Jason, Jim is right, I should have said that if you are going to the trouble of sending test samples to Armbrust or testing yourself with the equipment I recommended, you should purchase a large quantity of the same lot that you tested. This would ensure you have good data for that lot.
The point Greg makes is a good one to remember; manufacturers of ammo typically do not have a pressure goal/specification that they load to except to be under the SAAMI limit (for US makers). Their goal is to meet the velocity specified for the load. They acquire large lots of powder that are not controlled in the same manner that consumer powders are controlled and since they can switch powders at their discretion, pressures for a particular product line of shells may vary enough to be of concern.
For what it's worth, the pressures I've measured with my equipment have been as much as 1000 psi different than reloading manuals have stated for the particular load. Some have been very close. IMO, loading manuals will keep you safe, but pressures may still be further off than most would like to believe.
