10-05-2024, 12:27 AM
I see what you mean now. I usually don't worry about shoulder datums b/c I have my dies set, and setbacks are already set along with. I have potentially 5-6 Arc's I load for/could load for (not all are in rotation right now), and I'm not ocd enough to have a resizing die setup for each one, I found one that moves the should back 005 or so for all of them... so base to tip (what I'm using now) doesn't vary much. I should probably confess that for lead tips and even some poly's, an OAL can vary by +/- 0.003, sometimes the sierras (lead) go +/-0.004. The only mfr I've found that can show me loads +/- 0.001 are the nosler ones... so for me if I have cartridges of +/- typically 0.003 I use load lengths accordingly, so there isn't any problem of winding up in the lands or anything (not my cup of tea, others may want to do that and that's ok...).
Edit to add: since this is all real world, a person will pretty much always find some variances in virtually all measurements... so if I were to check my shoulder setbacks after a resize I would find a 0.001-0.002 delta from one case to another... with my tools that is within a combined error tolerance. So for me I'm comfortable operating there.
Edit to add: since this is all real world, a person will pretty much always find some variances in virtually all measurements... so if I were to check my shoulder setbacks after a resize I would find a 0.001-0.002 delta from one case to another... with my tools that is within a combined error tolerance. So for me I'm comfortable operating there.