ColoradoNick Posted April 9, 2023 Author Share Posted April 9, 2023 12 hours ago, terrydoc said: Doesn't stop people claiming it does, same as the 320, always the tool not the nut behind the butt. Weird how the 320 has been involved in so many court cases of people shooting themselves too... and sigs reputation for product testing on consumers with its first gen products. Link to comment Share on other sites More sharing options...
terrydoc Posted April 10, 2023 Share Posted April 10, 2023 And you made the point in your comment, " people shooting themselves " Link to comment Share on other sites More sharing options...
erwos Posted April 10, 2023 Share Posted April 10, 2023 The instances I've experienced have not been firing out of battery; it's the case head failing because it's not being properly supported. Glock 40s used to do this quite a bit back in the day for exactly the same reason. I'm not saying I love it when it happens (I've started carrying spare extractors with me, lol), but it what it is. My understanding is that the KKMs are fully supported, so that's the solution if it worries you too much. Link to comment Share on other sites More sharing options...
Racinready300ex Posted April 10, 2023 Share Posted April 10, 2023 So I'm counting like 10 guns in this thread that had something blow out of them. Several guys having it happen more than once. Link to comment Share on other sites More sharing options...
ColoradoNick Posted April 10, 2023 Author Share Posted April 10, 2023 From what I can gather the barrel doesn't support the case enough along with using a 12lb recoil spring and the gun not going fully into battery can cause it to FOB. I can duplicate this in dry fire with my wife's gun and her well worn 12lb spring. Just tossed it and swapped to the heavier spring. We will order the KMM barrel if she decides to keep it. She wants to try a Canik before deciding. Link to comment Share on other sites More sharing options...
HOGRIDER Posted April 10, 2023 Share Posted April 10, 2023 (edited) IMO, there's not any difference to speak of when comparing case support of a Match fit KKM barrel with my stock Sig P320 MAX. Here's a pic showing two of my match loads: 124g JHP @ 1.080" OAL, both in Win fully processed brass. Early on I experienced the slide not fully going into battery during some ransom rest testing. Also showed up when hand cycling the slide. Come to find out it was being caused by me using 1911 length recoil springs which were definitely shorter than the stock Sig springs. After talking with ISMI spring co and TSA, both recommended I switch back to the factory length springs. ISMI sent me some different weight springs to try; and this completely fixed my issue!! It appears the 1911 springs will work fine in the 4.7" Sigs such as the AXG Pro...... At this point I feel these FOBs are being caused directly by case failures along with improper loading practices.....or, an improperly modified pistol that's not functioning as designed. Edited April 10, 2023 by HOGRIDER update Link to comment Share on other sites More sharing options...
Miranda Posted April 10, 2023 Share Posted April 10, 2023 yow. thank you for the photo, Hogrider. The comments on springs is good to know. Both these barrels require the use of new brass. To split a hair, the KKM looks a weee bit more supported and not enough for me to think it will make much difference. The barrels frighten me. I will follow my own conclusions from there. I have been told the many engineers in the gun industry know more than I do. Collectively, they might... To quote a very young lady I met long ago... "that is a whole bag of nope." I am calling that an unsupported 9mm case. case blowout from reloads will be common. miranda Link to comment Share on other sites More sharing options...
fireman1776 Posted April 11, 2023 Share Posted April 11, 2023 2 hours ago, HOGRIDER said: IMO, there's not any difference to speak of when comparing case support of a Match fit KKM barrel with my stock Sig P320 MAX. Here's a pic showing two of my match loads: 124g JHP @ 1.080" OAL, both in Win fully processed brass. Early on I experienced the slide not fully going into battery during some ransom rest testing. Also showed up when hand cycling the slide. Come to find out it was being caused by me using 1911 length recoil springs which were definitely shorter than the stock Sig springs. After talking with ISMI spring co and TSA, both recommended I switch back to the factory length springs. ISMI sent me some different weight springs to try; and this completely fixed my issue!! It appears the 1911 springs will work fine in the 4.7" Sigs such as the AXG Pro...... At this point I feel these FOBs are being caused directly by case failures along with improper loading practices.....or, an improperly modified pistol that's not functioning as designed. There is a difference and it's larger than your photos make it appear because of the angle you took the photo. Even with the angle you used the difference is still obvious. I have the same KKM barrel. When I had my mini kaboom with the p320, the case was blown out in the small space that is not supported on the factory barrel. Also, it's not just the bottom of the case that isn't supported, it's the diameter in the chamber as well (at least in my examples). If I stick a round in the factory barrel there is lateral movement. The round will wiggle. No such thing with the KKM, it has much tighter tolerances. Link to comment Share on other sites More sharing options...
HOGRIDER Posted April 11, 2023 Share Posted April 11, 2023 14 minutes ago, fireman1776 said: There is a difference and it's larger than your photos make it appear because of the angle you took the photo. Even with the angle you used the difference is still obvious. I have the same KKM barrel. When I had my mini kaboom with the p320, the case was blown out in the small space that is not supported on the factory barrel. Also, it's not just the bottom of the case that isn't supported, it's the diameter in the chamber as well (at least in my examples). If I stick a round in the factory barrel there is lateral movement. The round will wiggle. No such thing with the KKM, it has much tighter tolerances. I'm sure your correct on the appearance due to the angle of my photo. It's also hard to actually see the poor chamber dimensions of the stock barrel with it's black finish. I do feel, based on the fit and accuracy of the KKM, it's a superior barrel compared to the stock Sig. And that also relates to "much tighter tolerances" as you pointed out! Link to comment Share on other sites More sharing options...
ColoradoNick Posted April 11, 2023 Author Share Posted April 11, 2023 Here's a couple photos from my wife's P320 X5 Legion vs my CZ S2O. It's alarming to me for sure... I have a KMM barrel on order, swapped in her 14lb recoil spring and won't be shooting reloads through it anymore. Link to comment Share on other sites More sharing options...
dtuns Posted April 11, 2023 Share Posted April 11, 2023 I had one in My P365XL but happened well seating the mag slide went forward and bang. Link to comment Share on other sites More sharing options...
kellymc Posted April 11, 2023 Share Posted April 11, 2023 On 4/10/2023 at 11:40 AM, erwos said: The instances I've experienced have not been firing out of battery; it's the case head failing because it's not being properly supported. Glock 40s used to do this quite a bit back in the day for exactly the same reason. I'm not saying I love it when it happens (I've started carrying spare extractors with me, lol), but it what it is. My understanding is that the KKMs are fully supported, so that's the solution if it worries you too much. I had a 1/2 dozen case head ruptures in just 300 rounds. Zero with the KKM barrel Link to comment Share on other sites More sharing options...
erwos Posted April 11, 2023 Share Posted April 11, 2023 51 minutes ago, kellymc said: I had a 1/2 dozen case head ruptures in just 300 rounds. Zero with the KKM barrel That's a screwed-up barrel, and it should have been sent back to Sig. I have a couple of X5 barrels on order from KKM, so I don't really need to be convinced. Link to comment Share on other sites More sharing options...
Miranda Posted April 11, 2023 Share Posted April 11, 2023 heads up guys. the WshPst news outlet is reporting on the weapon in this thread. I suggest we chose to talk over this in 6 months from now. miranda Link to comment Share on other sites More sharing options...
OPENB Posted April 11, 2023 Share Posted April 11, 2023 I had an early Legion. I used minor PF reloads, around 130PF. I had a case blow out the extractor and a face full of powder. I found the case and the extractor because it was an indoor range. Case was all mangled up, the extractor appeared unharmed. I put it all back together and shot it the next week, and it ran fine for several years. This is before there was any talk of out of battery rounds being fired. I don't remember if it was before or after I had the loaded chamber barrel replaced by SIG. Link to comment Share on other sites More sharing options...
Stuey Posted April 11, 2023 Share Posted April 11, 2023 1 hour ago, Miranda said: heads up guys. the WshPst news outlet is reporting on the weapon in this thread. I suggest we chose to talk over this in 6 months from now. miranda The article focused on it discharging in people’s holster without them touching the trigger. It is free to read online: https://www.washingtonpost.com/dc-md-va/2023/04/11/sig-sauer-p320-fires-on-own/ Link to comment Share on other sites More sharing options...
Miranda Posted April 11, 2023 Share Posted April 11, 2023 siiiiigh. never mind. now our discussion will end up in that follow on report. I have a very hard time seeing anything i consider as good in the results... miranda Link to comment Share on other sites More sharing options...
motosapiens Posted April 11, 2023 Share Posted April 11, 2023 the firing by themselves thing has been a concern for a few years. I've only read about it happening to cops, and from my 16 years experience working in an LE agency, it might not be the gun, lol. regarding out of battery firing.... if ours is the tiniest bazillimeter out of battery it'll just light strike. switching to a 13lb recoil spring has helped as long as we don't use super-hard primers. Link to comment Share on other sites More sharing options...
Miranda Posted April 11, 2023 Share Posted April 11, 2023 24 minutes ago, motosapiens said: snip... lol. regarding out of battery firing.... if ours is the tiniest bazillimeter out of battery it'll just light strike. switching to a 13lb recoil spring has helped as long as we don't use super-hard primers. I agree with the reason for the laughter. It was the first think I thought... and then 'training...' which is not as humorous. I post to ask how a recoil (the big one right?) spring can affect the performance of firing pin. I had not thought them related. (honest question.) miranda Link to comment Share on other sites More sharing options...
HOGRIDER Posted April 11, 2023 Share Posted April 11, 2023 IMO, Edmond has one of the best understandings of how the P320 functions; including it's safety mechanisms! And provides very easy to understand videos of such! https://www.youtube.com/@SIGMECHANICS/videos Excellent resource! Link to comment Share on other sites More sharing options...
ColoradoNick Posted April 11, 2023 Author Share Posted April 11, 2023 1 hour ago, Miranda said: I agree with the reason for the laughter. It was the first think I thought... and then 'training...' which is not as humorous. I post to ask how a recoil (the big one right?) spring can affect the performance of firing pin. I had not thought them related. (honest question.) miranda A heavier recoil spring will make sure the slide fully returns to battery. Link to comment Share on other sites More sharing options...
Jsjac Posted April 12, 2023 Share Posted April 12, 2023 A heavy recoil spring also helps with resisting slide bounce. Link to comment Share on other sites More sharing options...
Sarge Posted April 12, 2023 Share Posted April 12, 2023 1 hour ago, Jsjac said: A heavy recoil spring also helps with resisting slide bounce. Heavy springs also drive the nose down. Best option is to find a weight that does what you need the gun to do reliably then stop there. Link to comment Share on other sites More sharing options...
HOGRIDER Posted April 12, 2023 Share Posted April 12, 2023 26 minutes ago, Sarge said: Heavy springs also drive the nose down. Best option is to find a weight that does what you need the gun to do reliably then stop there. Absolutely!!!!! Link to comment Share on other sites More sharing options...
Miranda Posted April 12, 2023 Share Posted April 12, 2023 lets jump in... yall all seem to know this fixes FOB... are the armorers for police and agencies replacing the old worn sagging main springs with incorrect ones? miranda Link to comment Share on other sites More sharing options...
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