[BradB]

Does anyone know what thread is used on the end of the barrel for a win model 70 with a boss in .338 win. I'm thinking it may be some bastard thread to keep people from screwing other things on there. It appears to be 24 tpi and the major dia. measures .583. I'm wanting to make a sleeve to cover /protect the threads when the boss is not there, the sleeve will be the same o.d. as the barrel to give the barrel a better look. I'm not wanting to cut the barrel and recrown, just don't want the boss on there. At this point I guess I'll just cut a thread with .585 maj. dia. with 24 tpi and see if it screws on. Thanks

 

[kdub]

Doesn't Winchester and Browning sell these thread caps? Seems to me they came with the "Boss" and a cap for when you didn't want the compensator on the muzzle.

 

[unclenick]

They make a ventless Boss. Lots of folks don't mind the recoil and don't want the noise and muzzle blast of the brake, so they came up with one that still functions as a barrel tuner but is solid along the sides.

Caps, I don't know about. You could buy a spare BOSS lock nut and just shoot with two lock nuts on. That will protect the thread.

My thread gauge and my micrometer show 24 TPI and 0.561" major OD on my mid-90's Browning A-bolt. That would appear to fit just inside 9/16-24, but 0.0015" is too tight for commercial threads. 5/8-24, the next commercial size up, is too loose. I'm going to guess the one on my Browning is meant to be a 0.575-24 thread. I base that on a commercial thread crest that is 70-80% of sin60°*/24" at the crest. If that's right, then about 0.014"-0.021" needs to be added to the diameters of the barrels to find rated thread OD. That works out to 0.575" pretty closely for me and makes yours look like it was intended to be 0.6-24. I bought mine circa 1995, and they may have changed it since then?

Anyway, if you are sure of your 0.581" reading, I would start with a 0.535" hole on a lathe and and run the internal threading bar in until you can screw it onto the barrel. If you mistyped and have 0.561" thread OD on your muzzle, as I do, then you want a hole 0.515" to start internal threading.

 

[BradB]

Thanks unclenick! Yes, it measures .583 and I will do what you said. As long as it screws on and snugs up it will work fine. Going for the look of a non boss barrel, you'll still see the numbers on the barrel but I'm not ready to just cut it off. The recoil is very manageable without it. Thanks again. P.S. Sorry for posting in the wrong area.

 

[kdub]

Don't worry about the proper forum posting, Brad. That's what keeps the Moderators employed on the board! (As Unclenick would say - "the benefits are great!).