The first day I used what was described as a "match .357 SIG barrel" in my Sig P229, I got a bullet lodged in it. All the signs (quiet discharge, especially since the load was previously producing big loud muzzle flashes) point to it being a squib load. But something strange happened to the case which leads me to wonder if it wasn't something else.

When I extracted the spent case, I noticed the mouth was damaged. It would appear that gases cut two notches in the mouth, and from what I and uncruel saw, it almost looks like the brass melted a little in the process.

Once uncruel has a little time, he's going to take some pictures of the case for me so we can post them here for those of you more experienced than we are to analyze.

Now, I'm not ruling out the possibility of the case being damaged in the process of handloading and we just didn't notice it, but previous experience says such things wouldn't cut two narrow grooves in the case, especially not so close to each other.

We dislodged the bullet, and there doesn't seem to be any damage (I was told that I'd feel a bulge when cleaning the barrel with a tight patch and I didn't feel anything abnormal).

Could the chamber be improperly cut? As it is possible the case was a reused one from another gun, could the chamber of a previous gun have been improperly cut?

Needless to say, I'm probably going to pull all of the bullets in the remainder of that batch of ammo, just to be sure, and I may decide to take the barrel to a gunsmith to see if there's any reason to not use it again.

You wouldn't get a bulge in the barrel unless you fired another cartridge with this bullet still lodged in the bore.

Several things could have happened - the match barrel MAY have a tight (minimum) chamber dimension. The case could be too long and didn't chamber properly. The cartridge could have been assembled in a defective manner (squib load). The case may have been defective and was missed during case inspection prior to loading.

Ok, so we have the pictures now. After seeing it all blown up like this, I really have trouble believing that was caused by the loading equipment.

http://www.coreth.com/tmp/x5198-600x600.jpg (http://www.coreth.com/tmp/x5198-2900x2900.jpg)
(click the image if you want to see a larger, more detailed version)

Certainly has that eroded by gas look about it...and if I had to guess, would be that the case neck was cracked, some of the burning gas took the easier way out by eroding the crack and jetting back.

Case necks crack....they can crack while ammo is in storage, can crack while seating the bullet, and can crack from the stress of being fed into the chamber, so you can't catch them all just from a good inspection at the loading bench.

.357 Sig doesn't have much of a shoulder to headspace on.

My thought is, could have gotten inconsistent / poor ignition of one of the rounds if the shoulder had been pushed too far back and the round slipped forward in the chamber.

Primer well dented? Do the case heads sit flush with the back of the barrel extension, when you drop each of the remaining loads into the barrel (with it removed from the gun)?

By the look of the split and carbon stains, would hazard the quess you didn't get a good chamber seal, as suggested by MikeG. As ribbonstone pointed out, sometimes the smallest neck crack can fatigue quite rapidly and end up with what you show, especially if the cartridge was loaded on the warm side.

Think what the case is trying to tell us is:
1. The erosion / brass depostion is outwards.
2. To erode / deposit outwards the case had to crack early (or before) the powder burn, or at least before the powder burn got up to full pressure.
3. COULD be that a little lip of case got folded inwards or outwards by being carught on the bullet base, and that fold became the roughtly triangle (at least two sides of one) crack when it unfolded, and the gas pressure just eroded it as the pressure rose.

I have little experience with auto loaders, so feel free to call me stupid. I see marks near the case web that indicate a feeding problem that accelerated wear on one side of the case. Gas took the path of least resistance.

Good image by KO Improbable.

How many reloads?
Cheezywan

Being a gun nut for as long as I can remember there was a question about some loads in the old ammo catalogs. There were 38/44 high pressure loads that were developed for a 38 spec some time before the 357 mag came out. They were listed at 1100 fps with a 158 gr bullet from a special S&W 44 size frame revolver in 38 spec. The odd thing about them was that they were shown as having a "Metal Point". The bullet was indeed made with a metal point only having a jacket on just the tip with the shank being lead. Never could find an explanation except that the metal point would penetrate a car body better. Some years ago found out that the powders at that time would not workwith a jacketed bullet at those pressures. When fired the bullet would lodge in the forcing cone, then the powder would burn producing a blown up gun. The bullet acted like a bore obstruction. So they just put a jacket on the tip. Looking at the case and bullet it looks like thats what happened here. The base of the bullet is burned and the case was partially melted. It could be that the primer was weak and popped the bullet forward and then the powder burnt. What powder was it?

Iron, I think someone fed you a line of BS. Back in the day, they were driving jacketed bullets with blackpowder and when they went to cordite, things heated up and guns failed from weakness of the design and components, not from the powder. If the bullet indeed lodges in the cone and the gun let loose, something went wrong somewhere and it was not that the powder lacked the ability to push the bullets. Bad powder maybe, bad gun, whatever?

Reason they metal tip came to light was because of the new laminated glass being used in cars. Sloping angle and higher strength made the standard low power RN bullets of the day slide off rather than penetrate. Jacketed bullets were extremely expensive to mfg and someone got the brainstrom of simply casting a lead slug behind a pointed metal cap and boosting the velocity a little. I read a few indepth articles on these and other police rounds spanning the wheel gun years. These metal tip bullets went through a number of changes as time went by but never really got any major play with LEO's beyond some limited use in big cities. Same deal was done earlier with the .45acp for a tommy gun load but failed because the caps would get knocked off the bullets in the magazine and in the action causing jams.

Another one followed suit, this one was a metal point smaller than bullet diameter, kinda looked like a field point from an arrow set into a roundnose bullet. This one faired a little better but the failure to lock the point into the lead also lead to it's demise for lack of durability as the points would often slide out and jam the cylinders.

The capping and pointing ideas soon faded away in favor of using a hard cast pointed lead bullet but these soon went away when police found they would not do enough tissue damage on human targets to stop them even with multiple hits.

A fellow by the name of Donaldson came out with a compromised shape, hard tapered sides with a small flat meplat on the front and to get increased velocity he cut the weight by using a concave base similar to what you know as a mini ball for a muzzleloader. It worked to some extent but lacked the weight to get good penetration on car bodies. I've seen it written that this is the bullet that spurred Keith to come up with what we are all still familiar with today.

There have been quite a few interesting bullet designs that are long since forgotten or unknown by most. Riot loads for the .38 spcl using four small pointed lead slugs. The "Johnny" bullet designed by a NYC cop that looked like an hour glass. Another one called "the .38 A bomb" had a steel ball cast into the nose and extremely deep lube grooves. There's a host of others too, most of which were known to few beyond the inventor.

There was a book, well more like a magazine, printed in the early 1970's called G-Man ammo or something similar to that. Soft cover, maybe 150 pages of magazine size. Has drawings and descriptions of all kinds of odd bullets either tested or presented to government agencies. A friend of mine had a copy many years back and when I asked him about it about three years ago, he did not know what had become of it. I've been unable to locate a copy since but it is something to keep an eye out for.

Haven't seen or shot all of those, but was give a couple of boxes of the Winchester pointed metal capped loads (some how "Higyway Patrol" is in momory banks on that one). One box held 44 rounds, so we shot those and kept the full box intact.

Litte pointed cap was thick...much thicker than normal jackete materal, and was well swaged into the soft lead bullet...don't see them working loose.

IF they increased pepetration drqastically, couldn't detect it. Did seem to get a clearner hole in steel (old car doors) than when using soft swaged bulletws (which tend to spread out a bit on contact before penetrating) but hard cast certainly did at least as good a job.

HAve also taken apart a .35SW auto round. That one also had a metal capped RN with a lead bullet body. this one is reported to be from fears of early barrel wear with jacketed bullets. Doubt that had any basis in real life, and the whoile .35auto idea died out.
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Think your squib is basic: gas will take the easiest way out.

MikeG: Primer is well dented, and all of the remaining rounds from that batch are flush with the barrel extension.

Cheezywan: This was brand new brass. Credit for the photo goes to Uncruel. It's nice to have a photographer in the family at times like these.

ironhead7544: It was Blue Dot

I was looking at rub marks near the base of the case. My speculation was that the case neck got scratched on the trip up the feed ramp and created a weakness that the powder gases exploited.

Perhaps just a piece of bad brass? I have had loaded rifle brass split necks in storage. It had been reloaded several times though.

It is good that nothing worse than what happened happened.
Cheezywan

I was looking at rub marks near the base of the case. My speculation was that the case neck got scratched on the trip up the feed ramp and created a weakness that the powder gases exploited.

Perhaps just a piece of bad brass? I have had loaded rifle brass split necks in storage. It had been reloaded several times though.

It is good that nothing worse than what happened happened.
Cheezywan

Yeah, I'm thinking it was just a bad piece of brass.

markkw: I think the article was in Handloader magazine. Ill see if I can find it.

markkw: Havent tracked down my copies yet but the artice on the 38/44 should be in Handloader #229 or 230. Anyone have those? From 2004.