OK, so like an arse I gave all my 300 wsm stuff back to my buddy. Shellholders, dies, brass, bullets, everything and now I'm kicking myself for it (his rifle anyways).
So I turn my house upside down and find a single piece of 300 wsm brass as a consolation prize which represents all the material I have till I get on the phone and call my buddy to ship it back
Anyways, I already cut it to .355 and test fit. DEFINITELY not even close to no blowback without an O-ring (no solution seems to have no blowback without an O-ring!) but given the case thickness down there, it's a pretty slick solution. LRM primers arent even close to the power of the 209's I have but maybe that's best anyways. I will definitely try these at the range!
But I have a question. Is there any way to have the brass "held in place" while the action is open? I'm working on a brass plug that has a groove for an o-ring that will create just enough friction to stay in place in case I am moving around with an open action.
Or did you just not worry about that?
Also, what O-ring did you end up using? Just a generic that fits permanently into the breechplug, then trim the brass extra to compensate?
Thanks!
PS, did you ever consider filling the wsm brass with lead then drilling out the primer pocket to eliminate the large air chamber between the primer and breechplug flash hole? Or is yours just open as-trimmed?