If using Lapua brass, do you guys ream the additional length into the body of the chamber and fire form,or trim the additional length off the case
Could you elaborate on what you're asking? I presume you're talking about a 338 Whisper, but what Lapua cartridge? Are you talking about making the equivalent of a 338/7mmBR out of a 308 case? I'm confused too.
Got it figured out Lou, Lapua brass was just short of .040 longer than the Rem 7 BR brass in the neck....trimmed the brass and it worked with the BR headspace guage.