Originally Posted by ldholton
Originally Posted by ChrisF
There's a thread running on the highpower board I frequent most often, NationalMatch.us. The question was what neck tension for 600 yard loads? Bearing in mind that we're often shooting AR based autoloaders, most of the responses are 0.002 or 0.003. One of the sports big dogs said he's using 0.001 but he's a bolt gun shooter. It sounds like he has tested a bit with seating force, neck "tension" and 600 yard accuracy as his correlated variables. I'm interested to see what data he shares.

In this area, it seems that "neck tension" (as a measurement of sizing below bullet diameter), is the defacto measure...but I would think seating force would be more relevant. Similarly, SD seems to be a common output variable, but I think we'd all agree that group size and consistency trumps all.

I've got a strain based seating force gauge that I've never used. Apparently "Big Dog" has one as well that's he's capturing data with.

That thread has me thinking that when Richard Lee was touting his Factory Crimp Die as producing more accurate ammo, was it because of a more consistent "bullet pull" force (opposite approach of achieving consistency vs annealing and reducing neck sizing)?
excellent post..

no way for a little guy like me to prove everything but I've always been of the opinion neck tension is only a part of a good formula the condition of brass and how much spring back how hard it is and all can make a difference. it's getting the bullets to release from the case at the same amount of pressure is one key the more accurate loads..
Consistent pull force is really the quantity of interest, but it’s difficult for most handloaders to measure directly.