Concentricity

[eleven]

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[tehpwnag3]

I believe this is most important when attaching a suppressor to an appropriate muzzle device to avoid baffle strikes. If the barrel is not threaded concentric to the bore, this can happen.

[SomeOtherGuy]

Concentricity matters more as the muzzle device gets longer or has a smaller opening for the bullet. It's a non issue with the A2 and some other common flash hiders based on their design. Even with most brakes, it's not an issue unless it's far off. There are a few brakes (the Precision Armament AFAB comes to mind) that use an especially small opening to maximize their effectiveness, and therefore require better tolerances. But in general sound suppressors are the most demanding, because their baffles have a small opening AND may be 6 or 8 inches away from the muzzle, so a tiny error at the muzzle threads can become a problem resulting in baffle strikes, while the same error would be a nonissue with an A2 flash hider.

[redmist]

Concentrically of the bore is always discussed, however many muzzle devices get a pass. Depending on manufacturing process, the device itself could be the culprit. Obviously a suppressor amplifies the problem.

[1371marine]

Exactly what he's saying here. The first barrel/FH combo as they came may have been concentric. Now switch said FH to brand "B" with a manufacturing boo boo and well... now it's non concentric. Not a real issue until you mount a $800 or $1000 can. If this is the case and you're a DIY, invest in some drill stock and check it youself before putting rounds downrange. The first round could very well be the last for that new can and that would really sting.



Concentrically of the bore is always discussed, however many muzzle devices get a pass. Depending on manufacturing process, the device itself could be the culprit. Obviously a suppressor amplifies the problem.

[GH41]

Isn't this the reason most devices meant to receive a can specify NO crush washer? It would be pretty hard to machine the shoulder of the barrel or back of the muzzle device out of square. Back in my IPSC open days we used a bore guided reamer to assure the bullet would clear a tight comp. GH

[_Stormin_]

Isn't this the reason most devices meant to receive a can specify NO crush washer? It would be pretty hard to machine the shoulder of the barrel or back of the muzzle device out of square. Back in my IPSC open days we used a bore guided reamer to assure the bullet would clear a tight comp. GH

It's not the shoulder where the treads are cut that's off of square, it's the fact that the bore is not "perfectly" true down the center of the barrel blank. It wanders off the slightest bit. I wouldn't think that this is a huge issue with a quality barrel from a trusted MFG, but some of the experts here have probably seen it from many of the big names. IIRC, KLDavis' thread on the science of barrels goes into the whole thing in great detail.