard NRA target with a 20" .308

DirtRacer151
05-23-2012, 6:32 AM
Pleased with the results meaning you were shooting better?

I've seen .5" groups too from 26"... mine (not lately now for some reason though). Question is would you have seen .25" groups with a shorter barrel?

Not at all. I was pleased with the balance of handling of the rifle vs velocity lost.

I did not notice it shot any better. It was more difficult to make long shots but that's not what I built it for. I have 243s and 260s with long barrels for that.

If my only long range rifle was a 308 I'd stick with 24-26". This whole shorter is more accurate idea is dumb. You'd have to put the rifle in a vice to notice any small accuracy improvements and even then those improvements would be washed out the window at long range when your bullet is going slower and getting tossed around by the wind.

Also remember that you're essentially talking about barrel harmonics. The ability to fine tune your loads/rifle solves that problem.

rksimple
05-23-2012, 7:48 AM
Question is would you have seen .25" groups with a shorter barrel?

You need to get out and shoot more. Get some more experience with different rifles. The whole "shorter, stiffer barrel is more accurate" junk is more theory than anything. You'll see that the more barrels you go through. And spend some time at 1k in a little wind with an 18" 308. You'll experience what we're saying.

I've had custom 20 and 22" 308s that shot 3/4 moa. I've had a couple 28" 243 barrels that shot in the 3's. My current 260's are 25 and 26" and shoot in the 2's. The barrel length doesn't matter as far as inherent accuracy is concerned. Go down the line at the next Palma match at Sac Valley and tell them their rifles would be more accurate at 18" instead of 30"+. You'll get laughed out of there.

Also, take a look at OBT theory as well. Its more food for thought on barrel length.

RugerNo1
05-23-2012, 9:14 AM
Have you seen it?

If this video isn't fibbing, looks like it's doing just fine (with not a lot of wind).

http://youtu.be/15qj032UJ1I

Every time short barreled .308s get mentioned for shooting long range this video comes up. Keep in mind that Lowlight is using a short barrel AND a supressor which effectively acts as an additional few inches to the barrel. Therefore, it is not necessarily a fair comparison of an 18'' barrel versus a 22"+ barrel.

I think some people in this thread need to be taken out to conditions out of their "expertise" and shoot their stubby .308s.

P.S. The next person that talks about barrel harmonics needs to give more developement to their understanding before mearly spouting off the key words...(cue frantic Google-ing)

Short Action Precision
05-23-2012, 10:30 AM
There are a lot of couch shooters here. Rksimple, DirtRacer and Ruger are not one of those. Listen to these guys. They know what they are talking about. If you want a 308 with an 18" barrel then by all means get one. Bring it to a 1k match and see how you do. If your in that setting long enough a light bulb might go off!

Chontkleer
05-23-2012, 10:31 AM
I've not only seen it, I've experienced it with my 22" .308. Up to 800 yards it does fine but past that it struggles

I'm not saying it won't hit the target but how many people can clean a 1000 yard NRA target with a 20" .308

I dunno! I suspect the answer is "just as many as can do it with a 26" or 30" barrel" depending on rifle and load and conditions. Someone should do a shoot off with experienced shooters, everything identical except barrel length.

Chontkleer
05-23-2012, 10:42 AM
Every time short barreled .308s get mentioned for shooting long range this video comes up. Keep in mind that Lowlight is using a short barrel AND a supressor which effectively acts as an additional few inches to the barrel. Therefore, it is not necessarily a fair comparison of an 18'' barrel versus a 22"+ barrel.

I think some people in this thread need to be taken out to conditions out of their "expertise" and shoot their stubby .308s.

P.S. The next person that talks about barrel harmonics needs to give more developement to their understanding before mearly spouting off the key words...(cue frantic Google-ing)

Well not only that, but it looks like he's shooting off of his deck and as I get older that whole idea is getting more and more appealing to me.

Chontkleer
05-23-2012, 10:46 AM
There are a lot of couch shooters here. Rksimple, DirtRacer and Ruger are not one of those. Listen to these guys. They know what they are talking about. If you want a 308 with an 18" barrel then by all means get one. Bring it to a 1k match and see how you do. If your in that setting long enough a light bulb might go off!

They've got a lot of great things to say and teach. (You gotta admit it's interesting though how vigorously people defend the long barrels though!)

At a match, would we learn anything? Aren't people shooting handloads specially suited to the longer barrels?

Chontkleer
05-23-2012, 10:50 AM
You need to get out and shoot more. Get some more experience with different rifles. The whole "shorter, stiffer barrel is more accurate" junk is more theory than anything. You'll see that the more barrels you go through. And spend some time at 1k in a little wind with an 18" 308. You'll experience what we're saying.

I've had custom 20 and 22" 308s that shot 3/4 moa. I've had a couple 28" 243 barrels that shot in the 3's. My current 260's are 25 and 26" and shoot in the 2's. The barrel length doesn't matter as far as inherent accuracy is concerned. Go down the line at the next Palma match at Sac Valley and tell them their rifles would be more accurate at 18" instead of 30"+. You'll get laughed out of there.

Also, take a look at OBT theory as well. Its more food for thought on barrel length.

Shoot more -- you got that right.

Palma -- do they shoot .308?

The OBT stuff is interesting. What I understand from this: http://www.the-long-family.com/OBT_paper.htm is that there's simply an optimum for any given barrel length, which would suggest that it really doesn't matter, accuracy-wise as long as you're using a bullet/barrel combination that burns all the powder and provides enough momentum to keep a round supersonic and wind-fightery out to 1,000 yards. I've been living in the world of factory 175 gram smk's out of a 26" barrel, but the competitive long range shooters are mostly shooting bullets that perform better at long range and they're tweaking their loads for their barrel length of course. I suspect that if in fact an 18" or 20" can be more accurate, all things being equal it's due to the fact that less can happen in the time it takes the bullet to exit the barrel of a shorter barrel, resulting in smaller dispersion.

Short Action Precision
05-23-2012, 10:53 AM
I dunno! I suspect the answer is....

Someone should do a shoot off with experienced shooters, everything identical except barrel length.


This is why you should listen to these guys. They are out there actually shooting there rifles in all types of conditions and matches. Frank is shooting off a shooting tower in that video.

Short Action Precision
05-23-2012, 10:56 AM
They've got a lot of great things to say and teach. (You gotta admit it's interesting though how vigorously people defend the long barrels though!)

At a match, would we learn anything? Aren't people shooting handloads specially suited to the longer barrels?

Its people like them trying to stop the FUD and the myths that all the new guys believe will work. If you are at a match with FGMM and 175's you would see a difference with a shorter barrel. If you are not shooting Match ammo or reloads then your not going to be consistently hitting at 1k. Get out to one of the matches. Even if you get last it will be the best experience you can get.

RugerNo1
05-23-2012, 11:34 AM
They've got a lot of great things to say and teach. (You gotta admit it's interesting though how vigorously people defend the long barrels though!)

At a match, would we learn anything? Aren't people shooting handloads specially suited to the longer barrels?

At a match, shooters have their loads tuned to the particulars of the rifles they are shooting. Longer barrels also have a larger margin of safety for newer reloaders because they do not have to make such a hot load to meet their velocity needs. A load that will make 1000 yards in an 18" barrel will often be very close to over pressure (a ticking time bomb waiting for the right conditions - Murphy's Law prevails) and should only be done by experienced reloaders. A newbe could easily blow up their rifle, and perhaps themselves, by trying to duplicate someone else's short barrel load.


Shoot more -- you got that right.

Palma -- do they shoot .308?

Palma shooters use either .223 Remington or .308 Winchester at 800, 900, and 1000 yards with iron sites only. If you ever have a chance to speak with a well traveled and experienced Palma shooter, ask them questions because they are some of the most talented shooters you will ever meet. There are a couple on this board that usually chime in on these threads as well. Listen when they speak.

Chontkleer
05-23-2012, 11:38 AM
Its people like them trying to stop the FUD and the myths that all the new guys believe will work. If you are at a match with FGMM and 175's you would see a difference with a shorter barrel. If you are not shooting Match ammo or reloads then your not going to be consistently hitting at 1k. Get out to one of the matches. Even if you get last it will be the best experience you can get.

Coincidentally, there's one coming up this Sunday (maxing out at 600 at Angeles?) Unfortunately my wife doesn't share my interest in testing accuracy, so I will have to work up an optimum load to use in convincing her that I need to be out shooting a lot. :innocent:

phish
05-23-2012, 12:35 PM
Sure, but would 20" shoot finer?

don't know and don't care, I just mooch off all the dirty work that hundreds if not thousands of shooters have already done

lol@ "the video", it may make the noobs nod their heads, while the shooters just shake their heads

but by all means, feel free to do a barrel length study on your dime or set a couple of F/TR records with a 20 incher