Just a word of caution regarding nato 7.62 brass.

[drone]

I recently bought another 308 win rifle and loaded up some GGG match brass. This is 7.62 nato brass and there's nowt wrong with that but one has to remove the swaged in metal surrounding the primer pocket prior to reloading.

This image shows the case head which has already been reamed using the lyman LR reaming tool. The annular ring showing where the case has been swaged is still clearly visible.
I wanted to check the velocity of the two brands of primers I have, magtech and S&B so I loaded up10 of these cases with the S&B, which were the last 10 I had then wanted to reload 20 with the magtech. I use a Lee hand held priming tool and there was no way I could get the magtech primers into my prepped cases. I had to use my lyman case deburring tool to cut the brass back, even then the primers were significantly harder to squeeze in when compared to the 10 S&B that I primed the previous 10 with.
Also the primers looked to be much deeper in the case. I have previously loaded 100 + 30/30 cases with these primers and experienced no problems whatsoever.
At the range the magtech primers would not fire whereas the S&B ones did. I retained one of the S&B cartridges unfired and measured the depth of the face of the primer below case head, 0.002"
for the S&B, for the magtech 0.006".
I pulled all the bullets and powder from the magtech cases and, after warning the wife couldn't make any of them fire, after a short while I deprimed the cases in question and found that in every case the anvil had come out of the cup in EVERY case. At this point I blamed myself so I resized some federal cases put the anvils back in the cups and inserted 5 into the 5, F C brass i'd prepped using the lee primer putter inner on my classic turret press, after warning the wife again, all 5 of these primers fired normally in the federal brass without bullets or powder BTW thus negating my negative waves about rifle headspace.
In hindsight I should have realised all was not well with the brass and the force needed to seat the primers, not to mention the extra depth of the primer in the pocket.
I thought I wonder if it was the hand tool? so I primed 5 of the GGG brass using the same method as above also using primers I'd just decapped from the cases.
The primers were no 0.002" beneath the casehead and they all went bang.
I've slept on it and the only conclusion I can come up with is as follows, the S&B primers have 3 legs to the anvil, the Magtech don't.

The magtech primer is on the left in both instances, The magtech primer was fired out of the gun in question but the S&B one wasn't.
I can't begin to speculate what has transpired here other than I'm at fault but, having said that I've just primed some new win 30/30 brass with the Magtech primers and they were quite hard to install BUT the primers are just about 0.002" down from the vase head.
Does anyone have any experience of a similar issue? My immediate reaction is to scrap the GGG brass.

[drone]

I just miked the two primers, the Magtech is 5.36mm in diameter, the S&B 5.32 or about 0.001" smaller in diameter, don't know what to make of that at the mo.

[Ballistol]

SAAMI information.

[Ballistol]

I find these gauges handy when checking primer pockets.

[rox]

Does anyone have any experience of a similar issue? My immediate reaction is to scrap the GGG brass.

I've loaded 10s of thousands of de-crimped GGG Imperial cases with primers including Fed, CCI, Ginex, Murom & Magtech. None of them have given any issues with ignition, including use in a rifle at the upper headspace limit. The largest diameter of these primers is the Ginex, at 5.370mm.

I'm curious why your conclusion is to scrap the brass, especially when you seem to have narrowed it down to using the larger & stiffer primers with a hand priming tool that struggles to seat them. It seems likely that these primers weren't bottomed-out.

Of course, the de-crimping could also be contributing to the problem; it's hard to comment given the photo quality, but it looks possible that the pocket is chamfered on one side, but not the other (perhaps leaving some crimp intact), but that could just be reflections, photo angle & general photo quality.

[drone]

Thanks for the info. Re the photo of the case head, this was after the application of the lyman pocket reamer but before using the lyman case mouth chamfering tool. I took a picture of the loaded ammo just before I salvaged them and it should be nearby, I think it will reassure one that the primers are deep enough, too deep according to my range control officer and I have to agree with him.

As I mentioned, all the primers when removed from the cases the anvils fell out; About six months ago I removed many primers prior to offering the brass for sale and they were S&B primers, none of those exhibited the lost anvil syndrome. I subsequently bought a new to me 308 and decided to re-use the cases after recycling the S&B salvaged ones in my 30/30, all bar 10 that is.
Rox pointed out that it looked as though the reaming had been carried out non-concentrically, that's quite possible and I wondered if it managed to ping the anvil out when I was seating the primers, I don't know is the answer.
The design of the magtech primer is different to my norm, being a staunch user of S&B in recent years but the spacer in between the anvil and priming compound in the magtech primer cup looks like white polyethylene as opposed to a small wad of whatever in the S&B variety, though I've only ever seen those after firing, they all but disintegrate upon disassembly then as opposed to the magtech which still resembles polyethylene though much blackened. ( I read an american method of refilling primers and I wanted to convince myself it was possible.)
I've reloaded many cases large and small rifle and pistol primers,as per the case requirement, and never had this happen before, I won't suggest I'm vastly experienced, I'm not but I've walked around the block over the last 6 decades and it definitely is a first for me.
I can only apologise for the image quality, I blame my i phone. I can only hope this image is adequately clear.
Finally, yesterday evening, I sprayed brake cleaner through the firing pin at both ends of the bolt then purged with compressed air then dribbled silicon oil down both sides. I THINK the pin eased up but I won't be able to tell until after Xmas as family commitments keep me from trying out loaded ammo on one of my permissions. Let's just say on once fired primers reinserted into resized cases the dent in the primer increased when dry firing.
Watch this space, I probably won't come up with a cause but hopefully a cure as the thought of stripping down my BLR fills me with apprehension.

[rox]

Have you measured the height of the Magtech primers and compared with other types? Also the pocket depth of the GGG brass vs other brand? and the seated depth from face of case head?

I don't have any Magtech samples to measure but this page gives the height as 0.120". Compare with the following that I have to hand:

0.125" Ginex
0.127" CCI200
0.128" 210M
0.125" KVB-7

Maybe there is some combination of the shallower primer, rifle headspace, firing-pin protrusion, placement of the case shoulder that is causing the issue.

Ultimately, if the pocket is in-spec and no deeper than other brass, then how can the case be responsible for the problem?
From a quick measurement I don't see that GGG pockets are any deeper than Lapua LR brass, for example.

I might have expected that seating on-press (more force) might solve the issue because the primers are being bottomed-out, but by the sound of it they were seated less deep (0.002" below face of case-head) and yet worked - if I am understanding your post correctly.

[billgatese30]

When you reamed the primer pocket, did you cut it deeper?

[mag41uk]

I have noticed that magtech primers are a tight fit in GGG. And also some Hornady. CCI were fine. The magtech work fine in RWS brass.
You only need primers at the larger diameter coupled with primer pockets at the smaller diameter, throw in a ring crimp and things can become tricky.
I use a 45 degree woodworking chamfer bit in a pillar drill at low speed to remove the GGG and Hornady crimps. Works just fine.
Or buy one of the press mounted pocket swagers if you have loads of GGG brass.
They are easier to work with after that first reload too.
And I have seen the anvils fall out of magtech primers that have been pushed back out. They really are a one way thing.
I would be measuring depth of primer pocket and depth of the magtech primer to ascertain that the require depth tolerance can be met.

[drone]

Rox, I measured the depth of the primer pockets in several fired pieces of brass, GGG came out at 0.129" just after the one firing, Federal was 0.128" after multiple (maybe as much as 10 firings)

Bill, I don't think I deepened the pocket, regrettably I sold all the little nick nacks I had for 308 when I sold my rifle chambered for it.

Mag 41
there's an image of the tool I used to chamfer the edges of the primer pockets, after the initial ream job when I felt the force required to seat the primers was excessive, it eased up a little but nowhere near as light as the force needed to seat the same primers in federal cases.

When I get a moment I'll measure how long/thick the primers themselves are.
BTW thank you for that corroborative information.
I'll try some GGG cases with primers only t see if the freeing up of the firing pin I carried out last night was effective, hopefully tomorrow.