My P-01 slide does not lock back on an empty magazine

[Oldwolf]

I am starting a new thread, based on an old one I commented in that went like this.

My comment:

I am renewing this very old thread.

I installed a Buffertech on my P-01 (built in 2008) and it has no FTE or FTF's.
However, it does not reliably lock the slide back on the last shot.
Although I can manually pull the slide back on an empty magazine and it always locks.
Is it possible/likely that the recoil spring should be replaced or the weight of the spring increased?
It throws spent casings much further than my full sized CZ 75's.
The previous owner says this P-01 has about 1000 rounds through it.

Comment: The pistol seems to be throwing spent magazines just fine, about 4-6 feet behind me on my right.

From ThompsonCustom:

Could be a spring issue but i would say a mag spring is more likely.

The follower pushes up on the slide release to lock it back so maybe its not applying enough force anymore or maybe the slide is just wore more where it caughts.

Does it lock back every time if you remove the buffer?

From me:

Good question.
The PO said the gun had no issues.
When I got it I installed the buffer before using it for the first time.
I used a steel plate magazine (14 rnd) and a plastic bumper magazine (16 rnd I think).
Next time I will remove the buffer and see what happens.

Now, with a range update.

I removed the recoil buffer and the slide still fails to lock back on the last round with all four of my compact sized magazines.
A manual pull back of the slide always results in a locked slide.
I don't see how all four magazines could have weak springs.

This gun was worked on by CZCustom in 2010. The PO reports that the CZ Custom shop installed their competition hammer, polished the internals, and smoothed out the action. They also installed a lighter spring package for self defense. This lightened the trigger pull weight but still provides reliable ignition with all primers. They are also the ones that installed the Meprolight sights.

So what should I take as the next step to solve this?
1) I could try a full length magazine from my other guns. If those work, then it could be a magazine spring problem.
2) I am planning to buy a few more compact sized magazines anyway, so, I could go ahead and get them to see if new mags solve the issue. If they do, then perhaps it just old springs in my magazines that are causing the issue.
3) Switch around slide stops from other CZ75's.
4) Check the slide notch were the slide stop locks in it.
5)?

The pistol is very accurate and I can shoot nice tight patterns with it. The trigger is great. So the only thing I need to figure out is this slide lock problem. Then I will be 100% happy.
I plan to use this gun in my CCH class next week.
Thanks in advance for you ideas.

[Rutherford2]

Here are some ideas of other things you can check for. Some of these are more likely than others, for example, it is pretty unlikely that your slide stop spring is the culprit, but if all else fails it can't hurt to look at.

1. Ammo. What ammo are you using? If it is underpowered, it may not provide enough force to operate the slide far enough back to engage the slide stop.

2. Recoil springs. Goes with ammo. What weight recoil spring are you using? If it is either too light or too heavy, it can cause problems. If it's too light, the slide could be "bouncing" preventing lock back, and if it's too heavy, you would have the same issue as #1.

3. Magazines. Brand, springs, age/use, dirt/grime.
3a. Brand matters. Use CZ factory or MecGar. Promags are crap. The MecGar 17 rounders (with anti friction coating and blue followers) have a stiffer spring than the CZ factory mags and may help.
3b. Springs. As you noted, using a stiffer magazine spring (i.e. from Wolff) may help.
3c. Age/use. If the springs or followers are severely worn, consider replacing them. Also, if the notch on the magazine that engages with the magazine release is worn out, it can allow the magazine to move and cause issues. In that case, get a new mag or a new tube.
3d. Dirt/grime. Dirt, grime, oil and anything else causing the follower or spring to hang up can cause issues. Clean them up and rub the inside down with Armor All (slicks it up, doesn't penetrate and helps keep dirt from sticking).

4. Mag release. Just like above, if your mag release is worn it may allow the magazine to move slightly. Similarly, if the spring that holds the magazine release is not installed or tensioned properly with the screw inside the frame, it may allow the magazine to wiggle.

5. Slide stop spring. If you have a screwy spring, it could cause the slide stop to hang up. I haven't personally seen one of these wear out, but if the pistol has been taken down and reassembled a lot, or if the spring was out of spec from the factory, it's possible that it got worn out or damaged. Similarly if the pin that holds the spring in place has an out of spec groove, it could potentially allow the slide stop to wiggle a tiny bit. I'd think this is pretty unlikely.

6. Cleaning. It is possible that you have carbon caked where you can't see it. Depending on how many rounds you have through it, it might be worth a detail strip and soak or getting in and around those nooks and crannies with a dental pick.

7. Lubrication. Not sure what lube you're using or how often you clean the pistol, but it is possible that using improper lube or a lube that cooks off easily could exacerbate the problem.

8. Grip. Although harder to do with CZs, if you are gripping the pistol a certain way you can inadvertently activate the slide stop and prevent the slide from locking back. Try it one-handed and see if the problem can be reproduced.

9. I'm sure you didn't do this, but make sure you have the P-01 slide stop. A CZ75 slide stop or SP-01 slide stop may not function properly. Also check that the slide stop hasn't been altered in any way - I have heard of some people removing material from the slide stop in order to prevent hang ups on magazines with bullets left. It is possible that the original owner modified the slide stop to solve this problem, but removed too much material.


Hope this helps!

[Oldwolf]

Greg ideas Rutherford2. I appreciate the time you took to tell me your thoughts.

I contacted the PO and told him the problem I am having. He was very surprised because he never had this issue when he owned it. This brings me to your comment #8. The PO wondered if I was perhaps riding the slide stop, preventing it from locking. He mentioned that his brother had the same problem when he shoots CZs with oversize slide stops.

So, before sitting here at the computer writing this response, I have my pistol in the grip that I find comfortable. Sure enough, my right thumb rides on top of the slide stop. So I am hoping the problem is very simple and I just need to re-position my thumb. I will try again tomorrow.

But to answer your points...

#1. I am using Magtech 115 gr. This works fine with my SP01 and 75BSA. Power is not a problem I feel.
#2 The PO indicated that it is the original factory spring. I am unsure what the weight is.
#3 The magazines are CZ and Mecgar. They are clean, although I will take them apart and run a rag through them and clean them as you suggested.
#4 The gun is in line-new condition. Mag release looks fine.
#5 Slide stop spring is tight.
#6 Gun is very clean.
#7 Lubricant is not caked on gummy, Breakfree CLP is what I use.
#8 !!! (I hope it is this simple)
#9 Looks to be the OEM slide stop.

Thanks again for your ideas. I will resolve this one way or the other!

[Rutherford2]

#1. I am using Magtech 115 gr. This works fine with my SP01 and 75BSA. Power is not a problem I feel.

That ammo should be fine, at least in my experience. I just wasn't sure if you were using mouse-burp hand loads or something.

#2 The PO indicated that it is the original factory spring. I am unsure what the weight is.

I can't remember either, but the factory recoil spring on a compact is a flat wire spring colored green.

#3 The magazines are CZ and Mecgar. They are clean, although I will take them apart and run a rag through them and clean them as you suggested.

Thumbs up.

#4 The gun is in line-new condition. Mag release looks fine.

Thumbs up.

#5 Slide stop spring is tight.

Thumbs up.

#6 Gun is very clean.

Very nice.

#7 Lubricant is not caked on gummy, Breakfree CLP is what I use.

Thumbs up.

#8 !!! (I hope it is this simple)

Fingers crossed! I usually shoot CZs with a thumb-high grip.

#9 Looks to be the OEM slide stop.

It probably is, but the slide stops for Shadow, Phantom, PCR, SP-01 and P-01 have very similar appearances externally but have slight differences. CZ lists them all has having their own part number. If all else fails, it can't hurt to try a new P-01 slide stop - it's usually a good spare part to have on hand anyway.

Good luck and please keep us posted on the outcome!

[Oldwolf]

#2 The PO indicated that it is the original factory spring. I am unsure what the weight is.

I can't remember either, but the factory recoil spring on a compact is a flat wire spring colored green.

Mine is round wire. But the gun has been through the CZC tuning shop, so, they probably changed it.

[olfarhors]

Rutherford 2 has the answer in there somewhere!
 all I would say is that IF the problem is occurring with all 4 magazines then I would be looking at the weapon in some form or the shooter, as he mentioned certain shooter induced problems.
 if factory ammo I doubt its a ammo power problem.
MY CZ P-01 and Sp-01 will run on everything perfect from 80 grain (yea playing around with 380 projectiles and milk jugs)  to 147 grain ammo, flat point, FMJ, round nose, hollow point.
MY normal ammo is 115 grain copper HP and its flawless in both weapons.

[Oldwolf]

Yes, I suspect that it is my right thumb resting on the slide stop that may be causing the problem.
I hoped to back out to the range today, but family obligations may prevent that from happening.
But, I will report back my findings ASAP after my next shooting session.

[Oldwolf]

Range Report! 

My thumb was riding the slide stop which prevented the slide from locking.
Once I concentrated on keeping my thumb below the slide stop, the gun functioned normally.

Now the problem is what to do with my left support hand. I can't get a comfy grip, feels like there is nowhere for my left hand to grip. Will have to work on that.
Never have had a compact sized pistol before, so the two hand grip on such a small gun is new to me.

[olfarhors]

HMMM!
 glad you found the problem, many have this problem when shooting my 10 MM's due to recoil.
never had a problem with my P-01, SP-01 or 97 but different shooters.
 have you considered Thumb reduction Surgery?
I might consider this myself before giving up my P-01.

[Oldwolf]

I am used to letting my thumb ride up on the manual safety of my full sized 75s.
That doesn't work so well with the P-01.

[1SOW]

You likely need to use a thumbs forward grip.
Weakhand thumb pointed at the target.  Strong hand thumb on top of weakhand pointing at the target if your hand  is big enough.  If it isn't (mine isn't with the full size CZs) then on top of the weak hand thumb pointed downrange as close as it's length allows.    but Not UP on the release.

My strong hand index finger and "SRConnector linkages" have been modified by someone other than CGW or CZC.

Sure is a pretty pistol.