Barrel tuners or other muzzle devices effect on velocity and velocity stats

[Bill Norris]

Bill, it looks like it could be either way...Do you move the actual brake on that thing, to make tuning adjustments? If so, I can half way get my head around how it would do this but not so much, if the brake is not moveable.

The brake stays put against the self-timing nut. The tuner is the only part that moves in or out.

 

[Bill Norris]

I am familiar with it, but when you said brake I was thinking of the more common muzzle brake not Erik's combo. Once again I do not se how that would affect muzzle velocity unless you think the muzzle blast blowing on the base of the bullet could push it faster

Understand.

 

[gunsandgunsmithing]

The brake stays put against the self-timing nut. The tuner is the only part that moves in or out.

That's what I thought. Really just grasping at straws here, I think.

 

[Bill Norris]

That's what I thought. Really just grasping at straws here, I think.

Next time I'm out with one of my rifles with the tuner/brake installed I will try another set of groups at different tuner settings to see if it duplicates but I'm almost certain it will since I've seen it happen with three different rifles. The reason I say this is because I made a mental note of it when I saw it the first time and payed attention with the other two rifles.

 

[gunsandgunsmithing]

Next time I'm out with one of my rifles with the tuner/brake installed I will try another set of groups at different tuner settings to see if it duplicates but I'm almost certain it will since I've seen it happen with three different rifles. The reason I say this is because I made a mental note of it when I saw it the first time and payed attention with the other two rifles.

Yes, please do! This whole discussion implies that moving a tuner changes pressures in the bore after the bullet leaves the bore. How would that happen? If that's actually what happens, it just got above my pay grade by quite a bit. I'll have to talk about this with some engineer friends...But I thoroughly enjoy learning anything and everything I can about tuning with tuners. For now, I can't help but think we must eliminate all other possibilities first. I just can't see the correlation between pressures and harmonics. Even then, tuners don't change the actual frequency enough to alter things in this regard...I don't think.Given absolutely equal parameters, the bullet is still in the bore for x amount of time. Harmonics certainly can't affect speeds after it clears the bore, can they? I might be convinced about the pressure or shock wave creating some tiny change...Nope, nevermind. I can't yet. This will give me a headache, just thinking about what might, maybe, possibly...do this. Then we'll find out it was something simple.

 

[darkangel_r2]

if it is not affecting the velocity how could it affect the stats? I would be more concerned about how it would affect the POI, but that is just me. You shoot in low SD contests maybe?

Increasing or decreasing the velocity spread without effecting the average velocity of the load.

 

[darkangel_r2]

I have done a full powder test with 5 shots per charge with and without a tube on the end of my 308 and found SD/ES trends were different.

Same day or two different days? Did environment factors change much between these two tests?

 

[darkangel_r2]

Changing settings on my brakes on three different rifles changed the S D & E S.

Do you recall the magnitude of the change?

 

[darkangel_r2]

you mean changing the tuner settings? I have never seen or heard of a muzzle brake that is adjustable.

I have seen changes in ES/SD just by removing my jacket however. Two groups of ten rounds each all loaded at the same time and randomly pulled from the ammo box, powder measured to .02 gns on a A&D 120. Shot at 300 yards fifteen minutes apart same rifle same conditions etc. Only difference was I removed my jacket

edited for pic and explanation

Jacket? As in clothing?

 

[darkangel_r2]

Keep in mind, I've done vibration analysis testing that allowed me to see bullet exit and barrel position while moving the tuner, while reading velocities. So, I don't think it's a harmonically induced thing at all.

Is that data publicly available? I'd love to see the results of this type of experiment.

 

[darkangel_r2]

Yes, please do! This whole discussion implies that moving a tuner changes pressures in the bore after the bullet leaves the bore. How would that happen?

I don't think anyone is trying to make that argument.

I am trying to get real data and expertise from quality shooters to see if different barrel harmonics can change the ES and SDs of a load. Microscopic expansions/contractions or flexes in the barrel can be changed by adding a tuner or muzzle device. Can these make a noticeable change on the macro velocity stats of a load.

That's what I want to know.

 

[Bill Norris]

Yes Im just trying to understand it as well. One question that comes to mind is does the effect of different harmonic vibrations affect the ease or difficulty at which the bullet travels down the barrel? Maybe that's dumb but just a thought anyway.

 

[Bill Norris]

Do you recall the magnitude of the change?

Best I remember it didnt seem excessive but I really need to try it again to be more certain.

 

[darkangel_r2]

If you think about it this way: if the barrel bends the bullet bends too and more or less bearing surface is contacted. If the barrel expands and contracts due to 60000ish psi increase in the barrel and that expansion and contraction travels up and down the barrel then the grip on the bullet is increased or decreased at certain intervals. If a tuner or other muzzle device can effect the timing or magnitude of those things it may have impact on the velocity stats.

 

[Bill Norris]

Do you recall the magnitude of the change?

If you think about it this way: if the barrel bends the bullet bends too and more or less bearing surface is contacted. If the barrel expands and contracts due to 60000ish psi increase in the barrel and that expansion and contraction travels up and down the barrel then the grip on the bullet is increased or decreased at certain intervals. If a tuner or other muzzle device can effect the timing or magnitude of those things it may have impact on the velocity stats.

Right this is where my tiny brain cell went. Maybe we could get some other members to check it with their rifles with tuner/brakes installed and see what they find as well.

 

[darkangel_r2]

Best I remember it didnt seem excessive but I really need to try it again to be more certain.

If you do that test again please post the results here. I don't have a tuner and the only barrel I have thats threaded are ar15s and an ar10. I doubt my loads for those have a low enough SDs to reliably mark the changes a tuner would produce.

 

[Bill Norris]

If you do that test again please post the results here. I don't have a tuner and the only barrel I have thats threaded are ar15s and an ar10. I doubt my loads for those have a low enough SDs to reliably mark the changes a tuner would produce.

I definitely will do it over first chance I get and post my results and would like to see others results as well.

 

[TQB]

I don't know if this helps or not, but here is some data about this subject from Bryan Zolnikov.

 

[darkangel_r2]

I don't know if this helps or not, but here is some data about this subject from Bryan Zolnikov.

Probably not enough shots at each tune setting to know for sure if its the setting or just variations natural to the load. But its good to see someone is posting data like this. I'll look through his video library and see if there is anything more.

 

[Bill Norris]

I don't know if this helps or not, but here is some data about this subject from Bryan Zolnikov.

Very interesting no doubt. Hoping Erik Cortina will have time to chime in and give us his thoughts on the subject.