Home Forums Reloading Big Game Rifles Neck size 7.65 Arg using 303 die

So a buddy of mine has a 7.65 Arg and dropped off boxes of once fired 7.65x53 brass along with a 2-die Lyman set consisting of a FL sizer and a seater.

I would like to neck size these cases but cannot find a Lee collet die for this round.

I am told I could use a 303 collet die for this but am am curious as to the process. Would I somehow use the FL Lyman die to de-prime without sizing by just backing off the die until it barely popped the primer?

If that works, then how do I collect size using the 303 properly? Rather not spend the money on a Lyman or other neck sizer for the tiny bit of reloading needed.

Then of course there are which bullets . If I tell him to use 303 bullets because the Argy is .311 you know he is going to go cross eyed.

Awaiting learned responses.