Check barrel thread concentricity?

[RacerX]

Here’s my question... I have some rifles that will eventually become hosts... if these are factory threaded barrels, should I have a gunsmith check the threads for concentricity? Thinking ahead to avoid baffle strikes, etc...

Barrels are by Stag, Ballistic Armament and PSA.

 

[Zbizzle911]

Get a wooden dowel that fits close to snug in barrel. Put the suppressor on and put dowel in bore. If it fits shoot it. If it doesn’t line up don’t.


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[JimP42]

Similar idea but way more precise. You can get steel rods in nearly any diameter you need. I have several 3’ rods in these diameters:
.339 (9mm)
.2969 (.30)
.2120 (22LR)
.2188 (223)
.4375 (45)

Probably got them from Grainger or similar. About $8 each IIRC. Those will be much better fits, easier to determine contact with baffles, straight, and inflexible.

Oil them before use, and of course don’t force anything, and it won’t hurt barrel.

 

[BigWaylon]

I put the silencer on, then remove the BCG and look down the barrel. Sometimes shine a light and look to see if the shadow it creates is a circle.

Never used an alignment rod.

Only one I’ve had issue with was a PSA 300BLK barrel.


It’s not just concentric threads to worry about. You also need a square shoulder...unless you have a setup that aligns on the muzzle.

 

[shadowsbane]

McMaster car has rods for cheap. Mich cheaper than those ones marketed for suppressors.

 

[some_kid6]

McMaster car has rods for cheap. Mich cheaper than those ones marketed for suppressors.

If you get these just make sure you get the ones with a straightness tolerance otherwise you might end up with bowed rods. 8890K prefix. CNC Warrior also makes some on a lathe to guarantee straightness/fit.