kwesi Posted December 8, 2011 Share Posted December 8, 2011 (edited) New witness limited 10mm that has 1,000 rounds down the pipe. The slide would, during the first 700 rounds, occasionally lock back properly with the new K-10 mags BUT I also had 18 failure to load with the nose of the FMJ flat nose bullet pointing up & resting on the feed ramp. The failures occurred with OAL's ranging from 1.245 - 1.255. Mostly at 1.245 - 1.247 & even a few factory rounds at that same OAL. On my last outing I replaced the K10 mag springs with Wolf xtra power & loaded the rounds to 1.255 - 1.258 +/-. I ran it with the stock recoil rod/spring for the first 8 rounds loading only 1 round in each of my two mags - No lock open. Switched to Wolf 16# recoil spring & 250 rounds later still NOT a single lock open even though the slide will ALWAYS lock back when manually pulling the slide back on a empty mag! The good news is that I had ZERO failure to loads! Still not sure if this improvement is due to the OAL, Wolf mag springs, or was it just breaking in. While my main issue appears corrected I would still like the slide to lock back. I checked the slide stop but found no burrs. Any help is appreciated! Edited December 8, 2011 by kwesi Link to comment Share on other sites More sharing options...
Skydiver Posted December 8, 2011 Share Posted December 8, 2011 My guess is that the slide is not cycling back far enough with your particular load and spring combination. The fact that the slide does lock back when you manually pull the slide back is what is pushing me in this direction for a theory. Have you fired your loads over a chrono to establish your power factor? Anyway, I would try a lighter recoil spring. Or if you have added a shock buff, try running the gun without a shock buff. Link to comment Share on other sites More sharing options...
Skydiver Posted December 8, 2011 Share Posted December 8, 2011 Looking through old posts... you mentioned that your 10mm loads go 1100-1200 fps. Instinctively, I think that should be more than enough to cycle the slide fully. Additionally, I'd inferred that you were using a Springco with an 18# spring. In your post above, you mentioned going back to the stock spring, as well as a 16# spring. Were those with the Springco, or did you also go back to the stock guide rod? It's not likely since you already regularly shoot full power 10mm, but I was going to ask about grip technique and make sure that you aren't riding or accidentally bumping down the slide stop during recoil. (I used to do that shooting my G-34 shooting factory 9mm.) Link to comment Share on other sites More sharing options...
kwesi Posted December 8, 2011 Author Share Posted December 8, 2011 (edited) Skydiver: My ave FPS at 8.5gr (1.250 OAL) was 1,188. I reduced the above loads to 8.2gr (1.255 - 1.260) so I believe we are 1100+. I was not using the Sprinco. Until the last outing everything tested was all factory (14.5# recoil spring). After eight individual rounds did not lock open I then switched to the Wolf 16#. I really doubt that I'm bumping the slide stop. Edited December 8, 2011 by kwesi Link to comment Share on other sites More sharing options...
Nealio Posted December 8, 2011 Share Posted December 8, 2011 Why do none of you 10mm guys every post the bullet weight??? I'm guessing 180gr. Have you cleaned your mag tube and follower? When my tube and/or follower get sooty from a lot of use I get failures to lock back. After I clean them everything starts working again. Link to comment Share on other sites More sharing options...
kwesi Posted December 8, 2011 Author Share Posted December 8, 2011 Nealio: 180gr FMJ. I cleaned the mags for the first time prior to my posted results. Can the powder burn rate be a factor? I'm using Power Pistol. Link to comment Share on other sites More sharing options...
Nealio Posted December 9, 2011 Share Posted December 9, 2011 All I use is power pistol and all of my guns lock back. The 10mm is a little more finicky than the rest, probably due to the Sprinco. The only times I've had my guns not lock back it was due to one of the following: rails were dirty, causing increased friction which lead to a slight short stroke spring was too heavy causing short stroke (9mm) mags were caked with soot, not allowing follower to pop up quick enough Now that I got my spring weight correct, my 9mm even locks back with the Grams followers (which I read it wasn't supposed to..?) Could it be your slide stop is dirty? Also on my 180gr loads I think I was running 9.0gr of PP Link to comment Share on other sites More sharing options...
kwesi Posted December 9, 2011 Author Share Posted December 9, 2011 Nealio: I clean her after every outing except for the mags but even those were cleaned. Given my loads which recoil spring would you use? A friend suggested the Wolf mag springs expecting that to correct the lock back. The next to last outing the slide did lock back 3-4 times with the factory mag springs. I will test that way next week. Link to comment Share on other sites More sharing options...
gerritm Posted December 9, 2011 Share Posted December 9, 2011 Check your spring/follower in your mag. I had that same problem with my old style 9mm and .45 mags. It was the spring and follower not lining up and moving up high enough to catch the inside slide stop. Took out the springs and followers and adjusted the angle that the follower hits the stop and it works. Something I had to do on a regular basis with the old style mags. I don not have any problems with the new Mec Gar mags. Link to comment Share on other sites More sharing options...
CHA-LEE Posted December 9, 2011 Share Posted December 9, 2011 Start simple. Put an empty mag in the gun and rack the slide. It should lock back. If it does not, the follower is not pushing the slide lock lever up properly to lock the slide back. Are you using stock followers? Link to comment Share on other sites More sharing options...
kwesi Posted December 9, 2011 Author Share Posted December 9, 2011 Cha-Lee: stock followers and yes it locks back every time on an empty mag! Link to comment Share on other sites More sharing options...
CHA-LEE Posted December 9, 2011 Share Posted December 9, 2011 Then your mag springs are too weak. Try some extra power mag springs. The slide speed is probably so fast that its coming forward past the slide lock position before the follower starts pushing up on the slide lock lever. Its either that or the slide lock lever to slide notch engagement is marginal and its "dropping out" of slide lock due to the violent recoil of the 10mm rounds. Usually if this is the case you can get it to drop the slide by seating a mag aggressively when its slide locked. Start with dummy rounds so you can test this on the bench at home. If you can cause the slide to drop when seating a mag hard, the slide lock lever to slide notch engagement is marginal. Link to comment Share on other sites More sharing options...
kwesi Posted December 9, 2011 Author Share Posted December 9, 2011 Cha-Lee: as posted above I did use the Wolf xtra mag springs in both mags! Link to comment Share on other sites More sharing options...
kwesi Posted December 10, 2011 Author Share Posted December 10, 2011 Then your mag springs are too weak. Try some extra power mag springs. The slide speed is probably so fast that its coming forward past the slide lock position before the follower starts pushing up on the slide lock lever. Its either that or the slide lock lever to slide notch engagement is marginal and its "dropping out" of slide lock due to the violent recoil of the 10mm rounds. Usually if this is the case you can get it to drop the slide by seating a mag aggressively when its slide locked. Start with dummy rounds so you can test this on the bench at home. If you can cause the slide to drop when seating a mag hard, the slide lock lever to slide notch engagement is marginal. I loaded up the dummy rounds and tested both mags with the factory mag springs AND Wolf xtra power mag springs: all it took was a sharp hand butt and the slide closed EVERY time. Now what? Link to comment Share on other sites More sharing options...
CHA-LEE Posted December 10, 2011 Share Posted December 10, 2011 You need to modify the angle of the slide release lever so that it engages the slide lock notch in the slide more securely. You may have to change the angle of the notch in the slide as well. These two pieces should butt up against one another with flat surfaces that fully contact one another. If one side or the other has a funky angle to it they will not be engaging flat surface to flat surface which leads to this unwanted slide drop issue. Without seeing it first hand I can't give you much more advice than that. Link to comment Share on other sites More sharing options...
kwesi Posted December 10, 2011 Author Share Posted December 10, 2011 A modifier I'm not...wish I was that handy. My buddy has the same gun in 40 S&W so I guess I can try his and see if that solves the issue then decide from there. Thanks! Link to comment Share on other sites More sharing options...
CHA-LEE Posted December 11, 2011 Share Posted December 11, 2011 Well, at least you know what your problem is. Get it to a gunsmith so they can fix it for you. Link to comment Share on other sites More sharing options...
kwesi Posted December 13, 2011 Author Share Posted December 13, 2011 My gunsmith played with it for a while then recommended replacing it. Hope to have it by the weekend. Hope it doesn't need to be "adjusted" to fit. Link to comment Share on other sites More sharing options...
CHA-LEE Posted December 13, 2011 Share Posted December 13, 2011 Replacing what? The slide stop lever? Link to comment Share on other sites More sharing options...
kwesi Posted December 13, 2011 Author Share Posted December 13, 2011 Yes Link to comment Share on other sites More sharing options...
Mo Hepworth Posted December 13, 2011 Share Posted December 13, 2011 (edited) if your "gunsmith", recommends replacing a slide stop, instead of trimming or reshaping it....I would get another gunsmith. I am not an expert, but even I have no issue reshaping or trimming a slide stop...my LImited Custom was locking back with 1 or 2 rounds in the magazine....I trimmed the bottom of the slide stop by about 1.5, to 2mm....problem fixed. In your case...you want it to lock back more aggressively...perhaps reshaping the top inside of the slide release lever...or install a slightly lighter recoil spring... Edited December 13, 2011 by Mo Hepworth Link to comment Share on other sites More sharing options...
CHA-LEE Posted December 13, 2011 Share Posted December 13, 2011 if your "gunsmith", recommends replacing a slide stop, instead of trimming or reshaping it....I would get another gunsmith. I am not an expert, but even I have no issue reshaping or trimming a slide stop...my LImited Custom was locking back with 1 or 2 rounds in the magazine....I trimmed the bottom of the slide stop by about 1.5, to 2mm....problem fixed. In your case...you want it to lock back more aggressively...perhaps reshaping the top inside of the slide release lever...or install a slightly lighter recoil spring... +1 Get a new gunsmith. Adjusting the profile of the slide stop edge that engages the notch in the slide is very easy. Unless the corner that engages the notch in the slide is totally damaged beyond repair there is no reason why he shouldn't be able to get the existing one to work. Even if the part was damaged he could simply weld on more material then reshape it as needed. I vote for finding a competent gunsmith that will actually work on your gun to make it work verses push back and make you buy parts instead. Link to comment Share on other sites More sharing options...
Nealio Posted December 13, 2011 Share Posted December 13, 2011 This gun only has like 1000 rounds through it, doesn't it ? Link to comment Share on other sites More sharing options...
kwesi Posted December 13, 2011 Author Share Posted December 13, 2011 The gun has about 1,100 rounds down the pipe. The smith is the fellow at my local range that handles repairs. I would not expect him to weld anything. He did use a file and tried to modify it then tested by Cha-Lee's method of agressively inserting the mag but the slide kept closing. It was at that point that he showed me where the occured that was the issue. Sorry guys but I'm just not that mechanically inclined to explain it any better. If the new slide stop does not lock it back then I guess I will have to find someone else. I can't go lighter on the recoil springs - even the factory 14.5# failed to lock it open. I'm just waiting to resolve this then I want to add my Sprinco guide rod to see how she runs since many of my loads are approaching 1200 fps. I started loading last night with a new powder, Blue Dot @ 10.3 - 10.6gr. BTW: isn't it possible that, since these come fitted from the custom shop, that the slide stop may have been over adjusted for fit from day 1? Link to comment Share on other sites More sharing options...
CHA-LEE Posted December 14, 2011 Share Posted December 14, 2011 (edited) Changing recoil spring weights to solve this problem is the wrong approach. If the slide lock lever is working properly it shouldn't matter what recoil spring you are using, it should work with any recoil spring. Changing to a heavier recoil spring is just a bandaid to mask the real problem. Fix the real problem (slide lock lever to slide lock notch in the slide engagement) and you can use whatever recoil spring you want. The reality here is that these guns are mass produced. Most of the parts need to be fitted to one another in order to work properly. Some times things don't get fitted together properly on mass produced things. These parts are not Lego pieces that simply snap together in one place and magically work. Your "Gunsmith" will have to tune these parts to fit together properly in order to make the slide locking after the last round feature function 100%. As said before, if your current "Gunsmith" can figure out this simple task, then take it to a real gunsmith who can make it function properly. Edited December 14, 2011 by CHA-LEE Link to comment Share on other sites More sharing options...
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