Small case rupture(s)

Art3 · Nov 14, 2016

I was shooting some old .30-06 ammo the other weekend (head stamp F A 38) out of my M1917. While not reloads, I figured this section would be the best section to post in. After the second shot, I noticed a few tendrils of smoke whisping out from the action which didn't seem quite right. I found a small sooty crack in the case and called it quits with that ammo for the day. I had shot some of this ammo a few weeks before and when I went back to check that brass, darn if there weren't two more (for a total of 3 out of about 20) showing the same symptoms.

Do you think the rest of the ammo is safe to shoot, or should I scrap all of it? I think I have about 80 or so rounds left. I'm pretty certain it's corrosive, so my intent had been to use it up fairly quickly (and hopefully never worry about corrosive ammo in my stockpile again). I hate to waste it...but I also hate to risk my eyes or my rifle.

Thanks

4570inMD · Nov 14, 2016

Art3 said:
...but I also hate to risk my eyes or my rifle...

The loss of a few rounds cannot possibly compare.

Safety first. Find better ammo.

4570inMD

BigRick · Nov 14, 2016

I wouldn't risk it. Eye's can't be replaced if you have a catastrophic case failure. The fact that you've had at least 3 rupture I'd cut losses and count my luck stars. The real question is it the ammo or the gun? Maybe a Headspace issue? Hopefully someone with more knowledge then me will chime in.

j_h_smith · Nov 15, 2016

Don't shoot that ammo. However, I would disassemble a round or 3 to see if you can find out why they are doing this. Could you take a picture of the headstamps? Are they all the same or different manufacturers?

Good Luck!

U.S.SFC_RET · Nov 15, 2016

I am willing to bet that those rounds were stored laying down for years and corroded the brass.

StickShaker · Nov 15, 2016

U.S.SFC_RET said:
I am willing to bet that those rounds were stored laying down for years and corroded the brass.

^^^ That was my thought as well.

Uncle Duke · Nov 15, 2016

U.S.SFC_RET said:
I am willing to bet that those rounds were stored laying down for years and corroded the brass.

I'm willing to bet you're right.

Doctor_M · Nov 15, 2016

I would dump it. Err on the side of safety. That's not normal.

Sticky · Nov 15, 2016

Agree with all of the above! Dump it

DanGuy48 · Nov 15, 2016

I realize it's a very small chance, and the thoughts about storage are almost certainly correct, but those are remarkably uniform ruptures. Have you had a look at your chamber in that area? Old ammo might be more prone to failure under marginal chamber conditions....anyway, just another thought.

Magnumite · Nov 15, 2016

look to see if the extractor and ejector marks relative to the ruptures are the same

j8064 · Nov 15, 2016

Clearly there is an ammo and/or rifle issue. With splits in the web area I wouldn't shoot it. Next could be a case-head separation which you do not want to experience.

As was suggested, I'd disassemble some rounds and try to understand why the failures occurred. Like many/most old battle rifles, M1917's likely have generous chambers with a lot of room for the cases to expand. Could be deteriorated ammo - could be an undetected rifle issue - or both.

Pulled bullets are reloadable components and powder makes good fertilizer. If you scrap the rounds, waste not - want not...

.

Jerry M · Nov 15, 2016

Yes since these rounds were manufactured in 1938 i say toss them and buy new(er) ammo.

Oddway Otts · Nov 15, 2016

Uhmmm, those rounds may have been sitting undisturbed for two or three or 25 years before I gave them to you. I may have bought them from Ye Old Hunter in Virginia before the Gun Control Act of 1966. Sorry.

Art3 · Nov 15, 2016

Thanks for all the responses...

Oddway Otts said:
Uhmmm, those rounds may have been sitting undisturbed for two or three or 25 years before I gave them to you. I may have bought them from Ye Old Hunter in Virginia before the Gun Control Act of 1966. Sorry.

...and thanks for the bad ammo, Dad! :rolleyes:

I was really hoping for several replies that were something to the effect of, "Oh, yeah, that's a well known manufacturing defect of that particular ammo. It just gives that little mouse fart out of the side of the case, but you'll be fine. Just don't reload it." But I knew that would be too good to be true.

I'm going to try to take apart some of the ammo tonight and take a closer look at the chamber of my rifle. I don't think it's the rifle though. I've shot a variety of ammo out of it (including modern (21st century, even

) commercial, which is indeed noticeably hotter), without anything like this. Also, what you can't see in the picture is that one of the three has a similar but smaller split about 120 degrees away from the big one. I'll still take a really close look at the other brass that came from that rifle though.

John from MD · Nov 15, 2016

In my experience, these types of cracks usually come from old brittle brass. In the thirties, primers had mercury fulminate in them and that will weaken brass. Chamber headspace failures on a worn chamber are circumferential just above the web of the case.

The OP's brass shows no bulging at all in the area that you would expect to see it if a chamber had excessive headspace.

Pinecone · Nov 16, 2016

To check for excessive headspace, compare a fired case to an unfired one. Look at the base to should difference.

Mercury in brass comes from firing the round, where the metallic mercury from the primer is forced into the brass case.

The other issue with shooting these is, each time that happens, a bit of very high pressure, very hot gases are escaping and eroding the chamber wall. So if your chamber was nice and smooth before, then it can become a bit rough, leading to stuck cases.

10xclean · Nov 16, 2016

I had some DEN 43 do this years ago. When I got the ammo, it had some green color crud on it, I used some steel wool clean it up and when I shot it, the same. I believe the green indicated brass was corroded and weak. Pull the ammo, reuse the bullet. throw away brass and powder. Not worth my head and eyes...

Art3 · Nov 16, 2016

I did a little more ammo investigating last night. I cut open one of the ruptured shells to see if there was any evidence of damage or weak spots inside (other than the hole...which was quite obvious). Unfortunately, even after trying to wipe it out, there was really just too much soot inside to really see anything.

I pulled a couple of bullets. The powder seemed ok as far as I could tell. It was homogenous, evenly colored, loose, not clumpy or dusty. There was some shiny black gunk on the base and cannelure of the bullet. I'm not sure what to make of that, but I don't (in my admittedly inexperience opinion) think I saw anything "weird" about the contents of the case.

I did find something very interesting when I cut that case apart. While it is not in the same location as the failures, this stain on the inside of the case:

Matches up exactly to this stain on the outside:

Which seems to indicate that some degree of corrosion of the case was penetrating it. Whether it came from the inside out or vice versa, I don't know. If some kind of reaction is going through the case wall up there, surely the same thing could be happening at the location of the ruptures. It just hadn't happened to manifest in this shell...yet. Right?

Well...that seemed reasonable to me, until I made another discovery...that I'm going give it's own post...just because this one feels like it's getting a little out of hand...

Art3 · Nov 16, 2016

...As I was examining more of the unfired ammo, I discovered this:

It was tricky to photograph, but easy to see and even feel with a fingernail. That crack certainly fits the size, shape and location of the failures, doesn't it?

I really really wanted to look inside...but haven't been able to yet. Until an Amazon box arrives tomorrow, the only bullet puller I have is the Lyman "hammer" you can see in the background of the other pics. I've always been a little leery about using it. Last night I had already given myself a little bit of the heebie jeebies with handling and cutting the still primed cases I was working with anyway. After pounding on this one for what seemed like a nail biting eternity (so much so I periodically stopped to check whether or not the puller had cracked yet), I couldn't get it to budge and kinda lost my nerve and gave up. While these rounds are "bad," none have them have been duds, and it just didn't seem right to keep subjecting it to shock (after shock after shock) like that.

When the collet style puller arrives, I'll open the shell up and see if it looks like chemical deterioration or a mechanical crack from the inside.

This certainly looks like the smoking gun to my gun smoking

Small case rupture(s)

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