Jump to content
Brian Enos's Forums... Maku mozo!

Slide does not lock open after last round?


kwesi

Recommended Posts

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 by kwesi
Link to comment
Share on other sites

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

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

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 by kwesi
Link to comment
Share on other sites

Why do none of you 10mm guys every post the bullet weight??? :wacko: 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

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

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

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

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

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

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

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

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 by Mo Hepworth
Link to comment
Share on other sites

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

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

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 by CHA-LEE
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...