Effects of Sound Suppressors on Muzzle Velocity, Bullet Yaw, and Drag

[THEIS]

Hi,

Figured this might be of interest to some of our ELR members here...especially with @Jim Boatright advising of the concerns and potential accuracy degradation from certain types of muzzle brakes.

Effects of Sound Suppressors on Muzzle Velocity, Bullet Yaw, and Drag

Sincerely,
Theis

 

[TripleBull]

Thank you, Theis. It would be interesting to see the results with solids as a function of spin rate.

 

[lash]

This ties into Jim Boatright's writing about barrel and brake induced yaw. But it also seems to indicate that the proper suppressor could be combined with a faster twist rate when shooting solids to further enhance initial yaw reduction. The paper and study is food for thought but leaves a lot wanting in my estimation. First there needs to be more studies of larger samplings to reproduce the results. Second, this study seems very much like it was done largely to promote the two-stage symmetric suppressor design by some of the authors vs. another (well recognized) name brand suppressor of the mouse hole/K-baffle design. The suppressor manufacturer sponsored, set-up and supported the whole study resulting in this paper.

Please don't get me wrong by thinking that I am calling into question the results of the study. I have not seen any of the data nor the raw results, nor do I wish to call into question the integrity of the authors. I do not know them nor have I honestly heard of them. I am nobody as far as that goes. I am just saying that further independent substantiation and more in-depth studies could help to solidify this as science.

I am well aware that studies funded, conducted, sponsored or otherwise driven by industry are the beginning of many good things and very much the drivers of our current knowledge on many, many subjects (if not most). So I hope that my tone doesn't come off wrong. Anecdotally, I've found my .260 to shoot much tighter at all distances with my 9" can on it than without. After reading this, I feel that I need to hurry up and complete my paperwork to get my .338 can out from purgatory so that I can see about reducing the short range yaw I experience using my solids. If it holds true, It should also improve things at all distances.

 

[LastShot300]

Great info, thanks Theis

 

[towerofpower93]

I was initially suspect as well, when I saw the unknown suppressor manufacturer was part of the test, but the testing parameters seem to fairly sound.

I've never developed suppressed and unsuppressed loads in a rifle accurate enough to tell the difference, but this has me thinking about doing it just for the sake of data collection. My 77gr .223 AR loads hold the same .8 groups with or without the can, but environmentals make it hard to do a suppressed/unsuppressed test with the same conditions at distance to see if the can is inducing yaw. I also have a FH suppressor mount on the upper, so the test wouldn't be as useful as suppressor on vs a bare muzzle.

 

[THEIS]

Hi,

Here is entity that conducted test. Might want to check their resume and current projects ?

http://www.btgresearch.org

Edited to add: Additional and further testing does need to be done and I will be contacting them to team with me on some testing I have in the works...now if stock that was 2 weeks out 3.5 months ago would ever arrive lol.

Sincerely,
Theis

 

[TripleBull]

http://www.btgresearch.org

Neat stuff, like this one in case you need to calculate the drop on your potato cannon next time you want to blow out your neighbor's front window:

https://arxiv.org/ftp/physics/papers/0612/0612118.pdf

I need a potato with a better potatolistic coefficient!

 

[THEIS]

LOLOLOLOL,

I hadn't seen that one....

I am waiting to hear back from the in regards to the acoustic methods developed and utilized in their external ballistics testing.

 

[lash]

Hi,

Here is entity that conducted test. Might want to check their resume and current projects ?

http://www.btgresearch.org

Edited to add: Additional and further testing does need to be done and I will be contacting them to team with me on some testing I have in the works...now if stock that was 2 weeks out 3.5 months ago would ever arrive lol.

Sincerely,
Theis

Thanks for the info. I did look into the testers and the authors a bit and restate that I do not really question their accuracy nor test results. I merely just wanted to point out the obvious questions anyone serious would ask after reading the white paper.

I appreciate the information that you, THEIS, have been providing for the consumption of some of us that find this very educational. In addition, I look forward to the testing that you will be doing and the resultant additional data you will provide for the community. ??

 

[THEIS]

Hi,

So Roy has updated his website quiet a bit. He has some high speed pics and various videos showing and highlighting his suppressor designs.
I recommend digging through his site, if for nothing more than reading for sake of researching data

https://www.acadianarmament.com/predator-tss-two-stage-silencer

I talked with him at length today in regards specifically to his design on the big boomers such as the BMG, BMG Wildcats, Cheytacs and CT wildcat cartridges.
I am going to meet with him in a few weeks to put pen to pad on some things.

Sincerely,
Theis

 

[missed]

Coming back later to read

 

[timintx]

Very interesting thread Theis, Thank you for the info. I have been working on suppressor research that addresses some of the same problems with suppressors and have talked with the guys at navel surface warfare on these issues as well. About 5 years ago I was tasked by them to build a 300 win mag suppressed using some new tuning technology which has do do more with weight on the muzzle,I said no problem. Shortly after another gentleman came up to me and gave me a list of things they wanted corrected to do with suppression,so I set out to work on a suppressor that will first tune for weight ,second will direct turbulent gasses away from the bullets flight path ,third will force the laminar air through a venturi which will straighten out a bullet in flight just as it leaves the muzzle, the pitch and yaw that is produced in a jacketed bullet is not from gasses hitting the bullet as much as the center of gravity offset and center of pressure change as the bullet has been reshaped from the trip down the barrel and the pressure behind it bulging the ogive of the bullet. Seating depth initially is the culprit as to the change at the muzzle. There may be suppressors that do not exacerbate the pitch and yawing but there are none that can straighten a wobbly bullet in flight that i am aware of except the venturi design I am working with.sound reduction suffers a few decibels but ultimately the rifle can shoot any seating depth now to extreme ranges with little no change in grouping. The patents are done and ready to go and hopefully the military will take a good look now. The sad part is the rifle I built for the navel surface warfare was tested ,calibrated and ready on time to the day,when I contacted them I was informed the project had been cancelled. It made me sick.

 

[Mooncake]

Nice -- this is exactly the kind of stuff I came here looking for. Thanks, OP.

 

[THEIS]

Hi Tim,

I am looking forward to seeing how your technology scales up to the big bore systems. The success you have had with your WM cannot be discounted.

Sincerely,
Theis

 

[timintx]

Stay tuned we will know in a few weeks at the king of two miles,the 375 should be done in two weeks which only gives me a week or so to get it tuned and ready ,it is going to be close.

 

[IntoTransonic]

Stay tuned we will know in a few weeks at the king of two miles,the 375 should be done in two weeks which only gives me a week or so to get it tuned and ready ,it is going to be close.

Tim
It better be ready. If you need help motivating our buddy .... let me know and I will, with enjoyment, give him a swift kick in the ass with my size 12’s. Look forward to seeing you soon.
Chris

 

[timintx]

Chris , He did good it is on the way to me and everything should arrive Friday,

 

[timintx]

Hi all , I thought I would post some of the final vibration structuring that we did on the 375 right before the Ko2m. This is a graph of actual barrel movements on paper similar to a ladder test but we fire one shot in each column with 1 grain difference in powder at 100yds to see where the barrel is pointing at different exit times. This mode of vibration is vertically oriented due to weight differences below and above the bore center line ,it is not suppressed yet but we decided to use a brake for the weighting to see if we could achieve our tuning goal before building the suppressor because of time constraints mainly. I did not shoot well in the Ko2m but never the less the rifle shot great with misses that were small and in practice showed very good promise with first shots hits at 2400 ,2000,1760 and with no vertical dispersion showing at any time. Any barrel muzzle will move downward at a drastic rate under recoil as the rifle bows up in the middle under recoil giving large vertical dispersion with very little change in velocity and with the wrong weight be it suppressor or brake this effect can be exacerbated due to that fact alone. Right before the large downswing there will be a upswing which is very small but is the ideal tune area with minimum vertical at the target. Since the upswing is very small what I am doing is to widen the upswing and to smooth out the little ripples contained within the upswing. This condition will give an infinite tune regardless of what velocities are due to temp change. The rate of upswing is changed as well until we see no vertical difference at the target while shooting 1 grain difference in powder charges to create differing velocities . A standard tune will see a gradual drop of poi as the powder charges decrease. We have structured the vibration for one big long smooth upswing which ultimately gives the best tune for extreme range.

 

[TomH Tx]

This entire topic is very interesting. I am a relative newbie at all this, and my place is really only safe lof to 750 yards. However, I have seen that when I am shooting either my .308ar or my ruger rpr 6.5, suppressed, it takes an additional .5 or .6 mils up over whatever is stated for StrelokPro, Ballistics, BallisticsARc, or even Trasol, for a 12" paper splatter target at 625 or 725 yards. The deviation from the shooting apps seems to increase above 500 yds. I have noted that the suppressor does not seem to affect l/r windage. This forum is an amazing resource, and I look forward to continuing to learn all that I can. Thanks to all. Now I am going to back to the beginning of this thread, and read it again.

 

[timintx]

Tom ,One note I should have added is the additional weight will sag the barrel down away from your line of sight which is common for suppressors to drop point of impact . The generally accepted rule of thumb is for every .001 of barrel sag equals 1 moa at 100yds.so if your rifle is sighted in without a suppressor then screwed on and sagged the barrel .006 then you would see about 6 moa low at the target, however the vibration structure created by that particular weight can change the formula as well to the point of seeing 0 poi change due to the changing muzzle angles at the time of bullet exit.there are other factors involved to do with baffling of the suppressor but the weighting portion of a suppressor is the main thing I am speaking of.

 

[TomH Tx]

Tim: I would never have thought of "barrel sag". When I re-verified zero at 100yds on the rpr for example, after attaching the suppressor, it only needed .1mil adjustment to zero. It is further out, at 500+ yards, where I see an increasing divergence from the ballistic apps. Therefore, I assumed that it had to do with loss of muzzle velocity. I will convert your numbers from moa's to mils and try to see if that correlates to what I am seeing in the field. Thanks!