Ballistics Mystery

[killshot44]

As a mechanical engineer, Mr Sumoba can't leave work at work. Good thing, too.

The ONLY way that the same bullet pushed by a slower charge would print higher on a target than that of a higher charge is if the trajectory is influenced by the Zero as he described.

[Flouncer]

Flouncer
If you where to use a machine rest and go from book minimum to book maximum at 100 yards most chamberings would have a vertical spread under 3.5 inches.

Yes, that was what I was trying to say back on the first page. An because he is not going from minimum to maximum loads, the discrepancy in the point of impact can't be just from the velocity difference.

[btm]

Just curious, how many of you think the rifle doesn't move until the bullet is out of the barrel?

[ar15barrels]

Just curious, how many of you think the rifle doesn't move until the bullet is out of the barrel?

I KNOW it does.

[LynnJr]

BTM
If you click on the link I posted a typical non-tuner rifle has over 16,000 nodes and with a tuner it has over 19,000 different nodes. In shooting free recoil the forend typically raises itself off of the front sandbag as well.
I would say the rifle moves before the bullet leaves the barrel as well.
You can build a rifle pendulum and make your own conclusions.

[AFTII]

Just curious, how many of you think the rifle doesn't move until the bullet is out of the barrel?

Unless you know how to set up a rifle in a rest, a typical rifle will move when the firing pin falls. It's not difficult to conceive when you realize all of the movement that occurs when you pull the trigger.

The sear disengages, the cocking lever disengages from the firing pin block (it rises as the firing pin block falls). The firing pin begins to decompress. The firing pin and firing pin spring travel down the firing pin channel in the bolt, etc. Lots of movement and all of these things equal lots of vibrational movement before the firing pin ever contacts the primer.

A good gunsmith can minimize the effects of these movements, but they effect every rifle to some extent.

[killshot44]

Oh jeebus, not the "does the bullet leave the barrel before it moves?" crap again...

[bsumoba]

BTM
If you click on the link I posted a typical non-tuner rifle has over 16,000 nodes and with a tuner it has over 19,000 different nodes. In shooting free recoil the forend typically raises itself off of the front sandbag as well.
I would say the rifle moves before the bullet leaves the barrel as well.
You can build a rifle pendulum and make your own conclusions.

Someone was asking John Meyers, a champion F-Class shooter about barrel tuners. He is one of the only guys in F-Class that figured out some sort of process such that he moves the tuner prior to a relay. For the record, I would be scared to do this. That being said, he has worked with a lot of benchrest guys on tuners and he too, mentioned that there are thousands of nodes in a barrel.

I still do not see the advantage of a tuner and have tried to convince myself to put one on. But, when I can get a gun that has a good barrel and good bullets to shoot into small groups consistently, I am not sure how much more a tuner would help at that point. Once you have a decent process to work up a load, IMO it is all barrels and bullets from there. Get a good barrel and good bullets and you will most likely have a good shooting gun.

I also am a believer that the barrel moves before the bullet exits...wait...I KNOW that the barrel moves before the bullets exit. If the barrel didn't move, then tuners and dampeners would not work...

Oh jeebus, not the "does the bullet leave the barrel before it moves?" crap again...

Maybe this started because of the pistol guys??? They always claim the bullet exits before the pistol starts to move. So, if you pull the trigger on a handgun and it is pointed at your target, you will hit your target. The problem is people that flinch or jerk the trigger, which moves the gun prior to ignition.

[LynnJr]

Bryan
If you look the numbers up a tuner will reduce a 0.600 group to 0.200 that is a very rough estimation and not the actual number.
When your distance increases you need to back off on your tuner.
To picture why take two sticks seperated by a quarter inch and put there tips together so they are touching. The tips touching represent the compensation or convergence at that distance.
If you now extend those two sticks the two shots will now seperate and that gap will widen with distance.
That isn't a problem with Benchrest as there is a practice day in between 600 and 1000 yards.
As you shoot F-Class at multiple distances you would need your "Setting" for each distance.

[ar15barrels]

Maybe this started because of the pistol guys??? They always claim the bullet exits before the pistol starts to move. So, if you pull the trigger on a handgun and it is pointed at your target, you will hit your target. The problem is people that flinch or jerk the trigger, which moves the gun prior to ignition.

Ever look a how tall the front sight is in relation to the rear sight on any revolver?
If you had a laser beam that pointed straight down the bore to the target and then looked where the sights are aimed, the two are WAY apart from each other.
This is done because the gun starts recoiling before the bullet leaves.
By the time the bullet gets out of the muzzle, the barrel is actually pointed where the person was aiming before they pulled the trigger...

[AFTII]

I worked RF Microwave for 22 years so I do know the difference.
If you follow Dr Geofrey Kolbe on his Compensation Theory it is the anti-node.
If you follow the world's best Rimfire Gunsmith Bill Calfee you want the NODE and not the anti-node at the crown of the barrel and not the typical 2.5-2.75 inches back it is routinely at.
I follow Bill Calfee because his guns win more big matches than all the other Gunsmiths combined and following his instructions I won a big match in 2010.

http://www.geoffrey-kolbe.com/articles/rimfire_accuracy/tuning_a_barrel.htm

Here is a combined article that explains what Al Harral and Dr Kolbe have to say but not what Bill Calfee has to say. Bill doesn't use the correct terminology so the engineers turn there noses up but none of them can tune a rifle like he does. When he says stopped muzzle he wants the node which looks stopped in a standing wave at the crown nothing more nothing less. If you follow his writings I am that Lynn or WaterBoy for the last 25 years.

Yea. I know you are. The fact is, we had this exact argument on 1/27/08. You were wrong then and you are still wrong eight years later.

[LynnJr]

I don't know any AFTI so who are you? Is your name Mike?
And please point out the mistake I made as all I see is me comparing the two schools of thought.
I will always fix a mistake.
1-27-08 would have been my wife's birthday so I will guess you are from southern California and shoot at Ojai am I getting warm?

[bsumoba]

Bryan
If you look the numbers up a tuner will reduce a 0.600 group to 0.200 that is a very rough estimation and not the actual number.

I know a tuner should help, but the problem I have with tuners is that if it were the greatest thing, then why are tuners not winning every match out there? Or, why aren't the ones using tuners winning day in and day out? This tells me that in my discipline, F-Class, having a gun that shoots tiny groups is not the determining factor like in benchrest. In F-Class, the gun that shoots the smallest vertical and the shooter that reads the wind the best typically win matches.

So, my answer to that is rather than putting a tuner on, I rather get a gun to shoot the best I can get it to shoot, then spend the rest of time on the firing line.

Ever look a how tall the front sight is in relation to the rear sight on any revolver?
If you had a laser beam that pointed straight down the bore to the target and then looked where the sights are aimed, the two are WAY apart from each other.
This is done because the gun starts recoiling before the bullet leaves.
By the time the bullet gets out of the muzzle, the barrel is actually pointed where the person was aiming before they pulled the trigger...

I did not know that...I thought that the sights are typically zero'd at a particular distance, say 15 or 25 yards.

In this slow motion videos below, it appears that the bullet is leaving before the handgun recoils upwards.

[diver160651]

Yea. I know you are. The fact is, we had this exact argument on 1/27/08. You were wrong then and you are still wrong eight years later.

Holly smokes... That's nuts... Not caring who is right, I don't want to remember some of the fubar stuff I did, much less have someone stalk me

I don't remember what I just had for dinner anyway.

[LynnJr]

Diver
I am thinking his name is Mike S and he is a well known Shooter from SoCal I met at a few matches in Ojai.
My late shooting buddy John Crawford knew him better than myself but a decent guy even if he is wrong about tuners and what makes them shoot.

On F-Class shooting the tuner would take the vertical out of the equation so the wind would be the problem as it always is.
On do they win the answer is yes.
Gene Bukeys has won 2 out of the last three Super Shoots which is the Superbowl of benchrest using a tuner and the smallest group ever fired in competition was done with a rifle sporting a tuner.
In Rimfire where you don't reload just about every winning gun is wearing a tuner.
Bill Calfee told all the Benchrest Shooters how he "Tunes" a rifle to get the best groups but they for the most part are crotchety old men who hate change and don't listen.