Hey yall! New to the forum from the great state of Georgia! I purchased my first and so far only Sig back in December of 2019, A P320 Carry certified pre-owned. From what I can tell, it has all the GEN II upgrades.

Over the past several years, I have ran primarily steel case ammo through most of my guns for practice at the range, and can only remember a handful of issues out of the several thousand rounds of Tulammo and Wolf 9mm I've shot. During this time, I have ran steel case ammo through various Glocks and M&Ps that I previously owned with little or no issues.

After acquiring the Sig P320, I initially ran steel case through it with some success, with only a round in every couple of magazines failing to extract. I also noticed when new, the gun ejected most empties straight back either over on onto my head (this has went away for the most part) The issue has become progressively worse over time, and I only experience Type 3, failure to extract malfunctions. Either the fired case is partially extracted or it is still completely in the chamber, with the slide coming back behind the following round in the magazine attempting to pick it up but with it having nowhere to go.

Last week, after firing approximately 1,000 rounds through the gun (around 60% of which was steel case), I decided to take down and clean the extractor and it's components. The extractor had a small amount of carbon build-up but the extractor channel and other parts were relatively clean. After cleaning everything, I proceeded back to the range and found the gun now performs worse with steel case, failing to eject every other round. The gun has performed flawlessly with brass case ammo thus far, but I am perplexed as to why it is choking so bad with steel case when I have had such success with it in other platforms.

I do apologize for being so long winded, but was to explain the issue thoroughly. I have posted this on other forums, but most of the responses have been something to the effect of "get rid of it" or "steel case is just bad ammo", etc. I am trying to diagnose the problem so hopefully it can be corrected. I have ordered all new extractor components from Sig in addition to a stainless steel billet extractor from Lone Wolf.

Any insight yall could offer would be greatly appreciated!!

Welcome to the forum.
You refer to both extraction and ejection failures, but they are not the same thing. If the case is not being pulled out of the chamber, or only part way, that’s an extraction problem. If it’s pulled fully out of the chamber, but not being thrown (ejected) out of the gun, that’s an ejection problem.

Ejection failures are usually caused by low slide velocity, and if you’re having problems only with one type of ammunition, it may be low powered.

Extraction failures are usually due to a problem with the extractor or possibly the ammunition. There could be something about how the steel cases hang up when fired and somehow prevent the slide from moving freely (and that could also result in ejection failures). Or the characteristics of the case could contribute to extraction failures. A slight variation in the case rim could made a difference.

Cleaning the extractor was a good first attempt to cure such a problem, but it’s possible that the extractor is damaged in some way, especially if the problem become worse after you cleaned it. Fans of steel cased ammo are adamant that it’s no harder on extractors than brass or aluminum, but steel is steel and other metals aren’t. And it doesn’t necessarily matter that case steel isn’t as hard as extractor steel. I have a chipped tooth filling that wasn’t caused by eating something that was harder than the filling material.

I would inspect your extractor carefully, but the best test will be to replace it and see if that cures the problem.

Welcome aboard. I too think its ammo related. And the 320 has a very easy to replace extractor. I would just order a new extractor and related components and try the gun again.
Since its a CPO gun, who knows what the round count was before it reached you. The extractor may have been borderline during the CPO assessment at Sig and your use of steel case wore it even further.

Thank yall for your input. When I received the gun, it appeared as if it was unfired, with wear apparent on the barrel or other corresponding areas to indicate the gun was even used. It was possibly a gun that had been ordered and returned, but could not be sold as new at that point.

As a CPO gun, you have a 1year warranty from Sig. If you can’t get it working , call SIG and send it back. But I am pretty confident they will not be of much support with using steel cased ammo, but it never hurts to ask.

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Georgian, welcome to SigForum!

When you say you believe your P320 has all the Gen II updates, are you including the P320 Extractor Update or just the Drop Safety upgrades?

We have Extractor issues covered in this thread in the Armorer section of SigForum:
www.SigForum.com/eve/forums/a/tpc/f/150601935/m/7630095024?r=7630095024#7630095024

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Only problem I ever had with my 320 compact was a chipped extractor. It was the same sort of progressively worsening extraction issues you describe.

The gun was pre-upgrade, so I just replaced the old extractor with the new extractor and spring.

No issues since the replacement.

I believe it is the updated parts only because the grip module has a born on date of 10/2018. The extractor is marked "042; 00". At this time I have no other parts to compare to the extractor pin or spring. The nose of the extractor does appear to be peened slightly, but this may be normal.

Both of my P320 carry's developed extraction issues. Both were sent back to Sig and fixed. No problems since. One was purchased new and the other was a CPO.

Sig made a subtle change to the length of the extractor spring, and the geometry of the extractor claw.

More common is the incorrect reassembly, for those who have removed the plunger, spring or claw. Make sure the parts are installed correctly.

Also make sure you greased the rails and properly lubricated the pistol.

If none of the new extractor parts make a difference, I'll have no choice but to send it back to Sig....thankfully I'm still within the one year warranty period allowed with CPO guns. You would think that extractor steel would be hardened and heat treated well enough to withstand steel case ammunition, if in fact it was damaged by my use of that ammo. I still love my Sig so I really hope everything works out.

Well the Lonewolf stainless steel extractor came into today for my P320. I popped it in and headed down to the shooting range. I first ran about 100 rounds of brass through the gun, which was cleaned prior to today's range visit. The gun ran fine with brass, but as soon as I loaded her up with Tulammo, it began to choke bad again. Still having the same exact Type 3 Malfs every other round. New Sig factory extractor parts are on their way to replace what I have in the gun. It that does not work, I will either send it back to Sig or ditch the gun and go back to Glock or Smith & Wesson for a striker fired handgun. I expect a handgun to run anything I put in it, within reason; I do not believe expecting the gun to run with steel case to be unreasonable. I have several thousand of this ammo on hand, and if I were to need to use to defend myself or my family, the gun should handle it. I do not even know if sending it back to Sig at this point would tell me anything, as they are just going to test fire it with brass and tell me not to use steel case ammo.....