P320 .40 cal magazine feeding issues

[earthshine402]

A friend of mine recently bought a Sig P320 in 40 cal to pair with his x5 parts - tungsten grip module, fire control group, etc.. to shoot Limited with. It seems to work alright, other than he has a fair amount of jams.  Further inspection reveals that it seems that the rounds may be getting hung up on the front portion of the mag, not clearing the tube. Either the bullet itself gets stuck, or the rim of the case. This occurs both with aftermarket basepads and springs, and the original factory magazine baseplate and spring. Has anyone seen this issue and resolved it? It seems that the front of the tube needs to be filed down a little in my opinion, but I wanted to ask first if anyone else has figured this one out. 

 

Thanks!

[Manwithnoname]

Is he using factory ( factory length) or long loaded ammo? I had that issue with long loaded ammo for an STI 1.180”. If I use 1.15” or factory ammo I do t have any issues. I’ve only used the 18 round mags with springer base and grams internals. I get 20 reloadable with that setup. 

[JayB059]

Factory length ammo ... the biggest offender is Federal Syntech, 205 gr. I have the 14 round mags with TTI +5 bases and their springs, but stock follower. The issue doesn't have anything to do with how many rounds are loaded though, it can happen with 10, 5, 2, etc. It actually can be seen when unloading the mags by hand. It happens on all 4 mags too. I know grams has followers (and springs) ... not sure if that would help here though. I can try to post some pictures at some point.

[earthshine402]

Factory length ammo ... the biggest offender is Federal Syntech, 205 gr. I have the 14 round mags with TTI +5 bases and their springs, but stock follower. The issue doesn't have anything to do with how many rounds are loaded though, it can happen with 10, 5, 2, etc. It actually can be seen when unloading the mags by hand. It happens on all 4 mags too. I know grams has followers (and springs) ... not sure if that would help here though. I can try to post some pictures at some point.

Maybe it's worth trying the grams springs and followers. I use them in all of my 2011 mags.

Sent from my Pixel using Tapatalk

[Gen]

I ran into this same problem using the same combination of parts.  The solution that has worked for me was to reduce my COAL to 1.100.  The bullet would drag on the front of the mag and give me a failure to feed because the round was coming up too slow.  I had less problems with copper projectiles but if I loaded a powder coated projectile it would happen at least 50% of the time.  I have the Grams followers and running a 16# spring in the gun.

 

Gen

[earthshine402]

We spent a few hours magazine tuning last night. We did several things:

1. Compared 9mm magazines. Sig 320 9mm measured .350, Tanfo 9mm .357, STI Spec per Dawson tuning .350-.355. The 9mm Sig magazines work, and are in range of other magazines and specs.
2. Compared .40 magazines. Glock .40 .377 back, .385 front. Sig .40 .370 front and back, STI Spec per Dawson tuning .380-.385. The Sig .40 mags were significantly tighter than a referenced Glock magazine and the STI tune specs.
3. Tuned the Sig magazines, with .375 back, .383 front. Initial hand feeding out of the mag indicated that there was a little more clearance from the front of the magazine tube and less hang-ups occurred when hand unloading the magazine. I still actually had the bullet nose get stuck, potentially due to the second round getting pushed forward and being pointed down to begin with.
4. Plan is to test out the new tune. If that doesn't work, we may cut away material from the front of a magazine to make it resemble STI or MBX mags.

Edited December 7, 2019 by earthshine402

[Posvar]

On 12/7/2019 at 7:37 AM, earthshine402 said:

We spent a few hours magazine tuning last night. We did several things:

1. Compared 9mm magazines. Sig 320 9mm measured .350, Tanfo 9mm .357, STI Spec per Dawson tuning .350-.355. The 9mm Sig magazines work, and are in range of other magazines and specs.
2. Compared .40 magazines. Glock .40 .377 back, .385 front. Sig .40 .370 front and back, STI Spec per Dawson tuning .380-.385. The Sig .40 mags were significantly tighter than a referenced Glock magazine and the STI tune specs.
3. Tuned the Sig magazines, with .375 back, .383 front. Initial hand feeding out of the mag indicated that there was a little more clearance from the front of the magazine tube and less hang-ups occurred when hand unloading the magazine. I still actually had the bullet nose get stuck, potentially due to the second round getting pushed forward and being pointed down to begin with.
4. Plan is to test out the new tune. If that doesn't work, we may cut away material from the front of a magazine to make it resemble STI or MBX mags.

Any update on how it’s doing?

[earthshine402]

18 minutes ago, Posvar said:

Any update on how it’s doing?

not good. My friend sent the gun back to Sig, they put in a new barrel. He tried a heavier recoil spring with a modified magazine with the front surface trimmed off via dremel to make it look more like an STI mag. nose dives. I recommend he get rid of it at this point, it seems that the Sig P320 does not seem to function well in .40. We have both spent way too much time and effort trying to get the thing to work with all sorts of different ammo.

[thormx538]

That's pretty crazy that it is still having issues. Is the mag seating all the way in the grip? Has he tried it in a different grip frame or different mag catch?

 

I have full size and compact 40 slides and have never had a problem, and I mix/match parts all the time.

[Posvar]

I hope it gets remedied. A heavy tungsten limited .40 would be a nice shooting gun.

[JayB059]

At some point after my post here, I found someone with a similar issue over on SigTalk: https://sigtalk.com/p250-p320-p320-x-5-pistols/365326-p320-40-s-w-failure-feed.html ... I posted findings there (with pictures) and others posted with similar issues too. I just posted there now as well. Here's the bullet points of this fiasco:

 

* I tried grams spring and follower, no change

* I sent gun back to Sig, they swapped the barrel, issues were still there when I got it back

* I cut one of my mags with a Dremel, the front lip that was contacting the cartridge ... FTFs still occurred, this time they were jamming into the feed ramp and getting stuck there

* Tried the heaviest recoil spring I had (18#), issue still occurred

* For some of the rounds that did feed, the gun still cycled weird ... you can feel it, hard to explain beyond that

* Was told by someone at Sig that this is a known issue and a fix is in the works ... I don't think it's high priority because there's less .40 interest these days (outside of USPSA)

 

@Gen , I can see how loading shorter could help, but I'm not in a position to do that since I don't reload.

 

@thormx538 , mags are seated all the way. I have used two different factory mag catches (the original and one from Springer Precision with the paddle). I have mostly used the TXG grip module. I have shot it in its original full size configuration, but not enough to determine anything. Note that I'm using the FCU from a 9mm P320 that has the GrayGuns competition trigger kit.

 

At this point in time, I'm done troubleshooting this issue and am moving onto a new platform for Limited Major. When Sig release their "fix" in the assumed form of an official X5 in .40, or similar, that will be cool, but since I've already moved on, it likely won't be something for me, but we'll see.

[OPENB]

18 hours ago, JayB059 said:

At some point after my post here, I found someone with a similar issue over on SigTalk: https://sigtalk.com/p250-p320-p320-x-5-pistols/365326-p320-40-s-w-failure-feed.html ... I posted findings there (with pictures) and others posted with similar issues too. I just posted there now as well. Here's the bullet points of this fiasco:

 

* I tried grams spring and follower, no change

* I sent gun back to Sig, they swapped the barrel, issues were still there when I got it back

* I cut one of my mags with a Dremel, the front lip that was contacting the cartridge ... FTFs still occurred, this time they were jamming into the feed ramp and getting stuck there

* Tried the heaviest recoil spring I had (18#), issue still occurred

* For some of the rounds that did feed, the gun still cycled weird ... you can feel it, hard to explain beyond that

* Was told by someone at Sig that this is a known issue and a fix is in the works ... I don't think it's high priority because there's less .40 interest these days (outside of USPSA)

 

@Gen , I can see how loading shorter could help, but I'm not in a position to do that since I don't reload.

 

@thormx538 , mags are seated all the way. I have used two different factory mag catches (the original and one from Springer Precision with the paddle). I have mostly used the TXG grip module. I have shot it in its original full size configuration, but not enough to determine anything. Note that I'm using the FCU from a 9mm P320 that has the GrayGuns competition trigger kit.

 

At this point in time, I'm done troubleshooting this issue and am moving onto a new platform for Limited Major. When Sig release their "fix" in the assumed form of an official X5 in .40, or similar, that will be cool, but since I've already moved on, it likely won't be something for me, but we'll see.

Glad I didn’t jump on a cheap 40 P320 for a poors Limited gun. Was tempted. 

[hardluk1]

 Wonder why they need  to fix what use to work so darn reliably as in my full and compact 5 year old 40sw but I also primarily run  home rolled Missouri 155gr coated swc with  some zero 165gr  hp  . While carry ammo is 155gr gold dot from underwood  or Georgia arms same load  .  Never had a feed or function issue even but I have  very limited 180gr  trigger time  over the years even when I shoot 40sw in uspsa  .  I had to try some georgia arms  canned heat and some 180gr hst after reading about others issues .   I have not shoot matches in some years and only fire a couple thousand rounds fired a years  now  but not a  standard or light load guy ether .  

 

  All you guys that think they have mag issues do they run fine with stock lengths ?  Even my 8 old mags bought when new  run reliably and  are tighter than any  I see measured here   with a .368 front and rear  . They seem reliable in my new p320XC 9mm  just to see if they run well there too just in case like guys have done with conversion barrels in 40's  !  Only run around 1000 rounds thru it but all the mags run so far .  

 

 I'm think sigs has produced to many variations  over its short life span and QC is lacking 

[DS451]

I'm a firearms instructor for a small PD in Connecticut, about 50 sworn personnel.  During a recent range sessions with a small group, we were experiencing the same failure to feed issues with our P320, .40, Full Size.  The casing and or nose of the bullet, (180 gr, Speer ball and Gold Dots), were getting hung up on the front of the mags.  Was advised by Sig that the mags need to be replaced at our own expense.  Our guns and mags are approximately 2.5 years old.  I anticipate that we will see more problems when I run the agency through its annual qualification at the end of April, early May. 

 

The typical service life of our duty weapons is approximately 10 years.  I will be looking to go back to Glock, probably sooner, as we don't have confidence in the P320's reliability.  We've already done the gun exchange with the drop issue in 2017.  Then we did a 1 for 1 magazine exchange with the original magazines that came with the previous guns for the current magazines.  And still continuing to have problems.  Totally frustrating.

[DirectDrive]

2 hours ago, DS451 said:

I'm a firearms instructor for a small PD in Connecticut, about 50 sworn personnel.  During a recent range sessions with a small group, we were experiencing the same failure to feed issues with our P320, .40, Full Size.  The casing and or nose of the bullet, (180 gr, Speer ball and Gold Dots), were getting hung up on the front of the mags.  Was advised by Sig that the mags need to be replaced at our own expense.  Our guns and mags are approximately 2.5 years old.  I anticipate that we will see more problems when I run the agency through its annual qualification at the end of April, early May. 

 

The typical service life of our duty weapons is approximately 10 years.  I will be looking to go back to Glock, probably sooner, as we don't have confidence in the P320's reliability.  We've already done the gun exchange with the drop issue in 2017.  Then we did a 1 for 1 magazine exchange with the original magazines that came with the previous guns for the current magazines.  And still continuing to have problems.  Totally frustrating.

That alone would be enough for me to start looking for another brand.

 

[OPENB]

I went ahead and got the Sig P320 40 Red Box full size from CDNN. It came with 3 14rd. mags, and I bought 4 18rd. mags. I dropped the top end on my Legion bottom, and ran a couple mags of 200gr. round nose Berry’s Bullets reloads. No hiccups. Maybe I got lucky with a good one. 

[DS451]

I spoke with another Sig rep on 03/20/2020.  Was told they would be now sending me 30 mags at their expense and I would return the problem mags for them to evaluate.  I will be conducting some more tests next week on the range to get some verifiable and repeatable data regarding the problems mags.  My sister agency in the next town over have not reported any mags issues with their P320 (40, Full), however, they've cited that they have had some barrel/chamber tolerance issues that which they had to send guns back to Sig to be fixed and or replaced.

[thormx538]

On 3/21/2020 at 11:10 AM, DS451 said:

I spoke with another Sig rep on 03/20/2020.  Was told they would be now sending me 30 mags at their expense and I would return the problem mags for them to evaluate.  I will be conducting some more tests next week on the range to get some verifiable and repeatable data regarding the problems mags.  My sister agency in the next town over have not reported any mags issues with their P320 (40, Full), however, they've cited that they have had some barrel/chamber tolerance issues that which they had to send guns back to Sig to be fixed and or replaced.

 

That's a much better response from Sig than their first one