UH-OH...Primers backing out.

DasJager

DasJager

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***I thought about posting this in the Reloading section but because of the specific nature of the question I thought it better here...

So I loaded up some hand loads for my M305 and went to the range this past weekend. They all functioned 100% and accuracy was a noticeable improvement. One thing I noticed right off the bat though was that it didn't seem to be kicking the brass out like it did with other factory rounds (not as far). Then after inspecting a few spent casings I noticed a couple of them had the primer protruding out from the pocket just a wee bit. No cratering or residue burns around the primer. I first thought it may have been a headspace issue but did some reading and discovered that it could be caused by light loads as well (I'm using 40gr of VARGET over 150gr pills, which I didn't thing was on the light side according to my Hornady Handbook). It was new brass. They only variable I can think of is the USGI gas assy I installed recently (first thing I thought of with the brass not ejecting as vigorously) but I made sure the ports were lined up and shimmed the assy.

Peculiar it is. Any thoughts?
 
Anytime I've seen backed out primers, it was a exceptionally light charge versus bullet weight. Are you using NATO brass??

Never got it on handloads, but saw old IVI Imperial .30-30 back out primers in my Marlin, hence a low pressure charge, I assumed.

Smoked cases are another sign of incomplete chamber seal on intial pressure build with a light charge.
 
I use a chrony anytime I'm developing loads. The data is invaluable when doing a reality check back with the manual (i.e. are your speeds near what the manual listed?). Oh, and it's a good idea to use more than one manual as some manufacturers use different max for the same powder & bullet weight). That said, 40gr of Varget does seem on the light side (I've heard some guys say that even 44gr with 150gr bullets is a light load).
 
I've noticed that Hornady seems to stay on the conservative side with their max loads, but knowing that I usually start a little higher than min. I also reference My Laymen and Nosler manuals. I find that what is sometimes Hornadys max is not far off of Noslers min which can make you second guess yourself.

And no, I was not using NATO brass, it was new Remington R-P.

I'll have to try bumping up a full grain and then subsequently half grain at a time and see what takes place. As I mentioned it was not significant but enough to cause concern...I've never had it happen before. It happened twice noticeably out of twenty rounds.
 
I don't know if this will help, but I was curious so I looked it up.

Nosler Reloading Guide 6...............44.5 - 48.5c
Modern Reloading Lee 2nd Edition...44.0 - 47.0c
Hornady 7th Edition.....................35.9 - 44.9
Sierra Edition V 5th printing...........41.4 - 44.8
Speer Reloading Manual number 13..43.0 - 47.0c

good luck
 
My whelen was doing it until i used rem. primers for rem. brass. Ive used winchester primers in my .270 didnt matter what kind of brass
 
39g and 150g bullets has always been functional and accurate for me. I think it is too light step that up to 44 or more and the primers shouldnt back out
 
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