Hello

Anybody know what it is? Calibres other than 338 Win Mag which are apparently all the same.

Thanks.

I.need to know the same thing I.have a couple of 338 boss systems .I want to put one on my stainless 338 Ruger 77 win mag and one on my ar10 260 Remington that's already threaded .

I could be wrong about this, so I won't be wrong and I'll give you two options. You pick the one that's closest! (I'm not saying that either one will work) LOL

Common sense wants to say 9/16x24 because that is the thread a sane person would use. But my little voice is standing up and screaming: "DON'T SAY 9/16X24"
Say M15x1.0 ! ! ! ! ! ! ! ! !
I hear my little voice screaming at me all the time. The problem is that while I hear him quite well, I don't always listen all that good and I should. He's much smarter than I am !

I just spoke to my local Winchester guru on another matter. He says they are 9/16 x 24 TPI. He also says the exit hole in the 338 is proprietary. All of the BOSS systems from 22 through 308 are the same size hole. 338 is larger so you don't want to mix them up.

I.know they work.for accuracy very well .My 338 win.mag model 70 Winchester shoots 7/8inch at 200 yards with factory ammo .I want to try to make an adaptor to put the boss system on a few rifles .My Ruger mini 14 ,target rifle shoots 1/2 inch at 100 yards so you know it works they are just ugly !