Quote:
Originally posted by Catfish
There is no need for the hotter primer with the .308 case, but they can be used. From all I have read and been told since 1966 when I started loading my own, the you will get a presure increase with mag. primers, and you should drop 1 gn. of powder from the recomanded starting load when working up a load. I have never used a strain gage so I can go only on what I have heard and seen by looking for presure signs, but have done that many times and never had a starting load that was hot.
I did due some expermenting with velosities and primers this summer in a .22-6mm. What I found in that round was very interesting. Useing the same load except for the primer, I compaired 5 ifferent primers. Different brands and some standard and some mag. Takeing the average of 5 rounds from each load there was only 51 fps., as I recall, from the fastest to the slowest with a round that was running between 3,450 and 3,500 fps. That was 1 gun with a round that is definately over bore.
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Catfish, I usually get 50 f/s variatioins in my 3000-3800 f/s rifle chrono strings more often than not. If I'm reading you correctly, you're saying that the variation in chamber pressures is PROBABLY (and probably being a key word) not much, no matter what primer you use, at least in that .22-6mm. Doesn't Denton say the same thing in his posts on the subject? I personally don't use mag primers unless the powder being used is IMR 4831 or slower and sometimes with ball powders in rifle cases and with all full magnum loads in pistols. I've never really studied this situation the way you and Denton have, but have the impression that what you say is entirely correct, at least that's been my experience.
Rev