After perusing the latest discussions around here on the subject of muzzle brakes, I thought I had better to head to the range and do some scientific testing. I personally have two rifles with Vias brakes and while the manufacturer claims virtually no increase in noise, I wanted to see for myself. Noting some of the discussion in the previous thread, I decided to test (with a decible meter) the various rifles both from the shooters position and also from a position 7' behind and 3' to the right of my shoulder. The idea with the second placement was to appoximate the noise level for a guide observing his client's shooting.

I started with the baseline of a Kimber 84 .308 22" barrel shooting 150gr. handloads. The shooter's number was 115 while the guide got nicked at 113. Next up I tested a custom M70 30/06 with a 25.5" tube and a Vias brake firing factory winchester 180gr silvertips. The shooter's number was 115.4 and guide's number was 113. Getting to the meat of the matter, the next test was run with another custom 70. This time a 26" .300 win mag was tested with and without it's Vias brake shooting 190gr. handloads. The with brake numbers showed 116.5 at the shooter and 115.4 for the guide. Without the brake, the shooter got rung to the tune of 115 and the guide got 113.4. The final test was run with an 8" Freedom Arms .454 Casull firing Winchester's 250 grain factory load. The shooter got lit up for 116.2 and the guide got 112.4.

The evidence shows that although some brakes are indeed very loud, the Vias does meet the makers claim of negligable noise increase. The factors most involved in noise seem to be gas velocity and more importantly, barrel length.

Correct me if wrong.
The decibel scale is logaritmic,witch means that every time you increes the noiselevel by 3 db you dubbel the noice.

If i ame corect, the brake incresed the noice by 50-70% depending of the position

Not completely correct jorgen... It requires about a 3db increase for the human ear to be able to notice the increased volume....

Excellent test papaschmud... At least there are some hard numbers involved here... Simply depends on which direction the gas is vented as to where the noise goes....

Ken....

quote:

Originally posted by jørgen:
Correct me if wrong.
The decibel scale is logaritmic,witch means that every time you increes the noiselevel by 3 db you dubbel the noice.

If i ame corect, the brake incresed the noice by 50-70% depending of the position

You are correct when you mention that the scale is logarithmic. My understanding is that an increase of one decibel is an increase of 100% of the intensity of the sound. Intensity and perceived volumn are clearly not the same.

The numbers are only useful in that they are comparative and non-subjective. No one would call a 22" barreled .308 a boomer but some folks might shudder in aprehension at the prospect of hunting with an '06 wearing a brake.

I realize all brakes aren't equal, but the Vias has proven in non-subjective data that their brake performs as advertised.

One more note about decibel measurement: I tried testing the meter by subjecting it to loud noise and then slightly varying the volumn of that noise. At over 100 decibles, the difference between say 107 and 110 was very slight. It was perceivable, but only that, not a marked difference. To learn more about decibel measurement and sound perception click the link below.
sound tutorial

Why weren't the first two rifles tested both with and without brake?

The .308 doesn't have one.

When I measured the '06 with the brake on and discovered it was no louder than the .308, I thought it pointless to test without the break as it was already rather mild.

This is great, I've been hoping someone would do it with a meter. I wish you had more rifles to test.

I'm still trying to understand how much louder a few decibels is. I need to read your physics lesson again.

What was your perception of the recoil reduction? I called Vias once and they said the recoil reduction was greater at high velocities.

I could test all sorts of rifles. Based on the numbers so far, I don't think that most of the "normal" stuff would vary that much.

I bedded and did load developement on an A-bolt (with the BOSS) in 7 rem mag that I'd like to get back here and check both ways. Another neat one to test would be the Competitor .243 specialty pistol I worked on some years back. This pistol had a conventional brake which vented at a 90 degree angle from the bore. Brutal. The noise was overpowering. I took the brake off for the load work.

As far as recoil, the '06 is a cupcake. The brake doesn't hurt, but this rifle wouldn't be hard to shoot either way as the barreled action is a m70 and the barrel is long. It also wears a Pacific Research (now Borden) stock whose dimensions help. As it is, you can't quite watch the bullets hit through the scope, but if I need to shoot from a weird position, I know the scope won't hit me.

The .300 has a noticable increase in recoil without the brake. It's not that hard to shoot bare but with the brake you can shoot it all afternoon.