Sign of pressure or...?

[jmayton]

So I have a good load in .223 that I like and shoots well in both my AR and my Handi-Rifle.  It's a 55 Sierra SPBT pushed by 20.9 grains of H4198.  I full length size my brass and trim to length.  This last lot was used Remington brass.  When I developed the load I was using Winchester primers, but I've switched to CCI (mainly because I can find them in stock).  I've noticed with the CCI primers most of them are backing out of the primer pocket.  They've always been flattened a bit, but with them backing out, do I have excessive pressure or is this because of the change in primer or what?  I don't see any other signs of pressure, but this has got me a bit worried.

[stimpylu32]

It could be a number of things that are causing this to happen , one is that when you switched primers your pressure has risen to a higher level or it could have fallen to the point were the primers are not be reseated as the case is pushed back against the breach face .

Some others are that the cups on the CCI's are harder and not gripping the pocket as well the softer Winchester primers did , or that the primer pockets on the Remington cases are oversized and allowing the primers to work loose .

When you switched primers did you back off on the load and work back up or did you just go with the same powder charge ? The reason I ask is that the Rem may have a smaller case cap than the Win and thus increase pressures due to less space to work with .

stimpy

[Catfish]

That should not be a hot load, BUT MAKE SURE. With .223 cases it is not uncommon to find cases with primer loose primer pockets if you buy used brass. I lost a coyote this fall because I blowed a primer clear out of the pocket and it jammed the action in my AR. I did a check and found some rounds that the primers had fallen out of. How did the primers feel when seating them?

[jmayton]

Stimpy, I kept the same load, just changed primers.

Catfish, the primers felt about the same when seating.  I had to use moderate pressure...they didn't just slide in.

My thought is that it's a combination of slightly oversized primer pockets with the Rem brass and slick primers not gripping.  I think I'll try some Win brass and see what happens. 

[Lone Star]

Protruding primers are almost always due to excess headspace, NOT to excess pressure.  You must have changed the FL sizing die setting, changed the press, changed the load/powder/lot, or are using short-headspaced brass (maybe switching brass from one rifle to the other...).  It is hard to believe that simply changing primers lowered the chamber pressure enough to get primer protrusion.   



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[jmayton]

Lone Star, of the things you listed there is only one that could be culprit.  I had to turn down my FL sizing die about 1/2 turn so that the cases would stop sticking in my AR.  But that change was done before I changed primers. 

Another thing to this though, is that I've only noticed the protruding primers in my handi, not my AR.  That's not to say that they are not  doing it in the AR, I just haven't shot it enough at the range lately to know.  Since it's happening in the Handi would the culprit most likely be excess headspace then?

[Lone Star]

If you are using cases sized in the same FL die/setting, then my guess is that the Handi has longer headspace than the AR does.  Your Handi loads are not particularly hot or the case head would move back into contact with the standing breach with no protruding primer. 

Hot loads don't cause protruding primers, low pressure loads do.....another thing to consider if the loads are different.



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[jmayton]

No, I use the same load for both rifles.  The only thing that has changed is the primer.  I'll take a look at some cases fired from the AR when I get a chance.