Range Report Muzzle Brake vs MV

[_Windrider_]

Rifle is a factory barreled RPR
Ammo is factory Hornady 140gr ELD-M

MV at 70 F with factory brake was 2687 verified with MS V3

MV at 43 F with SilencerCo ASR Brake was 2688 with same MS V3.

i was expecting, based on all my other data, that the MV at 43 F should be around 2621.

Can a muzzle brake change the MV that much? All my previous data was collected using the factory Ruger Brake and this was the first range day with the SiCo.

FWIW, ES and SD were constant ES 45 and SD 16 at 70 F, and ES 46 and SD of 16 at 43 F.

 

[Mordamer]

Was your ammo at ambient temperature? If you had your ammo in a 70 degree F house or car and then took it outside and shot it within minutes of exposing it to the cold there is a pretty good chance that the powder temp was still up around 70 degrees.

Have you tested with a bare muzzle?

Had you tested at different temperatures with the same muzzle brake?

This is a classic example of changing 2 variables at one time. You will not find a definitive answer from someone on this forum. If you are looking for anecdotal answers I'm sure you will get plenty of that.

 

[_Windrider_]

i always leave the ammo at ambient. the mags were pre loaded at home and first thing i did when i showed up to range was take them all out and set them on the table while i set up. they sat out for a good 45 while i dicked around and chatted with a fellow range member. also verified with a laser thermometer before shooting.

have not fired without the brake. the SiCo required a crush washer and i didnt want to take it off at the range. I expected some difference, just not over 150 fps increase at that temp (again based on all other data at warmer temps with same ammo). i get about 1 fps/2.6 degrees verified with factory brake.

im just curious if people have seen this kind of increase with a brake change. clearly i have to reverify other data but i may save mydelf the headache of a 3rd try as i will likely be switching brakes again to an Area 419 self timing hellfire.

 

[Mordamer]

If you get 1 FPS/2.6 degrees change then that would only be a little over 10 FPS from 70 degrees to 43 degrees.

 

[_Windrider_]

2.6/1 degree. had a moment of dislexia. 5 out of 3 of us have it. so with a 27 degree difference (70-43) i should see about 70 fps drop....about 2617 (2687-70).

again, never do this on an iphone. i keep telling myself that and i keep forgetting.

 

[Yondering]

im just curious if people have seen this kind of increase with a brake change. clearly i have to reverify other data but i may save mydelf the headache of a 3rd try as i will likely be switching brakes again to an Area 419 self timing hellfire.

No. I like brakes, so I've built and installed my fair share, and have never seen one contribute significantly to the velocity. I think you're seeing the effect of other variables, or in other terms, maybe the lack of temp sensitivity for that load. Temp sensitivity is not necessarily linear as well, but either way you're talking about a pretty minor difference in velocity.

 

[Rthur]

Haven't tested this across the chrono.
Could be a worthy test of sorts.

R

 

[B y r o n]

Is it possible that the powder that Hornady is using is more temperature friendly so the velocity stayed the same?

 

[_Windrider_]

Is it possible that the powder that Hornady is using is more temperature friendly so the velocity stayed the same?

Well between 70 and 88 i get 2687 and 2737 respective, so i would expect a lower velocity at colder temps. but who knows. ill just note it and carry on.