Sig P320 Carry and Steel Case Ammo

Georgian · May 12, 2020, 01:21 PM

Hey yall. I have owned my factory certified pre-owned (red box) Sig P320 Carry model since fall of 2019. The pistol has a born on date of October 2018, based on the markings present on the grip module. It has all the factory upgrades from what I can tell.

When I purchased the handgun, it appeared as if it was unfired, with no wear present on the barrel or corresponding areas. I really enjoy this gun much more so than previous Glocks/M&Ps that I owned. My one concern is steel case ammo. I understand Sig does not recommend steel case, as do most manufacturers. I ran tons of the Tula and Wolf steel through my various Glock 19s and M&Ps over the years and malfunctions were almost non-existant, but would have from time to time.

Since purchasing my 320, I have put in the neighborhood of 4-600 rounds through the gun, with approximately 60-70% steel case and the rest brass. Every time I go to the range I notice a handful of malfunctions with steel case ammo, all of which of some form of failure to eject. Most often, the handgun will fire, and the slide will lock back with half of the spent case hanging out of the chamber. This is always easily remedied by removing the magazine, working the slide and returning the magazine to continue firing.

My 320 has never experienced a failure with brass case ammo of any type. I am just wondering is it the ammo, the gun, me, or a combination of all three. Any input would be greatly appreciated!

L-2 · May 12, 2020, 03:20 PM

I see you've posted in a few of the other forums I visit. I'll respond here as I tend to like this forum more than those others.

My thoughts in no particular order as I think about this issue:

-I don't understand the slide locking back if there are still rounds in the magazine. I'm thinking that problem could be the shooter bumping the slide-stop.

-I've shot tens of thousands of rounds of steel-cased ammo through various guns, but I don't have a SIG P320. I can understand some extractors not working well with a certain brand of ammo, probably due to a particular ammo's extractor groove shape/size, however.

-I've also had a problem with my SIG P226R's long-external extractor (different from a P320's extractor). On that P226R, there was intermittent extraction and cured with new extractor springs. This was an early problem with some SIG's as that extractor design was relatively new. Luckily, I guessed right about the problem being the springs and is cured my problem. If it didn't cure my problem, I was next going to send the gun back to SIG as it would have required more diagnosis repair with more expensive parts (extractor &/or slide), and with an undetermined down-time.

-Other than obtaining a 2nd P320 to compare, it's a good idea you posted on these forums in hopes of finding someone else who shoots steel-cased ammo through their P320. I hope someone with that specific knowledge answers back soon. So far, I haven't seen anybody respond with this exact combination of P320 and steel-cased ammo. Maybe give it a few more days.

-I'm unaware of any firearm brands specifically recommending against steel-cased ammo, but again, I don't own a P320 and don't have an owners manual from SIG specifically stating not to use this type of ammo. I'll go look at SIG's website after I post this.

-The steel-cased malfunctions I've had with my Glocks tend to be the ammo stack in the mags getting bound up and the mags unable to push the round-stack up to allow consistent feeding. This would be a different problem from what you're having with the P320.

Georgian · May 12, 2020, 03:33 PM

I too remember using Magpul Glock mags and steel case ammo binding in the magazine. Over the years I have probably shot, between .223/9mm, a one or two dozen cases of the stuff. It has never caused any issues in any AR platform I've ran it through. The Tulammo/Wolf 9mm likewise has been good quality. Many believe it is dirtier than brass case, but I have not seen that it is dirtier than any other type of ammunition. I would also not have kept purchasing it if it had not worked reliably. My Springfield 1911 loves steel case and gobbles it up along with my Ruger P85. The extractor claw on the P320 is also quite a substantial piece of steel, much bigger in width than the claw on the P85. Perhaps, as you mentioned, the extractor groove in certain steel case ammo is not compatible with the P320.

dyl · May 15, 2020, 12:03 AM

I have a P320. I've shot steel cased ammo a long time ago for pistol, haven't for years now because I reload.

So this isn't specific to the P320, but here are some things about steel cased ammo in general.

You mentioned steel cased ammo tends to be dirty. They can be. Steel cased ammo tends not to expand / seal the case mouth to the chamber as easily as brass does. Gasses blow back into the chamber with soot leaving you a dirtier gun as less has gone out the barrel. Interestingly, in an AR15, using steel cased ammo may be gentler on gas port erosion because less of the hot gasses are focused forwards. https://www.luckygunner.com/labs/bra...el-cased-ammo/

The rough matte finish on the steel cases and being steel not brass give the cases less lubricity so feeding and extracting is a little dicier. And I'm sure the cheap nature of the steel practice ammo doesn't bode well for a healthy powder charge. If they had +p steel cased ammo or at least a nice full power load I think some extraction issues would be cured.

I think your stovepipes are a combo of steel ammo causing a reduced gas seal at the case mouth upon firing, increased friction upon extraction, possible light charges. It doesn't sound like you're having failures to feed. If you really wanted to tune your pistol to shoot steel cased ammo you could find a reduced power recoil spring and see if that helps, but go too light and the slide might batter the frame and see problems feeding.

May 12, 2020, 01:21 PM	#1
Georgian Senior Member Join Date: October 12, 2004 Location: SE Georgia Posts: 208	Sig P320 Carry and Steel Case Ammo Hey yall. I have owned my factory certified pre-owned (red box) Sig P320 Carry model since fall of 2019. The pistol has a born on date of October 2018, based on the markings present on the grip module. It has all the factory upgrades from what I can tell. When I purchased the handgun, it appeared as if it was unfired, with no wear present on the barrel or corresponding areas. I really enjoy this gun much more so than previous Glocks/M&Ps that I owned. My one concern is steel case ammo. I understand Sig does not recommend steel case, as do most manufacturers. I ran tons of the Tula and Wolf steel through my various Glock 19s and M&Ps over the years and malfunctions were almost non-existant, but would have from time to time. Since purchasing my 320, I have put in the neighborhood of 4-600 rounds through the gun, with approximately 60-70% steel case and the rest brass. Every time I go to the range I notice a handful of malfunctions with steel case ammo, all of which of some form of failure to eject. Most often, the handgun will fire, and the slide will lock back with half of the spent case hanging out of the chamber. This is always easily remedied by removing the magazine, working the slide and returning the magazine to continue firing. My 320 has never experienced a failure with brass case ammo of any type. I am just wondering is it the ammo, the gun, me, or a combination of all three. Any input would be greatly appreciated! __________________ ~"Speak softly and carry a big stick"~T. Roosevelt God Bless

May 12, 2020, 03:20 PM	#2
L-2 Senior Member Join Date: September 8, 2004 Location: Nevada Posts: 522	I see you've posted in a few of the other forums I visit. I'll respond here as I tend to like this forum more than those others. My thoughts in no particular order as I think about this issue: -I don't understand the slide locking back if there are still rounds in the magazine. I'm thinking that problem could be the shooter bumping the slide-stop. -I've shot tens of thousands of rounds of steel-cased ammo through various guns, but I don't have a SIG P320. I can understand some extractors not working well with a certain brand of ammo, probably due to a particular ammo's extractor groove shape/size, however. -I've also had a problem with my SIG P226R's long-external extractor (different from a P320's extractor). On that P226R, there was intermittent extraction and cured with new extractor springs. This was an early problem with some SIG's as that extractor design was relatively new. Luckily, I guessed right about the problem being the springs and is cured my problem. If it didn't cure my problem, I was next going to send the gun back to SIG as it would have required more diagnosis repair with more expensive parts (extractor &/or slide), and with an undetermined down-time. -Other than obtaining a 2nd P320 to compare, it's a good idea you posted on these forums in hopes of finding someone else who shoots steel-cased ammo through their P320. I hope someone with that specific knowledge answers back soon. So far, I haven't seen anybody respond with this exact combination of P320 and steel-cased ammo. Maybe give it a few more days. -I'm unaware of any firearm brands specifically recommending against steel-cased ammo, but again, I don't own a P320 and don't have an owners manual from SIG specifically stating not to use this type of ammo. I'll go look at SIG's website after I post this. -The steel-cased malfunctions I've had with my Glocks tend to be the ammo stack in the mags getting bound up and the mags unable to push the round-stack up to allow consistent feeding. This would be a different problem from what you're having with the P320. __________________ (former) Glock Armorer 1911 Armorer LEO (retired)

May 12, 2020, 03:33 PM	#3
Georgian Senior Member Join Date: October 12, 2004 Location: SE Georgia Posts: 208	I too remember using Magpul Glock mags and steel case ammo binding in the magazine. Over the years I have probably shot, between .223/9mm, a one or two dozen cases of the stuff. It has never caused any issues in any AR platform I've ran it through. The Tulammo/Wolf 9mm likewise has been good quality. Many believe it is dirtier than brass case, but I have not seen that it is dirtier than any other type of ammunition. I would also not have kept purchasing it if it had not worked reliably. My Springfield 1911 loves steel case and gobbles it up along with my Ruger P85. The extractor claw on the P320 is also quite a substantial piece of steel, much bigger in width than the claw on the P85. Perhaps, as you mentioned, the extractor groove in certain steel case ammo is not compatible with the P320. __________________ ~"Speak softly and carry a big stick"~T. Roosevelt God Bless

May 15, 2020, 12:03 AM	#4
dyl Senior Member Join Date: October 31, 2009 Location: Ohio Posts: 1,310	I have a P320. I've shot steel cased ammo a long time ago for pistol, haven't for years now because I reload. So this isn't specific to the P320, but here are some things about steel cased ammo in general. You mentioned steel cased ammo tends to be dirty. They can be. Steel cased ammo tends not to expand / seal the case mouth to the chamber as easily as brass does. Gasses blow back into the chamber with soot leaving you a dirtier gun as less has gone out the barrel. Interestingly, in an AR15, using steel cased ammo may be gentler on gas port erosion because less of the hot gasses are focused forwards. https://www.luckygunner.com/labs/bra...el-cased-ammo/ The rough matte finish on the steel cases and being steel not brass give the cases less lubricity so feeding and extracting is a little dicier. And I'm sure the cheap nature of the steel practice ammo doesn't bode well for a healthy powder charge. If they had +p steel cased ammo or at least a nice full power load I think some extraction issues would be cured. I think your stovepipes are a combo of steel ammo causing a reduced gas seal at the case mouth upon firing, increased friction upon extraction, possible light charges. It doesn't sound like you're having failures to feed. If you really wanted to tune your pistol to shoot steel cased ammo you could find a reduced power recoil spring and see if that helps, but go too light and the slide might batter the frame and see problems feeding.