JayB059

OK, gotcha ... thanks for the explanation, I see it now in your pictures ... I just automatically assumed the dimensions were the problem. I will have to look into that Para mag release you referenced from Slade Street Tactical. Thanks!

Which model # do you have? I know the model #'s on their website, i.e. 51738 -> https://armscor.com/firearms/pro-series/pro-match-ultra-hc-40sw/ , are nowhere to be found on the actual gun (that I'm aware of). Did you by chance measure your trigger pull weight? I just measured mine with a Wheeler scale (https://www.wheelertools.com/gunsmithing-tools/guages-and-scales/professional-digital-trigger-gauge/710904.html#start=1) and my 10-pull average came out to be 2 lbs. 5.6 oz. I did get this gun lightly used from the forums, so not sure if anything was done to it previously ... the beaver tail safety has been deactivated, that I know, just don't know which method was used, i.e. it's not pinned, so I assume something was cut off in the inside. As I look closer at the rear of the magwell on mine, it seems that it might have been filed slightly for the same reason you mentioned ... never noticed that before

OK, thanks for confirming that was what you got from Dawson. In your picture, which one was your stock RIA and which was the Dawson? I'm guessing the top one was stock, which from your picture, appears to be wider/thicker than the other one. Do you happen to have any dimensions? I tired Googling what the standard 2011 mag release dimensions where, and I was not able to find anything other than the length the button protrudes past the frame, so I can't compare to know if the RIA one I have is thicker or not. Here's some of the dimensions I took of mine ... not sure if I'm using the correct terminology or not: overall length = 1.3085" main body thickness (half circle) = 0.1860" main body thickness (full circle) = 0.3080" --> I think this is the dimensions shown in your picture Note that I'm trying to use STI Gen 1 mags and I'm getting some issues with them locking properly when the mags are loaded (with any number of rounds, not just full). Mags have been tuned per Dawson specs. It seems that others have successfully used the STI Gen 1 mags with this "same" RIA before, but not sure what additional measures were needed. It seems that RIA makes some subtle changes here and there and not sure if those are reflected in the model #'s or not. One example of this is my rear sights are blacked out, as shown here: https://www.youtube.com/watch?v=Nh25RICs8xM ... but a review for the "same" gun from 2016 here: https://www.thetruthaboutguns.com/gun-review-rock-island-armory-pro-match-ultra-40-10mm-1911s/ shows the rear sights with two white dots. Just using that as an example to essentially say that someone else with the "same" gun might get something to work that someone else might not be able to get work (without some additional mods).

Which part # did you buy that didn't work? This one -> https://dawsonprecision.com/mag-releases-sti-2011-by-dawson-precision/ has two reviews on their site with people saying it worked fine in their RIA ... one review is from September 2018, and one is from February 2020, the latter stating he has a 10mm Pro Match Tac Ultra HC. I'm asking because I have a .40 Pro Match Ultra HC (51738) that I was looking to replace the mag release on and was interested in that Dawson. Thanks.

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.

@BryceA, where did you see/find a 1911 Max in .40? Only the 9mm and .45 are listed on Sig's website ... I know it's been that way since November, so I'm thinking they are no longer making it in .40, but I assume there are some still out there, just harder to find now?

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.