What is the headspace datum line measurement for the 338 Lapua? I hear the .420 "E" bushing for the Hornady tool is not correct? Should be .45....something?
Roger that. I'm bumping shoulders back .002 and wasn't quite sure if it made any difference at all where the measurement is taken. Thanks.
Thanks Gary. I also base my calculations off fired brass from that specific chamber, if I have 50 fired cases I measure ALL of them and line them up in files, then whichever file has the most cases I base my shoulder setback on those. I also dislike trimming and measure my chamber lengths with the Sinclair gadget in a shortened case.
I'll measure up my fired cases with your OD neck vs. shoulder average and see where that puts the datum line for may cases.
I just have a hard time using the longest measurement. Example ( and it usually is about this way) I fire 50 and have 40 in stack "a", 8 short in stack "b" and 2 long in stack "c". I'll remeasure a few times and even use a second caliper. I can understand how some cases can be shorter but not the "longer than the chamber" ones. Maybe it's because we cam the bolt open quickly and eject them real hot. Who knows. You've shot thousands or hundreds of rounds in your rifle and know that measurement but a few long ones always pop up.