gunner,
Apparently my post on why pressures vary a lot in 7x57s with the SAME load was too long for members to read: Here's the pertinent part:
"I've owned several 7x57s made by Ruger, and throats ranged in length from the present SAAMI throat (which is relatively short) to one perhaps even longer than the original military throat. Plus, plenty of other companies have come up with their own variations. I had one custom 7x57 made by a company that uses a reamer with a throat even shorter than the SAAMI specifications. As a result of all this, there is no way the same powder charges are going to produce similar results in all 7x57s. I've seen as much as three grains difference in the amount of IMR4350 required to produce the same velocity with 140-grain bullets."
