Originally Posted by Rhettsker
Originally Posted by Kimber7man
6.5 Creed with 20” Bartlein #3 barrel threaded 5/8x24 for the TBAC CB.

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I thought with a Bartlein 3 contour, you only have enough meat for 5/8x24 threads out to 18”? With the 3b contour, you can get 5/8x24 at any length. Am I misinformed?


You’re not misinformed, but there may be some room to fudge (depending on who you ask, I’m not a gunsmith and I’d always say defer to a professional)

The typical recommendation is that you need .725” muzzle diameter for 5/8” threads with a proper shoulder of .050”
.725” - .625 (5/8” major thread diameter) = .100” left /2 equals a .050” shoulder all the way around.

In the past I’ve had a Shilen 4 and Brux 4 threaded 5/8” at approx 20”. These contours are close to a Bart 3. IIRC the muzzle diameters were .715-.720”. Worked fine with my suppressor, just didn’t quite have the minimum shoulder left that the folks at Thunderbeast would like to see. Technically speaking, you could have anything over .630” or so threaded 5/8”, you just wouldn’t have a shoulder left for the suppressor to lock up against.