**Final Update**

Thanks to Dansedgli, who reminded me that I left this thread without a final answer---

Sig replaced the entire 9mm slide assembly, including the barrel and recoil spring. They believed that there was a very slight barrel fit issue that kept the slide from completely closing but was close enough to allow the gun to fire. They didn't think that the recoil spring had anything to do with it.

All I know is that when I got the new slide assembly, I fired a lot of rounds through it with no problem. Since the original issue cropped up within the first few rounds (round three the first time and round 12 the second time), I know that my problem is now solved.

Dansedgli, is your problem cropping up within the first few rounds? E-mail me (my address is in my profile).



***4th UPDATE***

I've gotten a few questions over the weekend as to whether I'd had ever had any problems at all with my P320 using the original .40 slide.

The answer is no. In fact, I put it back on after both of the KABOOMs I had with the new 9mm slide assembly and ran a full box of ammo through it each time. Ran like a champ.

Nobody's ever done any work on any part of the firing unit (everything is stock), and the only time anyone's touched either of the slides is when Robert Burke replaced the extractor on the 9mm slide after the first incident and checked it to mske sure there was no other damage. So, I pretty much narrowed everything down to the 9mm slide. For that reason, plus the fact that I carry the .40 on duty, is why Sig didn't require me to send in the firing unit as well as the slide.


Full Story:

On Saturday, I had a KABOOM with my P320 from a round that apparently fired out of battery on my third shot ever with a brand new 9mm Caliber X-Change Kit. It cracked the grip frame and blew off the extractor.

Robert Burke replaced the extractor and carefully inspected the pistol. Everything checked out with regard to specs and such, and it appeared to be good to go.

But today, I went back to the range and, on Round 12, the same thing happened (extractor #2 was blown away, but the spare grip frame I was using wasn't damaged). This appears to be something that the factory is going to have to spend some time and effort on, and thank goodness the kit is new and in warranty.

I'm calling Sig tomorrow morning (Monday) for an RMA.

This is the first time I've had to send something back to Sig in more than 20 years. It'll be interesting to find out what caused this problem.

This message has been edited. Last edited by: snoris,

I do..It's a gen 2 black medium grip module. It has some light stippling on the back and where you put your thumb in the frame as well as a spot on the bottom of the trigger guard. I can send you pics if you want. $25+ $5 shipping through pay pal

Shoot me an email at pgfins2@gmail.com if you're interested.

I can send with it the new slide release for if you want.

Pics or it didn't happen.

Bump for update.

You didn't identify the load. Were they the same for both incidents?

Interesting to see what type of ammo was used.

The first was Aguila 115 grain FMJ, the second was Winchester White Box FMJ.

While neither is a top-notch brand, I'd find it hard to believe that the same exact catastrophic failure on consecutive days is due to two different brands of factory ammo.

quote:

Originally posted by Draggun:
I can send with it the new slide release for if you want.

Thanks for the offer! Let's wait and See if Sig is going to fix the slide, barrel, and components under warranty (which they should) before I put you to the trouble.

Since I'm clueless, can OP or other experts explain why this was out of battery firing? What's the evidence? Thanks.

I too am curious as to the cause and outcome. Two kabooms in such a relatively short time period with loads from two different ammo manufacturers. Does appear on the extreme side of long odds if both incidents were due to the ammunition.

But I'm with 12131 here; OOB detonation, what exactly happened as to make you suspect that? The rounds in question went off on their own as the gun was in its cycling sequence during the extraction of the spent case and the chambering of the next cartridge, after the previous cartridge went 'bang'?

It appears that the new rounds coming up from the magazine aren't seating correctly. I took photos of the two spent cases but don't have Photobucket to post them. I'm trying to get that done, and you'll be able to see what's up.

The .40 configuration is working flawlessly, so I know it's nothing in the firing unit.

If you need me to post photos for you my email is in profile.

Here is snoris pic of the bulged brass.

Well, that does look like there were detonations with the rounds not being fully seated. Not good.

And it's gotta be that slide assembly, because with the .40/.357 Sig slide and both barrels, I have over 2,000 rounds fired without any failures.

So, did you contact SIG with info and pics? And what did they say?

Gave the Sig rep a full description of both incidents, pics of both cases from different angles, the slide with the extractor gone, the damaged extractor, the damaged grip frame, and exactly what ammo was used on both occasions. They're sending an RMA.

In the box, I'm sending the slide assembly, the magazine, the broken grip frame, and a paper bag containing the two damaged cases and the second damaged extractor (Robert Burke kept the first one when he changed it out).

They wanted the firing unit, too, but I told them that if the firing unit was part of the problem my .40 slide assembly wouldn't have 2,000 problem-free rounds through it, and that the failure should replicate with any firing unit they have on the bench. Plus, in the .40 this is my duty backup gun. They said okay.

^^^^ Great to hear.

My question is when is it occurring? Are you pulling the trigger and getting a kaboom or firing a shot, then a kaboom as the slide returns to battery?

The first requires that the slide is out of battery when you pull the trigger, and by those cases rather significantly so. In which case I'm curious how the trigger is releasing the firing pin block.

The second could be from a broken or sticking firing pin. Instead of retracting, it stays protruded, striking the primer as its feeding. However, assuming the P320 is controlled feed as I'm sure it is, I'd think a protruding firing pin would cause a jam more likely than OOB kaboom.

I wonder if the most likely culprit is premature unlocking. The case starts to be extracted before pressure has subsided.

I also wonder if ammo could be part of the problem. I know you said it was 2 different manufacturers, which obviously lessens the likelihood. Any chance they were chambered several times before, causing setback?

Anyway, just thinking aloud. Good reminder to always were eyes and ears. Glad no one was hurt.