Then stick with the .270 AI.Semi conventional
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The bullets have been a large variety of 140gr to date.
130's and 150's not so much.
I'm really not a fan of heavies in .277.
I do however see the advantage in BC with added weight/length/solid-mono.
I've just been stuck in conventional 1:10 twist since the 70's
I suppose that if I ever got a quicker twist I'd be right in there pitching 165's
I'm looking at the WSM because I have a confusion of LR/AR-308 parts and a lathe ;-)
I should probably forgo any discussion about the .270 WSM and just neck a .308 to .277 and take out the body taper and sharpen the shoulder. In essence, 277-08 AI
Did you mean .540" +/-?A fair portion of my 270 brass started life as 30-06 LC
Too bad the WSM uses a .505 face :-/
It's not like I have a glut of 404 Jeffery around.
So as above, .277-08 AI ?
Good luck with your .27 chambering endeavor.