Muzzle brake back pressure?

[1lostinspace]

I installed a FSC556 flash/muzzle brake on my AR 15 and started having pierced primers, I changed the firing pin,hammer spring, different bolt and finally I called them and they said it was the first time they had heard of that happening, my girlfriends dad installed one on his rifle and he is getting blown primers from time to time using American Eagle. anyone had this problem with a brake before?I now have my Phantom back on and have not had a single problem so far 300+ rounds.

[Fuzzy5]

I haven't heard of that happening before but I was looking at the FSC556 and the DNTC specifically because PWS claims an increase in backpressure which can assist in cycling. I figured with my 18" barrel and rifle-length gas system, a little extra backpressure would be beneficial.

Let me know if you want me to take that primer-puffing piece of trash off your hands!

[Forestgnome]

Pressure effects like you describe happen way before the gas reaches the brake. Very unlikely the brake could cause this. It's the ammo. If you havn't seen the problem for a while, try putting the brake back on.

[1lostinspace]

Pressure effects like you describe happen way before the gas reaches the brake. Very unlikely the brake could cause this. It's the ammo. If you havn't seen the problem for a while, try putting the brake back on.

I am not putting the brake back on unless I see the problems arise again canceling it out. The ammo is the same load I have fired over 3k times. I reload and know all to well the signs of pressure. The Brake works great and if not for the back pressure I would be more then satisfied with it.

[Forestgnome]

I am not putting the brake back on unless I see the problems arise again canceling it out. The ammo is the same load I have fired over 3k times. I reload and know all to well the signs of pressure. The Brake works great and if not for the back pressure I would be more then satisfied with it.

Whatever you do, don't reinstall it! send it immediately to me for a little destructive testing.

[Stockton]

never heard of that happening. pierced primers from a break...very interesting on a ar platform.

do you have another break to test? if not leave it off and sell that FSC

curious...what is your barrel length? ammo recipe? saami?

[aplinker]

never heard of that happening. pierced primers from a break...very interesting on a ar platform.

do you have another break to test? if not leave it off and sell that FSC

curious...what is your barrel length? ammo recipe? saami?

Muzzle devices can absolutely change the pressure in the system. I'm surprised it's enough to cause overpressuring.

Device choice affects how you'd drill the gas port in the barrel.

[ar15barrels]

Muzzle devices can absolutely change the pressure in the system. I'm surprised it's enough to cause overpressuring.

Device choice affects how you'd drill the gas port in the barrel.

Muzzle devices can only change the pressure effects of what happens after the bullet leaves the barrel.
All the pressure signs you see are happening before the bullet is 5" down the barrel.
You might see function changes from a muzzle, but you won't see pressure changes.
Perhaps you are just bad at reading signs...

[Forestgnome]

Max SAAMI pressure for the .223 is 55,000psi. By the time the bullet is passing the muzzle brake, psi is under 20,000. Primer flattening would probably be occuring above 60,000psi.

[ar15barrels]

Max SAAMI pressure for the .223 is 55,000psi. By the time the bullet is passing the muzzle brake, psi is under 20,000.

Or even less...

[1lostinspace]

I not sure what is happening all I know is that the rifle is functioning normal again.