View Full Version : 308 to 300 WSM

May 15, 2002, 07:34 PM
Does anyone know if its possible to rechamber .308 to .300 WSM? I know the rate of twist may not be ideal but it does vary from maker to maker.

Art Eatman
May 15, 2002, 08:33 PM
Dunno how much the rate of twist is different, unless the WSM is faster, favoring heavier bullets.

Biggest problem, probably, is the diameter of the case head. Quite a few articles in the gun rags, talking about both the twist and the dimensions...


Don Martin
May 15, 2002, 10:03 PM
Of course it's possible but it's not practical. You will end up with a rifle that has a marked over barrel, money spent on the bolt face and feed rails and bolt stop.

The twist of the most .308's is 1-12 and that's enough for at least a 180 gr bullet but the big thing is the money.

A typical used .308 bolt rifle may be worth $300 and a new .300 WSM costs about $610. You will have a hard time being able to sell a worked over .308 that's now a .300 WSM however.

Just sell the .308 and buy a .300 WSM. Better keep the .308 and buy a new .300 WSM!

May 15, 2002, 11:02 PM
Thanks for the info. I was not aware that the base of the case was a different size. Not worth doing.

May 20, 2002, 09:12 AM
In Germany/Austria the legal max. pressure of .308 is 4150 bar, of 300 WMR is 4300 bar.
Thats a little difference.
If you ream the chamber you will weaken the barrel end...
I think it would be quite dangerous to do.