had my first blown primer today

[willysjeep134]

I just had not one but two blown primers in my 1917 eddystone. I shot quite a few rounds of cheap bosnian Hot Shot 30-06 150gr FMJ through the rifle first and it was grouping about 1.5 inches at 100 yards. So, I fired a few of my hand loaded 150 gr jsp boat tails and found they were striking higher than the FMJ stuff.

 Just for fun I decided to shoot a few PMP 165 gr soft points to see where they would hit when sighted for the 150's. Well, the first shot fired fine, the second one, a big puff of gray smoke came out of the bolt! I had just experienced my first bloan primer. So, after I took the bolt out and checked things over I tried to fire another one of these 165s, another big poof of smoke and another hole in a primer. I chambered another one of the cheap FMJs and it fired fine.

I was inspecting the PMP hulls and found out the first one had flown back around the firing pin, the other two were pierced. All of the 150 grainers I had shot showed no flattening or flowback.

What I am thinking is that the powder the PMP factory uses is more temperature sensitive than what I used in my hand loads or the stuff in the Hot Shot from Bosnia. By the time I got around to shooting the south african stuff the barrel was pretty hot, so I think the hot steel helped warm up the powder and make excessive pressure. None of the other loads showed any high pressure signs.

It was about 28 degrees and sunny when I was shooting, but I didn't wait for the barrel to cool down between shots, so i think that is why I had the blown primers. I will take the rest of these PMPs and shoot them off first next time and watch for high pressure.

[gunnut69]

Have you had the headspace checked.  Some rifles will blow primers when headspace is excessive.  The primer is pushed back out of the pocket by it's firing and as the pressure rises the front of the case grips the chamber and stretches to fit the chamber. If those PMP(?) cases were a bit on the short side it may be that you have a bit of headspace which combined with the short cases to create pieced primers.  Check inside the cases to see if an incipient head seperation ring is present.

[clodbuster]

Gunnut   In my ongoing attempt to understand headspace and associated issues:  Can excessive headspace condition be dealt with effectively by hand loading with neck sizing only on cases fired from the rifle in question or does the headspace problem result from a defect in some part of the gun?

[Racepres]

Ooooohhh Clodbuster I look forward to where this goes!!! Especially since I believe that a piece w/ bad headspace can be caused by more than one thing ... some worse than others. Back to primers ... once I had an entire lot of primers that were apparently "soft" they blew at really low pressures. Luckily they were small rifle primers and if used in mild 38 special loads they worked excellent.... gone now. Just saying that one never knows w/ something made by humans and their machines ... may not be "perfect" .       Marty

[willysjeep134]

I didn't have the headspace checked. The rifle was a gift from my uncle. It was a 1917 enfield eddystone, but a company in the 40's ground the ears of the reciever, polished the whole outside, blued it, put it in a fiddleback sporter stock, and jeweled the bolt and drilled and tapped for a scope. I figured it was probably safe, he did hunt with it for several years. Mabey I should have this checked out some time.

I had shot a full box of that PMP stuff out of it last fall with no ill effects. When I shot that box I was walking down to check the target between groups. I was also only shooting one box. I don't think the barrel was that hot.

These blown primers were probably from the same lot as the last box of them I shot. I bought 2 boxes right when I got the rifle just so I would have some around.  Mabey it was the heat, or maybey a few soft primers. I will look into the headspace.

[Racepres]

Checking the headspace is an excellent idea ... if it's good you will have purchased great piece of mind.... Having said that I saw on another post a poormans method    but those usually do not really provide piece of mind... Yea it is probably best to eliminate some possibilities ... BTW if those were my rounds I would pull the bullets, pop the primers (shoot em) and reload... blown primers can cause cumulative damage to the bolt face (mine kind of burned a tiny hole in the face next to the firing pin). Rifles are much more expensive than ammo.... $0.02..      Marty