No Turn Chamber

[jsteag]

What do they mean when they say that the barrel has a no turn chamber?

[EFBell]

you can order a wildcat chamber as "no turn" where you dont need to neck turn the parent case after resize. There are other cases as well.

[Nefarioud]

It means that the cases don't have to be neck turned to fit.

If you go to http://www.shilen.com/chambers.html and look at .308 Win. you'll notice that there are three listed. One is standard Saami spec (which I forget the dimension at the moment) One is .340 which is tighter but should be "no turn" (most of my loaded rounds measure .335 at the neck) and then there is a .332 which would require the neck to be turned to fit.

I use the standard chamber in all of my .308's, My buddy has his all done in .340 we seem to shoot about the same. The main difference being the amount the brass is worked during resizing (mine being more) but we both anneal so it's not that big of a difference.


P.S. I was typing this when EFBell answered so I posted it anyway :)

[EFBell]

No problem there Nef-D, those are just some of those "other cases" as mentioned.

[Con]

Exactly as stated above!

I'm considering ordering a 223AI reamer that is 'no turn'.

Most of the factory 223Rem brass I've measured (with projectile seated) go about 0.247". SAAMI spec on the neck is 0.255". I want my reamer to cut a neck at 0.250".
Cheers...
Con