primer seating

[Arnie]

I have a question on primer seating .First off i have been doing the same thing for many years in my black powder single shot rifles with no problems .Assuming the rifle primer pocket is .132 deep and you put a pistol primer that measures .123 thick across a caliper and seat it with a Lee auto prime and then push it back out i get the measurement of .109 to .111 thick .This leaves a depth into the pocket of about .023 .Now if i could seat this primer with out crushing the anvil intot the cup it would remain .123 thick and only be .009 below the head .I have tried seating these with out crushing but the feel just isnt there to me . My question is are you supposed to crush the anvil or not ?And if not there seems to be a need for a seating tool that stops on the head of the case with a raised portion in my case of .009 thats primer diameter and a bigger around area that would hit the head of the case .Arnie

[floodgate]

Arnie:

ALL the instructions I have read on primer seating (including an Australian handloading book from 1970 Mick just sent me I was reading through this evening) point out that the primers are shipped with the anvil protruding slightly from the bottom of the cup. Ideally, when primer and pocket are properly matched (as they are NOT with a Large Pistol primer in the deeper Large Rifle pocket), seating the primer 0.001" - 0.003" or so below the case head seats the cup to the bottom of the pocket, and forces the anvil into the priming mix just the right amount to "sensitize" it for optimum ignition when the firing pin whacks it.

floodgate

[monadnock#5]

The primer seating instructions that I like best comes from "Handloading for Competition" by Zediker. When the primer cup is bottomed in the case, there is still a gap between the anvil and the wafer. As such you should bottom the primer and compress it just a bit more. How much more? To determine that measurement you would need a stand and indicator, and measure to the fourth place to the right of the decimal point. Not practical you say, I agree.

Therefore, bottom your primers on the web of the case, and compress it a bit more, with the understanding that deforming the primer in any way is a BAD thing. If you follow these instructions and come up with a primed case that looks as good as a factory primed case, you're golden. The only priming system that I am personally aware of (I haven't used them all) that has the sensitivity for this operation is the Lee hand held Auto-Prime.

Ken