Ruptured Primer

[jr_roosa]

I was shooting at my highpower match today with my Garand (30-06) and I had two primers blow out at the edge. I was working with a new load and comparing it to an old load, and I had one blow in each batch.

The first load was 46gr of VVN150 with a 175 Grain Sierra Match King in Win brass with Win LR primers. This was the 5th firing on that batch of brass. Seating depth is fairly long, but still within mag length. This is my "Garand Safe" 600yd load. This one had just the smallest leak at the edge of one primer in about 24 shots. I've shot this load for years and never noticed a problem before. Pressure signs have always been weird with my Garand since it seems like the primer gets pushed back in on firing a little, even with super light loads.

I got a new Garand Gear plug that should let me run closer to commercial .30-06 loads, and I have a new load that is completely the same except I worked up to 49gr of VV N-150. This is below the VV published max for 190gr match kings, and gets 2620fps, which isn't lightning fast or anything. One out of 22 of these blew at the edge and pitted the bolt face. No cratering, the primer pocket is still tight, and the other fired brass all looks normal. Consistent ejection, very accurate load (I shot my 2nd best score to date with these first time out), and the extreme spreads over the chrony during load development was really good.

Any ideas? Too close to max and the usual variability blew one primer? Weak primer? Something else?

I'm baffled. I might just work back down a grain just in case things are too close to the top.

-J.

 

[243winxb]

I worked up to 49gr of VV N-150. This is below the VV published max for 190gr match kings, and gets 2620fps,

VV list 2516 fps. Maybe try different primers? http://s338.photobucket.com/user/joe1944usa/library/Firearms%20%20and%20%20Reloading/Primer%20Gas%20Leak

 

[jr_roosa]

VV list 2516 fps.

Yes, for 190s, this was with 175s.

 

[243winxb]

Ok, 175s. Bad primers will blow out even at low pressure.

 

[rcmodel]

Were you using GI 30-06 brass with reamed primer pockets??

An off-center ream, or too deep ream would be my first WAG.

rc

 

[jr_roosa]

Nope. Winchester commercial brass. 5th firing.

I'm thinking bad juju or something. Or slight overcharge somehow.

J.

 

[jr_roosa]

Also same primers I always use. 3000 rounds through this rifle and only one pockmark in bolt face.

J.

 

[edfardos]

All of my breach/bolt/recoil face pock marks were with winchester primers. Likely just a bad lot. I chucked 500 or so. RP brass will exacerbate hard/brittle primers too.


Edfardos

 

[rg1]

I've only had one primer that had a pin hole leak in the radius of the primer cup. From a bolt rifle it blew gas and some small particles back towards my face. Had on glasses. Does your Win LR primer look like this one posted yesterday here: http://forum.snipershide.com/snipers-hide-reloading/190170-pressure-bad-brass.html
I think it's just a case of bad metal that is weakened by the cup drawing process and it must leave a thin section at the primer edge?

 

[jr_roosa]

Exactly like that. I didn't take any pictures because I decapped it to verify the leak and that the primer pocket wasn't stretched.

Hopefully it's a one off thing. If I get another ill see if winchester will replace the batch and maybe pony up for a new bolt?

J.

 

[Edarnold]

Exactly like that. I didn't take any pictures because I decapped it to verify the leak and that the primer pocket wasn't stretched.

Hopefully it's a one off thing. If I get another ill see if winchester will replace the batch and maybe pony up for a new bolt?

J.

Since you are handloading, and the bullets and powder and load data are from other manufacturers, I would guess your chances of Winchester compensating you are something less than zero. Also, with due respect, what are you getting from that extra three grains of powder that justifies pushing the maximum? I load for my M1A, and have never seen any reason to push beyond the loads specifically rated for that design. The action will hold very high pressures safely, but the wear and tear on the moving parts just makes hot loads unattractive.

 

[ArchAngelCD]

It just might be the Winchester primers. I use CCI primers mostly and never had one blow like that. (and not just the CCI#34 primers, CCI-200 & CCI-250 primers)

 

[jr_roosa]

what are you getting from that extra three grains of powder that justifies pushing the maximum?

I cut my extreme spread in half and increased my 600 yard scores by about 20 points with noticeably lower vertical spread.

Not worth torching the bolt though.

I had one rupture with a much lower load too, about 4 grains below max with 4895. This never happened with this load over maybe 1000 rounds in this rifle.

After a search it looks like there is a rash of these from winchester primers bought last fall.

J.

 

[emb]

I had a Fed 215 blow like that in a 300 RUM. I was shooting a rather mild target load. I called Federal and sent them the brass with the primers intact and the lot number. They told me that the primers had been exposed to ammonia on their end-not mine. They assured it wasn't me or anything I did. Federal suggested that I dispose of that lot of primers and not shoot the ammo that I had loaded using them. They sent me 5000 new primers. Way more than I already had in stock.

 

[fguffey]

jr-roosa, I do not know what you are attempting to accomplish, you are on the fifth firing, the next time you fire those cases will be the sixth. Before I fire a rifle once I know the length of the chamber from the shoulder/datum to the bolt face, I know the length of the case from the shoulder/datum to the case head, meaning I know the effect the chamber is going to have on the case when fired.

I am the fan of cutting down on all that case travel, I do not want my case heads sliding back and forth, I discourage primers from backing out and reseating. When the primer backs out there is a chance the primer does not have primer pocket support, if I had leaky primers I would carefully examine them to determine if the primer leaked while unsupported, the primer is supported by the primer pocket and bolt face except when the case and primer separate.

F. Guffey

 

[MtnCreek]

After a search it looks like there is a rash of these from winchester primers bought last fall.

Yep. I started using mine for below starting charge loads in 6.5x55 and they've been fine at that. In .308win & .300wm they were blowing about 1:5 primers. I switched to CCI's and they've been doing fine.

 

[jr_roosa]

I switched to CCI's and they've been doing fine.

I have 5000 more Win LR primers in the cabinet. Who knows when CCIs will be available again

I do not know what you are attempting to accomplish, you are on the fifth firing, the next time you fire those cases will be the sixth. Before I fire a rifle once I know the length of the chamber from the shoulder/datum to the bolt face, I know the length of the case from the shoulder/datum to the case head, meaning I know the effect the chamber is going to have on the case when fired.

Me too. Here is a case sized to 0.001" shorter than the longest case that will fit my chamber and allow the bolt lug to go all the way to the rail:


Untitled by jr_roosa, on Flickr

Here's after chambering it from a SLED one time in my Garand:


Untitled by jr_roosa, on Flickr

I reliably get about 0.004" setback of the shoulder from chambering. This gives me about 0.005" of excess space. I am tempted to size a batch to 0.004" longer than my chamber and see what the primers look like, but I am afraid of an out-of-battery discharge.

Hatcher writes about this effect at length in his Notebook on pages 244-245, and he even describes up to 0.012" shortening of a round chambered into a Springfield 1903 with normal force, even though the round was originally shorter than the rifle chamber.

 

[jr_roosa]

BTW, here is a fired case from the same batch. None of these primers blew.

This one is 0.005" longer than the chamber. So, everytime I fire a case, I get about 0.010 case stretch, but I would guess half of that is on firing as the case head is pushed back against the boltface, and the other half is stretching on extraction. This is enough to ruin commercial Winchester brass in about 4 to 5 firings. HXP is going strong at 6, although the rims are a little worse for wear.


Untitled by jr_roosa, on Flickr

 

[243winxb]

Hatcher"s Notebook Link

Hatcher writes about this effect at length in his Notebook on pages 244-245,

Available here. http://www.castpics.net/subsite2/ClassicWorks/Hatchers%20Notebook.pdf 74MB down load. Large.

 

[ranger335v]

It's a defective primer cup, not excessive pressdure as such. Primer makers buy rolls of sheet brass from suppiers that are supposed to insure the alloy and thickness, the cups are stamped out on automated machinery. 'Trash' inclusions in the metal are hidden so no one can know they're there until the defects blow out and no one primer maker is any more or less likely to experience it than any other and it only matter when it's on the small cup radius where they have no support.

 

[jr_roosa]

Random failure is Kinda what I'm figuring, but I am going to work back down a little if only to minimize stress on the gun and to have a larger safety margin. It's odd to have two in one day after never noticing it before.

Also 30-06 isn't a super high pressure round, and LR primers seem to be acceptable with higher pressure rounds than that.

J.

 

[jr_roosa]

Update:

Blew another one. This one was on my M2 ball equivalent loads: 48gr of I4895 with Sierra 150 grain FMJBT seated to the cannelure @ 2700 FPS. This was in a different Garand, so now I have pock marks on 2 Garand bolts. My own damned fault hoping it was a fluke.

Again, not a hot load. It's actually the starting load on the IMR website, and it's 0.5gr less than the loads given in John Clarke's article on reloading for the Garand.

This is 3 blown primers in 3 different loads in 2 different rifles in the first 100 primers from the box. One of the pierced primers (a very small crack) might have been from the last of the previous brick of primers, but the 2 bigger ones are from this batch for sure.

Winchester called and left a message yesterday. I gotta call them back and chat.

-J.

Postscript: I should add, these were the last 10 rounds left from a previous batch that I was using to test out and zero a new Garand in preparation for a garand match this Sunday. I haven't loaded up any more of the suspect primers. Also, I intend to ask Winchester if my next 2 boxes of primers are from a suspect lot before I load up a batch for the weekend match.

I still have about 35 rounds left from the long range load that I think I'm going to have to pull and decap. What a pain.

 

[Slamfire]

In 1999 Winchester changed their primers from nickel plated to a brass finish. I called them up and asked what else they did. I was told that Winchester had redesigned its product line to make primers more sensitive to “combat off center firing pin hits”.
At the time I was shooting Across the Course service rifle with most of the rounds coming out of AR’s. I also shot match rifle on an AR15 action. The brass finish WSR pierced with loads that never bothered the old nickel plated WSR. I ate up a hand full of firing pins before I got the loads reduced enough , cutting a half grain at a time, to reduce primer piercing. But the velocities were not what I wanted so I used the last of those brass WSR for rock busting ammunition and used CCI #41’s exclusively after that. CCI #41’s did not pierce and shot well.

I believe what you are seeing is the same issue but with brass finish WLR's. Probably the primer cups are thin, maybe not cold worked to a greater hardness, and your primers are piercing.

I do not recommend “more sensitive” primers in the Garand/m1a/M1 carbine. These mechanisms have a free floating firing pin that rebounds off the primer. The military controlled slamfire rates by matching primer insensitivity to firing pin kinetic energy. Military primers are less sensitive for a reason and you continue to use “more sensitive” primers do not be surprised if you have an inbattery, or worse, an out of battery slamfire.

 

[docsleepy]

Hey, great thread! I learned a lot.

Can you tell me where to get those case comparator tools to fit on your calipers? I have a hornady bullet ogive comparator but not a case comparator. Never saw that before.


Edit: nevermind, I went to the midway site and found them immediately. Alas they're out of stock! But I never knew this existed, your thread helped a lot.

 

[jr_roosa]

I believe what you are seeing is the same issue but with brass finish WLR's. Probably the primer cups are thin, maybe not cold worked to a greater hardness, and your primers are piercing.

I agree, and I am tempted to move to the CCIs. I haven't had any pierce at the firing pin indentation though. There's a photo below. Unfortuntately I have 2000 WLRs in the cabinet excluding the bad batch with 900 left, and I bet that Winchester's solution to my problem is going to be to send me several thousand more.

I have been cognizant of the slamfire issue, and I've been good for 3000 rounds. I certainly won't touch a federal primer for this reason.

Can you tell me where to get those case comparator tools to fit on your calipers?

They are a game changer. I measure each resized case, which started after I had a batch where the first few looked good and the last 50 were almost all too long, which I figured out after they were complete. I think that reloading for an autoloader without them is foolish.

You should also get the bullet comparator bushings for the calibers you load. They make measuring seating depth much more consistent. I never knew how irregular the bullet ogive was.

Here is the primer from last night.


Untitled by jr_roosa, on Flickr