Rich406 Posted September 12, 2020 Share Posted September 12, 2020 I have 2 identically setup Sig P320 legions. I’ve been having issues with my practice gun. It won’t shoot a consistent group at 15 yards anymore, even from a rest. It used to be ok up until about 10-15k rounds ago. And since then it’s progressively gotten worse. It’s so bad now that it’s hard to even zero the dot. The gun itself has about 78k live rounds and atleast 100k dryfire presses. I though it might be the barrel, I switched that out, but it didn’t make any difference. It’s like it won’t lock up consistently anymore. ive attached a couple pics of the grouping of my match gun (which shoots great) and the practice gun. Anyone have any insight into what’s going on? I’d like to think it’s not worn out, but I guess it might be. Link to comment Share on other sites More sharing options...
BoyGlock Posted September 12, 2020 Share Posted September 12, 2020 Id check the reddot first. Remove the reddot and benchshoot the gun w/ iron sights and see if it groups. Also try it w/ different loads. Link to comment Share on other sites More sharing options...
Rich406 Posted September 12, 2020 Author Share Posted September 12, 2020 7 minutes ago, BoyGlock said: Id check the reddot first. Remove the reddot and benchshoot the gun w/ iron sights and see if it groups. Also try it w/ different loads. I’ve changed out the dot, and also tried 3 different hand loads, and some factory ammo. Some were better than other, but all still sucked. Link to comment Share on other sites More sharing options...
Boomstick303 Posted September 12, 2020 Share Posted September 12, 2020 Maybe try changing out the FCU from the accurate gun. I wonder how the rail tabs on the FCU wear over time. Also how much movement are you getting at the rear of the slide when you pull the trigger. With all of my Sig P320s the slide moves up ever so slightly when I pull the trigger. Perform this test with both FCUs and with the magazine in place in the practice grip module. With snap caps gives the most accurate data for this test but are not required. I wonder with that many rounds throug it if the FCU and slide tolerances are shot? If you can’t figure it out from there strip down the accurate gun and swap one part out at a time and test each component in the practice gun. Link to comment Share on other sites More sharing options...
ltdmstr Posted September 12, 2020 Share Posted September 12, 2020 If you've eliminated the shooter, dot/sights and ammo as the source of your problem, that leaves two possibilities. Either the barrel crown or something to do with the lockup. Link to comment Share on other sites More sharing options...
Rich406 Posted September 12, 2020 Author Share Posted September 12, 2020 17 minutes ago, ltdmstr said: If you've eliminated the shooter, dot/sights and ammo as the source of your problem, that leaves two possibilities. Either the barrel crown or something to do with the lockup. ‘I’ve tried 3 different barrels. It has to be something in the lockup, but what, and is it something that can be fixed? Link to comment Share on other sites More sharing options...
ltdmstr Posted September 12, 2020 Share Posted September 12, 2020 Well, then something has to be loose, broken or worn. If it's the rails or something in the FCU, you can't do anything about it bc that's the serial numbered part. So it can't be replaced, unless they're going to give you a new one under warranty, which I doubt. Could also be something in the barrel block. Other than that, I dunno. Link to comment Share on other sites More sharing options...
zombywoof Posted September 12, 2020 Share Posted September 12, 2020 It's treated you well. You got your moneys worth out of it. Dry fire/back up gun. They're only $900 Link to comment Share on other sites More sharing options...
jwhittin Posted September 16, 2020 Share Posted September 16, 2020 Any update on your issue? Did you solve the mystery? I'm having accuracy issues with my P320 X-Series (GGP slide, Victory barrel, X-series grip) but I'm pretty sure its the barrel (poor fit). Will be troubleshooting more after Mile High Showdown this weekend. Didn't have much time to check it so I have to switch to Limited. Link to comment Share on other sites More sharing options...
Rich406 Posted September 17, 2020 Author Share Posted September 17, 2020 (edited) It was the slide. There is either a crack I can’t find or see. Or it’s warped from all the times I’ve gotten it too hot to touch. Or maybe it’s just worn out. Either way, once I changed out the slide, things went back to normal. Edited September 17, 2020 by Rich406 Link to comment Share on other sites More sharing options...
Boomstick303 Posted September 17, 2020 Share Posted September 17, 2020 On 9/11/2020 at 10:27 PM, ltdmstr said: Well, then something has to be loose, broken or worn. If it's the rails or something in the FCU, you can't do anything about it bc that's the serial numbered part. So it can't be replaced, unless they're going to give you a new one under warranty, which I doubt. Could also be something in the barrel block. Other than that, I dunno. You can buy the FCU frames all day on Gun Broker for like $20 for anyone who is interested or needs to replace the FCU frame. It would of course have to go through an FFL. Link to comment Share on other sites More sharing options...
jwhittin Posted September 17, 2020 Share Posted September 17, 2020 I bought two a month ago. Supply is gone. Saw one listed for $100. Found an M17 version for $50 at sigsauerparts (not affiliated with Sig). OP glad you figured out what the problem was. Have you talked to a Sig about the slide? Seems like it should last longer. I can see a barrel going bad at 78k rounds. Can’t hurt to call them. Sig might replace it. Link to comment Share on other sites More sharing options...
ltdmstr Posted September 17, 2020 Share Posted September 17, 2020 3 hours ago, Boomstick303 said: You can buy the FCU frames all day on Gun Broker for like $20 for anyone who is interested or needs to replace the FCU frame. It would of course have to go through an FFL. Did not know that. Are they actual Sig parts, or aftermarket? Link to comment Share on other sites More sharing options...
jwhittin Posted September 17, 2020 Share Posted September 17, 2020 7 hours ago, ltdmstr said: Did not know that. Are they actual Sig parts, or aftermarket? The ones I bought were advertised as frames from brand new unfired factory Sig P320s. I checked the serial number at the Sig Voluntary Upgrade Program webpage and they are recognized as being official Sig Sauer products. I guess the dealers realized they could make more money selling them as parts. Link to comment Share on other sites More sharing options...
Boomstick303 Posted September 18, 2020 Share Posted September 18, 2020 (edited) I have considered buying one just to see the quality. I have also considered a 80% build. Edited September 18, 2020 by Boomstick303 Link to comment Share on other sites More sharing options...
Racinready300ex Posted October 1, 2020 Share Posted October 1, 2020 I just sold a complete FCU on GB for $550. Deals are hard to find when people will bid that high. Link to comment Share on other sites More sharing options...
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