Gentlemen,
I'm having some serious issues with my 5R in .223 with factory ammo. All this rifles has seen is factory ammo (my first rifle incidentally), approximately 600 rounds worth.
To get right to the point here, I shoot this rifle infrequently so this issue is about 3 years and ~200 rounds in the making.
Right off the hop i'd like to admit fault. When I started to notice funniness with the primers I knew something was up but didn't take action and just let things play out while I observed. The major reason being the load that started the trouble were Sako Gamehead 55gr. soft points and the accuracy they were giving me was phenomenal. At 100 yards rounds were going into the same hole and I was consistently shooting .25 MOA groups. This was far in excess of any accuracy I had previously been able to achieve, and especially with buddies around to impress the temptation to continue to use that load made me complacent. This was before I had started to reload at all, one would hope i'd know better now. Not proud of this but no ego, just the facts.
Before I had shot the Sako I had shot about 400 rounds of assorted factory ammo over a few years, mainly cheap stuff because I was just getting into shooting (winchester white box mainly, some American Eagle), but moving into more premium ammo like Hornady and Nosler as I progressed. Looking back through all my brass from that period it all looks fine, I was having intermitent problems with light primer strikes with some of it right from the beginning but it was sporadic and they all went bang the second time through.
The issues started with the Sako (rounds not presented in order shot, they were all picked up later);
The rounds all functioned and fired fine. Extraction was nice and smooth, other than the primers nothing out of the ordinary on the brass and while in retrospect some of those primers are clearly pierced I there was no gas blow by felt or seen.
In between shooting some of the Sako, I shot some Hornady V-MAX 55gr. The primers on those appeared fine, although upon closer examination now a couple of them at least were slightly cratered (placed bottom left);
The real concern started when I brought this rifle out again (after a year or so) to ring some steel with some generic .223 ammo. I got a couple rounds off, and initially after examining my first three cases or so quickly the primers looked OK. And indeed, a few brass out of this batch do look OK. I then proceeded to shoot most of the rest of two boxes pretty rapidly when I noticed smoke leaking from around the bolt after a shot. Upon extracting it I noticed the primer was pierced, and examining the brass that was strewn about I noticed that a few other primers (4!) were pierced and most of the rest of them were cratered/bulging. I only had three rounds left in the box at that point, so I didn't shoot those.
I did however shoot some other Hornady Varmint Express (40gr.) I had lying around, and while not pictured those primers looked perfectly fine.
Also included for your consideration is some Hornady Superperformance I shot before and during the above events (i'm not sure which box is which, both pictured), and some Winchester Whitebox from way back.
My questions are what likely originally happened/could have happened to start off the issues, what happened when I continued to shoot the rifle, and what needs to be done now to correct the problem.
Here are a couple pics of the bolthead;
What are everyone's thoughts on this? Other than the fact that i'm a moron, I know that (although you can still tell me that if you want).