View Full Version : 243 nato

06-25-2015, 05:46 PM
I have a semi auto 243 and an M1A. I have 7.62X51 NATO brass. I was thinking that resizing some of that to 243 might give me a good and durable case for 243. Any thoughts about that?

06-25-2015, 05:56 PM
make sure the neck is not too thick after the sizing process, need to have bullet release room

06-25-2015, 06:02 PM
The 243 will be shorter than spec, been there done that. And it requires reaming to make work..

country gent
06-25-2015, 08:13 PM
Brassthickens when sized down ( all the extra has to go somewhere). Getting the shoulder set to correct headspace is important but more trial and error than hard to do. Thinning necks is a little diffrent neck turning or neck reaming a large batch of reformed cases can be a chore to do. It would be alot of work on multiple fired cases. New or once fired may be okay but multiple firings or machine gun fired brass may not have the life left in it. You definitly want a good case lube and heavy press.

06-25-2015, 09:01 PM
Make sure the brass is not too thick after forming. With most generous factory chambers it will not be too thick.
But you need to anneal it after forming or the necks will crack.

Airman Basic
06-25-2015, 09:02 PM
I've done it. Straight to .243 forms a slight groove that irons out on first firing. Turning or reaming is necessary but only once. Annealing too or they won't last long. Used RA 1980 stamped military brass and still using some of them. Worth it, I think, especially if you're into this nit-picky stuff like I am.

06-26-2015, 08:58 PM
I used to do it but neck turning & annealing should be done.