muzzle brakes and why

[68wicked]

Ok I'm new to the AR world. Can someone enlighten me on why I see so many AR 15 set ups with brakes. Am I missing something I'm old school bolt and I only had one rifle that I had a brake on 300 ultra mag. 223 is like 3.5lb recoil my 300 blackout is around 5lb and I think that my Grendel I'm building with adjustable gas block and weight should come in in or under the blackout in recoil. Thank you.

[Klem]

A lot of brakes are actually flash eliminators and are on civilian firearms for cosmetic reasons. Unless you are seriously into prepping where you convince yourself a flash eliminator will confound the bad guys as you sneak around doing your thing when society collapses. Others have flash eliminators because it is de-rigueur on a military style rifle.

Those that do have proper muzzle brakes are wanting to lessen recoil, not because they have to but because it helps with muzzle rise in light guns and keeps the sight system closer to the aiming point for quicker follow-up shots. You can also often see the splash on distant targets rather than having to rely on a spotter.

Finally, if you are prepared to put up with a louder firing point, spending a bit more money and a slightly longer barrel you get less recoil. Less recoil is always better than more so it's up to you and whether you think is worth it.

Your adjustable gas is not going to change the felt recoil of that Grendel. A muzzle brake and the weight of the gun will however.

How have you determined those recoil figures (3.5 and 5lbs)?

[terrywick4]

Your adjustable gas is not going to change the felt recoil of that Grendel.
(3.5 and 5lbs)?

I disagree! the adjustable gas does have a big effect on felt recoil. If after a shot the bolt only goes back far enough to cycle the gun instead of slamming all the way back then the buffer spring takes energy out of the recoil. I definitely felt the difference when I went from straight gas to adjusted.

[68wicked]

I found the recoil date by Chuck hawks unde rifle recoil chart. Think you for the input.

[Klem]

I disagree! the adjustable gas does have a big effect on felt recoil. If after a shot the bolt only goes back far enough to cycle the gun instead of slamming all the way back then the buffer spring takes energy out of the recoil. I definitely felt the difference when I went from straight gas to adjusted.

Yes, I see what you are saying so please ignore my last post.

I've been trying to reconcile what you are saying with Newton's Second (Force=MA) and Third Law of physics (action = reaction). If you send a bolt carrier group with speed back to the firer then the firer needs to 'push back' in order that the recoil spring can absorb and temporarily store that energy. If it comes back with less speed due to gas regulation then less 'push-back' (felt recoil) is needed - You are right.

This is in isolation of any muzzle brake you might have on at the time. If you did have a muzzle brake then by regulating the gas at the port this means more gas goes out the muzzle so the force on the brake pushing the gun forward is higher than in a non-gas regulated system. I'm thinking that gas regulation with a brake helps tame (felt) recoil in two ways; less bolt momentum to oppose, and more pressure on the brake pushing the gun forward.

Does that make sense?

[worthen86ford]

Klem, that's one hell of a train of thought. It's fully understandable though. At least for me...

[rabiddawg]

I disagree! the adjustable gas does have a big effect on felt recoil. If after a shot the bolt only goes back far enough to cycle the gun instead of slamming all the way back then the buffer spring takes energy out of the recoil. I definitely felt the difference when I went from straight gas to adjusted.

I can't say I felt a difference when I changed two of mine but it makes sense to me IF the unregulated charge sends the carrier as far back as physically possible.

[Rickc]

Shoot a. JP rifle tricked out and you will see just how well recoil can be controlled in the AR platform

[LRRPF52]

Primary recoil impulse comes from the detonation of the cartridge in the pressure containment vessel, in this case, the barrel/bolt combo housed in the frame. Not much you can do about that other than recoil pads and maybe a recoil absorption system built into the hard gun, separate from the gas system.

Secondary recoil impulse in the AR15 comes from the buffer bump pad, buffer body, and bolt carrier against it impacting the rear inner end of the extension tube.

There are actually some additional impacts after this, comprised of the floating buffer weights, which all feels like one impact due to the short moment in time that it happens.

The impact of the bumper pad redirects the inertia 180 degrees, sending the buffer, its internal weights, and BCG forward at the cyclic rate, which is then somewhat retarded by the stripping of a fresh cartridge from the magazine.

The final felt recoil impulse is the carrier slamming into battery against the barrel extension.

A combination of efficient muzzle brake, tamed gas system, and balanced recoil system can make an AR15 feel like a .22 short, but with massive concussion at the muzzle. The biggest disadvantage of such systems is when the gas is choked so much that the rifle will short stroke in colder weather, so that is one thing to keep in mind.

Another is that when choking your gas, you exacerbate gas port erosion. One way to counter that is to use different surface treatments or cryogenic treatment, like JP does, resulting in unbelievable barrel life.

I was just testing 3 different 20" Grendels today at a local range. 2 had flash hiders, the other has a large gilled muzzle brake.

The braked gun is much easier to watch your hits with and follow-through with, exhibiting minimal muzzle rise.

[Bisley]

Two of the biggest reasons are squirrels and arthritis. For ground squirrels it allows you to call your own shots, which is a real help, especially when shooting alone. It also allows you to see the aerobatics lol. The arthritis is self explanatory. I have broken both wrists three times apiece and if not for the brake I could not shoot many times. It can flare up for long periods with no signs, and even the .223 kills me. Not with the brake. Even the .308 is tolerable with the brake. You can actually watch your hits with the .308 and the brake.

On a side note, as far as brakes go, I highly recommend the Precision Firearms LMD. I have it on the .223 and 6.5, and it works almost as great as the Precision Armament M 41 but without hardly any noticable gas back at you.

[68wicked]

Thank you for all the input. Might need to call my barrel guy and thread it.

[85_Ranger4x4]

My brother has a YHM brake on his 5.56 (for the moment) The thing is ridiculously loud, you can even feel it in the ground when it goes off shooting offhand.

Not sure if it really helps recoil, it made me flinch as the noise went thru my earplugs.

I just use the boring A2 flashider. The recoil to me is pretty negligible with my 5.56 and 7.62x39. I have another A2 for my 6.5G build.

[SightedIn]

I have a JP brake on my 18" grendel and I love it at the range. Back on target quick, and recoil feels like maybe %20 more than a .223.
Without it recoil feels like %20 less than a .308.
I take it off for hunting trips though (and put a thread protector on), its simply too heavy for that, and well when hunting i seldom take more than one shot...

[sneaky one]

SI, same reason for me too, perfectly stated.