Glock 34 13# spring & slide lock

[nuclearmonkey]

Brand spanking new here, but was wondering if someone has had experience with this: I am running a 13# ISMI spring in my 34 with a Vanek trigger. I am shooting 147gr minor loads in idpa & ipsc. Only problem is that slide lock on an empty mag is a ? About 30% of the time I am failing to go to slide lock on an empty mag (30% of the time too much for idpa) I have since switched to a flat slide lock lever, went to the range, and still had issues (most noticibly when doing more active drills where speed was involved) I have no ideas, but the only thing i can think of is the spring. I have not had the chance to test the stock spring again, but am dreading having to go back since I love the way it shoots with the 13. Any help / advice would be greatly appreciated!!

Thanks in advance,

NM

[Duane Thomas]

Have you chronoed the load? Sounds to me like it's not generating enough energy to fully operate the action. What sort of mags are you using? I've noticed the 10-rounders are not 100% on lockback, but I've never had a problem with 17-rounders.

[buddy_fuentes]

Have you tried any other loads to make sure that your load has enough power to cycle your slide?

I have a 34 with everything lightened, I use a soft feeling 147 grain lead RN load. It has a 142 PF, but you would never guess it. Slide cycles fast.

Buddy

[kevin c]

Have you tried any other loads to make sure that your load has enough power to cycle your slide?

I have a 34 with everything lightened, I use a soft feeling 147 grain lead RN load. It has a 142 PF, but you would never guess it. Slide cycles fast.

Buddy

+1 on the PF Buddy uses.

Both my production loads (9mm 147 gr, and minor 40S&W 180 gr) are also well over the PF floor, and are very soft, but still cycle the 15# ISMI's I use because I've had problems with the slide coming out of battery when I slam home a reload.

135 to 145 PF still is nothing compared to the 170 PF I load to in Limited.

Just my two cents...

[nuclearmonkey]

Thanks for all of the replies... it's funny how until I started reading some of the posts on this forum, the PF was the last thing I would have thought of. I am relatively new to the competition aspect, so still ramping up on loads, etc. I do know that the loads are from a local club guy here in south florida who supplies most of the better ipsc guys. I will try and borrow a chrono from a friend to test the PF. One question though... wouldn't the lighter the recoil spring, essentially the softer the ammo you could shoot - since the slide cycles faster? I will post the PF when I get it - maybe that might answer the question (but someone will definitely have to tell me what the end result would mean ) Also, I am using the 17rd glock mags (only a couple of months old - so I think that makes them the latest generation)

Again, thanks for the help - hopefully will get this ironed out soon. BTW, does anyone know the PF for Atlanta Arms' 147 reloads are? - I just bought a case but haven't tried them yet.

Cheers,

nm

[chrisa006]

2 things you probably have already thought of. A shock buff will cause it and the extended slide release can get hit by you thumb in recoil.

[buddy_fuentes]

Call Atlanta Arms and get them to give you an approximate velocity of the ammo you purchased. I feel sure that their ammo is not the culprit. Multiply the bullet weight times the velocity and divide by 1000.

Example:

1000 Feet per second x 147 grain bullet= 147,000. Divide that by 1000 and you get a power factor of 147.

The lighter spring should give your slide more velocity, but I have seen where a light spring messes up the timing. As stated above, sometimes your slide can get pushed out of battery and cause misfires.

I have done things with a 1911 and they worked fine and then tried it with a Glock, only to scratch my head and wonder what is wrong. The most important thing is to have you gun running reliably. A sweet trigger and good sights are next.

Good luck, Buddy

[Flexmoney]

Your ISMI spring could be having coil bind and limiting the slide travel.

Compare the slide travel to that of a stock recoil rod and spring. (It may be about a quarter of an inch difference.)

[nuclearmonkey]

Your ISMI spring could be having coil bind and limiting the slide travel.

Compare the slide travel to that of a stock recoil rod and spring. (It may be about a quarter of an inch difference.)

Thanks for the suggestion - I am not too sure how to go about measuring this, so this is what i did: I put the stock spring in (uncaptured - but with the stock guide rod) and measured back from the tip of the barrel to the back edge of the slide as far as I could possibly pull it back. I then did this again with the ismi spring in it. The measurement was the same (9 5/8 '' for whatever that is worth). Now as far as slide travel during actual blowback, I am not sure how that would compare, but I would imagine it should be pretty similar. The hardest part is that I can't forcibly duplicate it. It fails to go to slide lock at inoportune times when I least expect it. If i load a mag with two shots and fire trying to see if it will happen, it works fine - It's when I am in the middle of paying attention to something else that it usually happens, so it's hard to try different fixes to find out if it indeed the fixes work.

As for Atlanta Arms, I have not used their ammo yet, but am going to give it a try tonight.

As soon as I get a PF, I will let you guys know - maybe that might explain something - now that I think about it, I seemed to have been having more noticible problems with slidelock with the 14# wolf than the 13# ismi (maybe 70% failure as opposed to 30% to lock back) - sorry for all of the confusion, I am really trying to learn as I go!

Thanks again for all the help!!

nm

[Flexmoney]

I have since switched to a flat slide lock lever, went to the range, and still had issues (most noticibly when doing more active drills where speed was involved)

The could very well be a shooter induced issue. Especially since you notice it happening more when you are speeding along.

[nuclearmonkey]

I have since switched to a flat slide lock lever, went to the range, and still had issues (most noticibly when doing more active drills where speed was involved)

The could very well be a shooter induced issue. Especially since you notice it happening more when you are speeding along.

Could very well be ... Just not sure what I could be doing. I am fairly positive that it's not me hitting the slide release lever - not sure what else it could be. I am running slide glide in it - maybe the glock is a bit too wet. I did find out that the ammo I am using has a PF around 130. Also, the Atlanta arms ammo has a PF around 128-130. Not sure if that matters much. I do know that plenty are using the same ammo with xd's and glock's, etc and no problems that I know of. Going to try the stock spring, as well as a 12# wolf. I wonder if logical progression might work here - (more problems with 14, less with 13, maybe 12 might do it). Will also try the Atlanta Arms ammo tonight for a first.

Thanks!

nm

[buddy_fuentes]

I read the same thing that flex did. You need to have the first joint of your right thumb removed. As with all medical advise you should get a second opinion.

I think it could be hitting the slide release. Let someone else shoot the gun and see if they are have the same problem. If they aren't and you are not up for the surgery, you might try to file the slide release down and then polish it. Make sure you don't have one of the extended slide releases installed, that could be a problem.

Good luck, Buddy

[Flexmoney]

...you might try to file the slide release down and then polish it.

That will bump you right out of Production division. (external modification)

[buddy_fuentes]

I guess it is the thumb that has to be modified.

Buddy

[Duane Thomas]

One question though... wouldn't the lighter the recoil spring, essentially the softer the ammo you could shoot - since the slide cycles faster?

Actually, my impression is that the gun cycles faster with a heavier recoil spring. A lighter recoil spring, by contrast, can give the slide a serious "chunk-chunk" effect in recoil.

[SA Friday]

I had some issues when I first built up my 130 pf loads with 147 gr bullets. The slide just wouldn't kick out the brass. I ended up testing cutting coils off of the 13 lb spring until I got it to reliably eject the brass. I ended up cutting 3 coils off. This doesn't necessarily change the spring weight, but does change the stroke distance (much like Flex was talking about when he recommended measuring the springs when compressed). I don't have this problem in my Glock 17, and run an uncut spring. The G34 has a heavier slide.

I DO NOT advocate this if you are not WELL experienced in the Glock inner workings. It can cause the slide to have issues going into battery, especially if you don't change the spring out often. You have to know how to and check often for the spring becoming too worn for reliable function. You might have this same issue with a 12lb spring too. Be Careful.

The one thing I will suggest is having someone videotape you shooting a match, especially from the left side, and see if you can catch what's going on that causes the slide to not lock open. You could be riding the slide, thumb on the lever, or the slide is short-stroking. All of these can be caught on video.

[driver8M3]

I had some issues when I first built up my 130 pf loads with 147 gr bullets. The slide just wouldn't kick out the brass. I ended up testing cutting coils off of the 13 lb spring until I got it to reliably eject the brass. I ended up cutting 3 coils off. This doesn't necessarily change the spring weight, but does change the stroke distance (much like Flex was talking about when he recommended measuring the springs when compressed). I don't have this problem in my Glock 17, and run an uncut spring. The G34 has a heavier slide.

+1 to all of that.

i just changed my 34 spring after about 2 years (~20 rounds) b/c i started having ejection issues. however, i'm not sure if it was the recoil spring, which indeed was a bit compressed, or the crud that was piling up on the extractor (i changed the spring and cleaned the gun at the same time).

[nuclearmonkey]

I had some issues when I first built up my 130 pf loads with 147 gr bullets. The slide just wouldn't kick out the brass. I ended up testing cutting coils off of the 13 lb spring until I got it to reliably eject the brass. I ended up cutting 3 coils off. This doesn't necessarily change the spring weight, but does change the stroke distance (much like Flex was talking about when he recommended measuring the springs when compressed). I don't have this problem in my Glock 17, and run an uncut spring. The G34 has a heavier slide.

I DO NOT advocate this if you are not WELL experienced in the Glock inner workings. It can cause the slide to have issues going into battery, especially if you don't change the spring out often. You have to know how to and check often for the spring becoming too worn for reliable function. You might have this same issue with a 12lb spring too. Be Careful.

The one thing I will suggest is having someone videotape you shooting a match, especially from the left side, and see if you can catch what's going on that causes the slide to not lock open. You could be riding the slide, thumb on the lever, or the slide is short-stroking. All of these can be caught on video.

Thanks for the suggestions - I also have a call in to Matt at Custom Glock since I know he is running this setup. As for user error, it very well may be - I really need to find some time in the next day or so to sit with a bunch of ammo and springs, and try to isolate the problem. I shot last night without issue (although there were only a half dozen times I was able to run the gun to empty). Difinitely need to experiment with not so great grips and see if maybe it's happening when things get sped up - maybe my grip is changing without me knowing it. The video is great advice - A lot of people have been mentioning that lately about helping out shooting as a whole, so it will definitely be something I will look into. As for the thumb, i will try and work this out in the next week or so... if not, I might pm you to find a good doctor!

Thanks again for all of the help - it's great to hear so many potential causes - now at least I have an idea of what to try, and what to look for!!

Cheers!

nm

[Duane Thomas]

BTW, the extended slide release on the G34 should be instantly changed out for a G17-type flat release. The extended release is more trouble than it's worth.

[nuclearmonkey]

BTW, the extended slide release on the G34 should be instantly changed out for a G17-type flat release. The extended release is more trouble than it's worth.

Thanks Duane - did that first to try and eliminate as much user error as possible. Went to the range tonight for about an hour - couldn't get it to screw up once. Tried speeding up, only loading a couple at a time, burning thru a mag.. still no problems at all - will see how it holds for idpa match this weekend.

nm

[Glockster35]

I am interested in how this turns out. Last time I shot my G35, was before I made any major changes to it.

I have since added a new Storm Lake barrel, Dawson Super-Heavy Mag Well, Warren tactical rear sight and F/O front sight, 6 new gen magazines with Arredondo +5 extensions and followers.

I am awaiting a Novak guide rod for the G35, new springs and a JP Enterprises extended mag release.

For ammo, I will be starting out with the Winchester White Box, until I can find someone locally to re-load for me.

Last time I shot the pistol, I had no problems, until I added my TLR-1 light to it, then the magazines were not feeding properly. I attributed this to the added weight of the light, and I will have to test further to overcome this!

[Midas]

I use a 13lb IMSI spring in my 34 set and have had virtually no problems.(Knock on Wood :-)) .As a mater off fact I have it on both my 34's. I run Atlanta Arms 9mm 147 Jhp that have about 135 power factor at Sea level in a moderate climate.

Now that I have said this I hope I don;t jinx myself.

[Joe D]

I have gotten away from the 13# ISMI spring and run a 12# Wolf instead.

[nuclearmonkey]

Just wanted to give everyone a follow up (for those interested) and let you guys know that all problems have miraculously stopped. I don't really know why, but I can say that (knock on wood) I have shot an idpa match - and all four stages went to slide lock, and just finnished up a 3 day course with Randy Cain - and not one hickup. I have no idea what may have been causing the issues (I am running the gun a bit dryer - someone mentioned maybe some slide glide managed it's way over to the slide lock area). I know Charlie Vanek was mentioning the 12 lb wolf springs - I ordered two, but have not tried them yet since things seem to working better. I do hate how the wolf sounds in the gun due to it's length though. It sounds like a built up slinky that rubs on the slide since it is so stacked up. For those of you running the 12lb wolf, have you trimmed them at all, or live with the extra bunched up inside?

Again, thank you all for the suggestions, now I just hope it keeps running as well as it's been!!

-nm

[Joe D]

I use a large diameter plastic guide rod or large dia. steel rod. It will work fine with the stock plastic rod. You just can't capture it. No need to trim the spring.