Muzzle brake design/installation

thud · July 30, 2003, 18:02

Per Roy's Precision Shooting page on Adventures with Muzzle Brakes the concentricity of the exit hole on a muzzle brake needs to be no greater than +/- 0.0005" for accuracy not to be effected. Concentric to what? Concentric to the flight path of the round and to the bore of the rifle or concentric to the brake? Or is he talking about angular alignment to the flight path?

If he is talking about concentricity to the bore, how do you achieve that
level of tolerance for a threaded device. The only way I can see of doing it right is to install the brake and lap the exit hole. I can get the exit hole angularity almost perfect, but after flipping the brake around in the lathe, I keep ending up with about 0.003" out of alignment. If I try cutting everything from one end, I still end up with alignment problems. Besides, I don't think the FAL bore is concentric to +/-0.0005" to the barrel outer diameter.

Any suggestions or do I need to hold that tight of a tolerance.

Rifle_Guy · July 30, 2003, 18:32

Seems to me that reamers are avilable that pilot on the bore and ream the exit hole. This might solve the problem. Try Brownell"s.

July 30, 2003, 18:02	#1
thud Registered FALaholic #: 4725 Join Date: Nov 2001 Location: Stafford, Texas Posts: 87	Muzzle brake design/installation Per Roy's Precision Shooting page on Adventures with Muzzle Brakes the concentricity of the exit hole on a muzzle brake needs to be no greater than +/- 0.0005" for accuracy not to be effected. Concentric to what? Concentric to the flight path of the round and to the bore of the rifle or concentric to the brake? Or is he talking about angular alignment to the flight path? If he is talking about concentricity to the bore, how do you achieve that level of tolerance for a threaded device. The only way I can see of doing it right is to install the brake and lap the exit hole. I can get the exit hole angularity almost perfect, but after flipping the brake around in the lathe, I keep ending up with about 0.003" out of alignment. If I try cutting everything from one end, I still end up with alignment problems. Besides, I don't think the FAL bore is concentric to +/-0.0005" to the barrel outer diameter. Any suggestions or do I need to hold that tight of a tolerance.

July 30, 2003, 18:32	#2
Rifle_Guy Registered FALaholic #: 2295 Join Date: Jan 2001 Location: Chandler, AZ Posts: 498	Seems to me that reamers are avilable that pilot on the bore and ream the exit hole. This might solve the problem. Try Brownell"s. __________________ http://i245.photobucket.com/albums/g...member1102.png http://militarysignatures.com/signatures/member1102.png If arms are instruments of power then, in a republic, do they not, rightly, belong in the hands of the people?

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