BTHP vs. AMax

[ar15barrels]

At least I don't see any fault in trying to understand it so I can determine if there might be a better barrel over another to purchase.

Given similar quality bore, the thicker and longer, the better.

[micro911]

In my gas guns, I shoot 175 grain BTHP as the maximum weight. In bolt guns, if the twist is right, heavier bullets up to 220 grain BTHP will be good. The bullet design may not be as critical. Many champion shooters used Sierra and Berger BTHP bullets to win matches.

[LynnJr]

Liber
With the 168 Sierra the bullet was designed for 300 meter international match shooting and on the older boxes that is how they were labeled.
Those bullets work great until they slow down.
As bullets slow down from supersonic flight to subsonic flight they go through the transonic and if the design doesn't like it the bullet will lose stability.
The transonic is a velocity were this destabilization occurs regardless of the cartridge being used.
If you were to shoot the 168 in a 30-06 the same thing will happen but it might be at a longer distance if the load has more velocity.
As you go up in altitude the air gets thinner and your loads shoot better because there is less influence on the bullet from the atmosphere.
At our 2000 yard and beyond matches most of the bullets are subsonic when they hit the gong but we shoot bullets known to pass through the speed of sound without getting disrupted.
If your shooting a 308 look at the JBM Ballistics website and put in all the data for were you plan on shooting. Now go back and increase the velocity so your rounds are above 1175 fps at the distance you plan on shooting. If your not at or above 1200 fps start adding barrel length until you are then determine if it makes sense to use it.
28-30 inches not a big deal 46 inches forget about it and pick a different bullet.

[JMP]

I'm just wanting to understand the big picture and how it relates to what I do have.

I appreciate the help you've offered in explaining some of the process, as I do others.

I could just stick my head in the sand over the issue and not worry one way or the other, it's just that I would like to know for my own sake.

To me it makes sense to understand this before I purchase another barrel. At least I don't see any fault in trying to understand it so I can determine if there might be a better barrel over another to purchase.


Sure, but that doesn't mean it doesn't apply to 308. It certainly does in the sense of the 168 SMK from what others have stated in this thread. Again, thanks for helping explain some of this.

As ar15barrels says, the longer and thicker the better. For a 308, the length is generally around 30" (IMO) where the returns stop being enough to justify the extra cost and being overly cumbersome. In fact, since 308 is no longer really intended to shoot for distance unless you are a Palma guy, I find that a 24" barrel is just fine as that'll do well in the 0-600 yards.

For bullets, the old SMKs are the most common. The 168 SMK is about the best you'll do for 300m shooting. It lacks the design for further shooting.

Personally, I am about to get out and test the new Sierra Tipped Matchking in 168 as it should be in a different league based on the BCs. If they shoot accurately, they could be a game changer in 30 cal. Midway had a very good sale on these for about $0.10 off.

Oddly, I haven't heard much in the way of feedback for these bullets so I will be trying them out in the near future.

https://www.sierrabullets.com/store/product.cfm/sn/7768/308-dia-168-gr-Tipped-MatchKing-TMK

New TMK 168
.535 @ 2050 fps and above
.521 between 2050 fps and 1650 fps
.480 @ 1650 fps and below

Old SMK 168
.462 @ 2600 fps and above
.447 between 2600 and 2100 fps
.424 between 2100 and 1600 fps
.405 @ 1600 fps and below

The TMKs are in an entirely new league if the results are favorable. Even though I am an old 168 shooter for the 300m accuracy, these are definitely worth serious consideration. The 168 TMK will be superior to the old 175 SMK for getting out to 1,000. Then, there is less of a difference between 168 and 175 SMK for the tipped versions as they carry similar design.

My observation is that they are MUCH longer than the old bullets, so having them conform to mag length in a 2.88" standard short action magazine may be an issue.

[liber]

The BC on the new TMK does look much better, for such a small improvement.

The price is not too much more than the SMKs, but it is higher.

One thing I need to consider for myself is that if I'm going to the expense to purchase a match grade 308 barrel, it might make sense to upgrade to something better, say 260 Remington. I could still swap uppers and leave the 16" barrel on the 308. While it's not a match barrel, it's still not bad out to 300 and I shoot it mostly at 200.

With a 260 Remington, everything would be the same except for the bolt and barrel I believe. That would probably be true of 6.5 Creedmoor also

I guess it all depends on how much time I want to invest in the LR platform vs. focusing my efforts on a bolt action. That I'm not sure. The LR platform is the easy way out...LOL

[JMP]

Liber, for a non - 308 go with a bolt action. Semis are inherently less accurate and brass will be a problem. There is no way around paying up for brass, and it's about $1/piece. Semis destroy brass and it's much harder to recover. Keep your semi in 308, then for long range and accuracy go to a bolt action. It's a no-brainer.

[liber]

Liber, for a non - 308 go with a bolt action. Semis are inherently less accurate and brass will be a problem. There is no way around paying up for brass, and it's about $1/piece. Semis destroy brass and it's much harder to recover. Keep your semi in 308, then for long range and accuracy go to a bolt action. It's a no-brainer.

Yeah, I'm starting to realize that about 308, but I don't mind spending a bit extra for better brass, I've been using once fired LC Match for my 308 reloads, and happy with it. It wouldn't be the end of the world to buy new Lapua brass either...

I know that I will want much more accuracy when I build a bolt action, and why I mentioned it to begin with...I know it's better suited for a bolt action. I should just avoid thinking about upgrading my 308 and just continue shooting blaster ammo out of it. It can pile up the brass, puts 'em in a nice pile at about 2 'oclock...even my RO commented on my nice pile of brass last month...LOL

I guess I'll continue to hear how inaccurate my 308 loads are in comparison to your 338...LOL No worries it's all in jest, you won't hurt my feeling one way or the other, even if I do appreciate a good caliper...

[JMP]

Yeah, I'm starting to realize that about 308, but I don't mind spending a bit extra for better brass, I've been using once fired LC Match for my 308 reloads, and happy with it. It wouldn't be the end of the world to buy new Lapua brass either...

I know that I will want much more accuracy when I build a bolt action, and why I mentioned it to begin with...I know it's better suited for a bolt action. I should just avoid thinking about upgrading my 308 and just continue shooting blaster ammo out of it. It can pile up the brass, puts 'em in a nice pile at about 2 'oclock...even my RO commented on my nice pile of brass last month...LOL

I guess I'll continue to hear how inaccurate my 308 loads are in comparison to your 338...LOL No worries it's all in jest, you won't hurt my feeling one way or the other, even if I do appreciate a good caliper...

Liber, if you buy new 308 Lapua brass, I recommend going with the new small primer ones. I will be testing this brass with some TMKs to see how it does.

My 338s are about as large as I can shoot and still maintain good accuracy at close ranges. Even so, I cannot get anywhere near the precision of a short action cartridge. However, I'd be surprised if it didn't outperform a 16" AR in even close distance accuracy. If you like the details and want to shoot accurately and/or far, you will see that a bolt rifle is pretty much a necessity for this. If you are loading semis, or using a progressive machine, you do not need to be nearly as careful for results. You will soon find this out when you step up to a single stage press and a bolt action rifle.

With a semi, I'd have no issue shooting once-fired brass of decent quality as long as the headstamps match. For bolts, you will want to buy either Lapua or Norma brass and track the set over the lifetime to make sure you have uniformity. They should all be fired th same amount of time. If you start with good stuff, it saves you a lot of work later.

[liber]

I will be testing this brass with some TMKs to see how it does.

I'd like to test some TMKs myself, but currently have about 500-600 168 gr BTHPs which should last me a few months.

I need to order 5.56 bullets though, and will try the TMKs on those first. Those will also go in my best barrel, so it makes sense.

If you like the details and want to shoot accurately and/or far, you will see that a bolt rifle is pretty much a necessity for this.

Oh, absolutely. I keep getting ahead of myself with the 308, and quite honestly, I don't really have a driving need to go more than 308 in accuracy at the moment, as I primarily shoot at 200 yards.

But what I mean by getting ahead of myself, which I've mentioned to you before, I plan to add .45ACP to my Dillon setup next, and upgrading the 308 and/or starting the bolt action will only distract me. The 45ACP makes the most sense to compliment my current calibers.

With a semi, I'd have no issue shooting once-fired brass of decent quality as long as the headstamps match.

I don't, and at $0.25-$0.30/ea it doesn't break the bank. I like the LC Match brass I've been using. For that matter new Lapua wouldn't break the bank either, since 308 is not nearly as pricey as Lapua 338 Mag, as an example.

I was looking earlier and the BTHP and AMAX are very close in BC, but the TMK is substantially higher. I think it's like .462, .475 and .535 respectively for 168 gr.

[JMP]

I'd like to test some TMKs myself, but currently have about 500-600 168 gr BTHPs which should last me a few months.

I need to order 5.56 bullets though, and will try the TMKs on those first. Those will also go in my best barrel, so it makes sense.



Oh, absolutely. I keep getting ahead of myself with the 308, and quite honestly, I don't really have a driving need to go more than 308 in accuracy at the moment, as I primarily shoot at 200 yards.

But what I mean by getting ahead of myself, which I've mentioned to you before, I plan to add .45ACP to my Dillon setup next, and upgrading the 308 and/or starting the bolt action will only distract me. The 45ACP makes the most sense to compliment my current calibers.



I don't, and at $0.25-$0.30/ea it doesn't break the bank. I like the LC Match brass I've been using. For that matter new Lapua wouldn't break the bank either, since 308 is not nearly as pricey as Lapua 338 Mag, as an example.

I was looking earlier and the BTHP and AMAX are very close in BC, but the TMK is substantially higher. I think it's like .462, .475 and .535 respectively for 168 gr.

Liber, I got 1000 168 TMKs when they were on sale for $0.30 each. I will be testing them on small primer Lapua brass to see how they work. They will not be good in AR-15 magazines as the longest short action magazines are 2.88". My 308 already has a short throat, so I load my old 168s at 2.800 and it puts me about 0.030" from the lands. With the same chamber, 2.88" is still pretty far off the lands. These may need no-throat or to be single fed for maximum results.

Unless you are trying to get maximum distance, there is no reason that you would not use the old 168 SMK for shooting 308. There is not a bullet in the world that I can get to shoot more accurately than the 168gr SMK. However, this is for shooting to 500m or inside. That's why folks like the 155 palma type bullets of 175 SMK as it lets them shoot better at the long range of 308. If you use the 308 the way it is intended, you will see that the old 168 SMK is the way to go as they are basically impossible to mess up.

I do not use Hornady bullets as they simply lack the tolerances. Sierra is not perfect, but the weights are fairly consistent (inside of 0.4gr). If you uniform the tips, you are in business. I do nothing to the 168s and they shoot fine. With Hornady, you will find that the weights and geometry is all over the place and since they have the ballistic tip, there isn't much you can do to rectify this. This is why accurate shooters tend to not use Hornady bullets. They are more for economy shooting as they tend to be lower in price.

Just forget about the A-Max and step up to a better bullet. Then, with a Dillon, it makes sense to load 45. With 45, there isn't much to getting a decent load as it is very forgiving. Once you get your 45 ACP load down and crank out about 10,000 of them, you can get yourself a single stage press and a bolt rifle in 6 or 6.5mm and then get accuracy and more distance. You may finally get to put your nice calipers to a worthy use.

If you are already a 308 shooter with an AR-10, then go with a 6 Dasher, 260 Remington Ackley Improved, or simply step up to the 338 Lapua family, and you will have less restrictions on distance. Also, don't get a 16" barrel. Go 30".

[liber]

You may finally get to put your nice calipers to a worthy use.

LOL...they get used all the time, for much more than measuring cases.

Every time I use them I know the quality of the tool, how they feel as they roll on the slide, how they measure. It is the very reason I despise HF.

I did see someone quote that HF product comes with a lunchtime guarantee...hehehe

If you are already a 308 shooter with an AR-10, then go with a 6 Dasher, 260 Remington Ackley Improved, or simply step up to the 338 Lapua family, and you will have less restrictions on distance. Also, don't get a 16" barrel. Go 30".

I don't know if I'll go 30", but certainly in the mid to upper 20s at minimum.

I have time, no rush...in the meantime the LR-308 is bangin' 'em out...as-is the 5.56...but yeah, the idea is to get a better caliber when I build my bolt. 6mmBR has a nice benefit in regard to barrel life...not that it matters, there's always more barrels...

I'm happy with the SMKs, I haven't tried Hornady bullets, but have some Noslers I got recently. I want to try the TMKs just because they are a better bullet (higher BC) and ONLY marginally higher in price. It is such a small margin, it doesn't matter to me. My curiosity is worth more.

[Fjold]

Use the bullet that gives you the best accuracy in your bench testing with as small a variation in velocity as possible.

[liber]

Use the bullet that gives you the best accuracy in your bench testing with as small a variation in velocity as possible.

Absolutely! I plan to get some TMKs so I can do just that!

[JMP]

6mmBR has a nice benefit in regard to barrel life...not that it matters, there's always more barrels...

The 6 Norma BR is a fantastic case. With just 30gr of Varget, it will crush the 308 in every way and is good to 1km. The one issue you will have is to make sure you have magazines that feed them. On mine, they take some alteration to get them to feed as the case is very short. Then, you absolutely want a bolt with a small firing pin and firing pin hole; otherwise, you will be piercing primers as you work up.

[liber]

The 6 Norma BR is a fantastic case. With just 30gr of Varget, it will crush the 308 in every way and is good to 1km. The one issue you will have is to make sure you have magazines that feed them. On mine, they take some alteration to get them to feed as the case is very short. Then, you absolutely want a bolt with a small firing pin and firing pin hole; otherwise, you will be piercing primers as you work up.

What size is the boltface on that? I will need to get one ordered at some point from PTG.

.470 is this link is right: http://www.longrangehunting.com/foru...ameters-36661/

That must use the same size as the 308 and 260 Rem.

What is confusing is that PTG sells a standard boltface at .484, that must be for that family of calibers.