Nephew -- experienced reloader, and every weekend tactical shooter -- inherited a very nice high condition Arisaka Carbine. I was picked out of a Japanese Armory in Tokyo by a relative and other than a ground Mum. We spent an afternoon doing a cleaning, and shiney bore, every thing fits and matches. He tried it out with the US commercial ammo that came with it: shoots bullets in groups

Sooo, as he is already a loader...he picked up dies, powder, bullets, etc and made some ammo...Took it too range, and an anomaly developed. At what appeared to be random occurrence, an ejected case would have a smeared primer strike, and a pin-hole 'burn-thru' on the edge of the primer.

No idea, other than unsubstantiated guesses -- so toss this out to The Assembled, in the hopes that it;s one of those "Oh, yeah....it one of THOSE things." Thanks for a lookover.

need a pic

be a day or so, and thanks for the request.

Things I would look at:
Bolt face
Firing pin tip and protrusion
Fit betwixt the two
Clear firing pin channel/main spring
Primer type
Brass type with respect to primer pocket
Flash hole size (reaching a bit)

Not much of the above would explain the 'pin hole at the edge' trouble. Just thinking of things which might affect the firing pin to 'smear' the indentation.

Going from memory (don't have an Arisaka), it's a '98 Mauser-ish design. It should retract the FP upon opening the bolt...at least I'm pretty sure it's cock-on-opening. That should negate any FP hang-up. Hmm...pictures should help.

y'r E-mail addy to marshgrrrl@yahoo.com -- and I can FWD to you. Thanks....some days an axe is more appropriate than a keyboard, regarding puter stuff.

Ariskas are generally very strong actions of high quality, but they are getting long in the tooth. If he did not have any issues with the factory ammo, I would suspect either his loads are hotter than the factory loads or the primers are softer. The first place I would check would be the bolt face and specifically the fit of the firing pin in the firing pin hole. If there is too much room around the firing pin it can move aside allowing the primer cup to flow into the gap. Have had this experience on older rifles before.

This is a picture of the primers. The one on the left was loaded with 30.5 grains of varget behind 139 grain FMJ bullet. The one on the right had 28 grains of Varget. This also happened once with some factory Norma ammo , which came with the rifle (at least 10 years old). I shot 2 more rounds loaded with 28 grains and none exhibited any signs of high pressure. I'm using brand new PPU brass ( resized and measured with micrometer), Winchester Large rifle primers and PPU 139 grain FMJ bullets. BTW i'm John's nephew.

You're linking to an image in your email account. Those images are protected and you can't link to them. You'll need to upload it to the server here. Use the UPLOAD button to the right of the window where you compose a message. If you can't get it to work, feel free to email me a copy and I'll be glad to insert it here for you.

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Thanks Paul, I just emailed you the picture. When I initially posted it I could see it so I thought it was OK. Thanks again .

With the code pointing to your email inbox, the system lets you see what you posted as you've got permission to see what's in there. But no one else can since it's in your email inbox. I just replaced the code with code that points to the picture on the server that hosts the forum. It should appear now for everyone. I took the liberty of trimming it down a bit so that it'd fit and so that the damage could be seen more clearly.

Those pics make me wonder if the blown section is always at the same orientation. That is, does it always blow out at, say, 3 o'clock in the chamber? Or does it blow at random spots around the chamber? If it's always at the same place, it would seem to indicate a low spot on the bolt face, perhaps.

I'd suggest you switch to CCI primers. They tend to be a bit harder. Shucks, they even have some "military grade" primers that are harder still for use in automatic rifles. We'll see what others more knowledgeable than myself have to say.

I know most people will think I'm crazy.

Ive seen a less drastic issue caused by the "loaded headspace" of the round being quite a bit shorter than the actual headspace of the chamber.

The round on the left even looks like a case head seperation unless it is a trick of the camara. - JM.

I'm thinking the only way a primer could blow in such a specific spot is a lack of support in said spot. That is strange for certain. The case on the right may even have a second, smaller breach at about 3 o'clock. FWIW, this is new to me.

He's an avid three-gunner, and my niece knows which end of gun goes bang, y-betcha. -- My grand-niece -- a very young Archer Princess, defends her Tree Fort Castle with the determination she inherited from the two of them.

I had let Steve know that this is a unique board, of some of the best souls to found on the 'net. As well, it is a no-BS place for shooting fact and knowledge. So, thank you for making him welcome, and someday y'all might see pics of a young lady out at his Club, runnin and gunnin' with the best of 'em.

Those cases go to the scrap dealer. I would have the rifle bolt face checked as the gases may well have cut into the bolt face; there may also already be something wrong with it. Headspace was mentioned and that should also be checked; try gradually sizing a case to find the point at which the bolt will close on the sized case, then measure the neck and compare to the cases you have already sized. Just some thoughts...

That is not what I was imagining from John's description, he was accurate with it, I was just imagining it differently.

I would very carefully inspect the bolt face for any defect, void, burr, whatever that could be having an effect on the edge of the primer. The load on the left definitely looks like there are pressure issues going on.

Another place to check would be the locking lugs on the bolt to make sure they have not been set back or distorted in some way, possibly by some former owner firing too hot loads in the rifle. It is not easy to inspect the bolt seats in the action, but if there is any distortion or damage to the bolt lugs, it can be assumed the seats are also damaged.

You said the cases were sized and checked with a micrometer, I would not recommend sizing cases based on the specifications listed in the manual, especially for an older firearm. I would size cases to fit your specific chamber by sizing them just enough for the bolt to close without being forced.

If the cases will fit into the chamber freely without being sized you may want to consider fire forming the brass by setting a bullet out far enough to engage the rifling and putting a suggested starting load, at most, under it. After firing you can measure the case to see how it compares to unfired brass to see if there is any significant difference.

Your current fired cases may not show actual headspace between bolt face and case shoulder because under pressure the case wall can expand fast enough to grip the chamber wall, not coming back fully to the bolt face until pressure in the case is low enough to not push the shoulder forward.

First of all, I won't claim to be an expert on anything, but I have many years experience with ONE particular Arisaka, and lots of reading/research about the things.

Arisakas commonly have oversize chambers; they were made with no regard for reloading. As a military rifle, reliable operation under battlefield conditions was the only consideration, and the cases were one-time-use only. The one I have was built in the mid 1930s and is as finely made as any rifle I have ever seen, but the cases that come out of it look like they were just short of blowing out. Norma factory ammo shows fired primers backed 'way out of the pockets, and a big bulge ahead of the case head. In order to reload for this rifle, I found I had to back the sizing die out until the die shoulder just barely kisses the shoulder of the fired case, and does not push the case shoulder back at all. Then the primers will stay in place. Cases still expand a bunch, but there's enough taper to the case body that the backed-out sizing die will straighten out the bulge. I inspect the cases VERY carefully, and don't figure on reloading them more than five or six times. Have not had one separate, but I stick with mild loads after the first loading.

Many years ago I had a primer cup blow out like that, but it turned out to be from a lot of Remington LR primers that had defective cups. Remington recalled those primers and sent me a whole carton to replace them. I pulled down the ammo I had loaded and popped the primers, and have not had any more problems. It's possible that a similar problem may be present here, but that's a long shot.

Look carefully at your bolt face, and you will likely see a small pit where the primer blew out. If there is more than one pit, It would indicate that the problem is with the primers. If there is just one pit, it's likely that the bolt is not supporting the case head right there.

Hope this helps diagnose the problem. I treasure my old Arisaka because Dad brought it back form Japan in '46, and I sporterized it when I was in college, but it's a cranky old sucker to load for. Shoots good, though.

Catoosa

Thank you all for the responses. They were all very helpful and I appreciate all your suggestions.

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So I checked boltface and it has two tiny elongated pits around the firing pin hole. Paul I could email you a pic if you went to post it here. Let me know. The rim fits under the extractor a little loose, but it stays there and won't fall out. Also I haven't had any extraction problems at any point (sticky bolt, stuck cases, failures to extract). As far as headspace goes I don't know of anyone making any gauges.

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You have a couple options to check chamber dimensions without gages. The first, and very rough estimate, is to put a couple layers of masking tape on the back of a factory loaded cartridge and try to close the bolt, if it closes headspace is highly suspect. Another method is to obtain some Cerrosafe (Brownells is a good source) and follow the directions to make a cast of your chamber to measure. There are other ways as well, but these are inexpensive and will give you a fair idea.

Steve, you have had two primers blow out, is that right? That would correspond with the two pits in the bolt face.

Have you used any of those primers in other cartridges or rifles?

I had 3 primers blow out from the side and a couple pierced primers caused by the firing pin. I will try the masking tapetrick. Thank you.