Glock keyholing?

R

Radny97

New member
I went to the range today to test some accuracy upgrades that I had made to my Canik T120. I wanted to have a base level of accuracy to compare my gun to with its recent improvements. The range that I have a membership at gives me free rentals so I rented a Glock 17 and Glock 19 (both generation 4) to compare with my Canik on accuracy. I had some premium factory ammo for the long distance accuracy test. And some very cheap bulk reload ammo for the high speed close up tests I was running.
While i was running these tests I noticed something very interesting. When shooting the cheap reload ammo both Glocks had problems. They repeatedly did not lock back to slide on an empty mag. And the bullets were keyholing the target at distances as close as 5 yards. Both Glocks exhibited the same problem which was interesting to me because it meant that it was not just that one particular gun but perhaps a platform issue. Maybe it has to do with polygonal rifling? My Canik had no problems with either the slide or keyholing. (It has land and groove rifling)
Has anyone else seen these types of problems with Glocks?

For the record I'm not a Glock hater. I find them to be reliable and reasonably accurate duty firearms, which is why I was using them as a baseline for my accuracy tests.
 
Were your targets attached to a firm backing? Hanging unsupported paper often leaves ragged holes despite no keyholing.

Did you check the Glock barrels to make sure they were rifled? :)
 
The combination of the slide not locking back and the inaccuracy tends to point in the direction of underpowered ammo. The slide is not locking back because it is not coming back far enough, and the weak charge is failing to upset the bullet enough to properly fill the Glock rifling. The ammo might work OK in other guns, but apparently not the Glock, or at least the Glocks you used.

Of course there could be other problems, like undersize bullets, but I tend to think a light powder charge. If the range loads its own ammo, it might load down to save money or if many of its customers are neophytes who might be sensitive to recoil.

Jim
 
Ha-ha! I have to admit that I did take down the 19 and check the barrel to see if there was a problem. It was clean and looked good.
The targets were not supported but if that were the issue the Canik should have had similar issues.
Here's a pic of the keyholing. It's pretty bad.
It very well could have been underpowered ammo. Is it harder to get a good seal on polygonal rifling, thereby making it more sensitive to underpowered ammo?
 

Attachments

  • 2015_120221_1721_950.jpg
    2015_120221_1721_950.jpg
    129 KB · Views: 218
Last edited:
I've never seen keyholing that bad out of any pistol. I've shot some pretty weak reloads from a friend out of my Glock and they didn't always lock the slide back, for the reasons James touched on, but never keyholing.
 
That looks more like unsupported target rips than keyholing to me. I've seen similar targets at the range where I used to shoot, where we just stapled the target between two boards. I learned to bring my own cardboard backing.
 
That's a keyhole. It's probably the ammo. I have had that problem with some of my lead reloads with my CZs by the way.
 
Please explain what you mean by "cheap reload ammo"? I doubt that your LGR intended for anybody to shoot cheap reload ammo through their rental guns, don't they usually make you buy their boxed factory ammo to try out their rentals?

Coincidently, a while ago I was shooting a borrowed Canik T120 alongside my own Glock 17. The T120 jammed repeatedly on steelcase TulAmmo 9mm. I would not want to shoot that ammo on a regular basis, but it was the only ammo I brought in my range bag that day and my G-17 did shoot that ammo without problems.
 
Are you shooting unjacketed lead out of your Glock? If so, you could have a lead fouling issue. Also, you might check the barrel muzzle and make sure you haven't damaged it in some way.

Good accuracy with my Glock 17 is something I've never been able to achieve, but I've never had a keyholing problem. Just off-center and doesn't group well. But, it works, always works and has never failed. It's a good travel gun for when I'm driving 6+ hours.
 
The one round does look like a key hole, the others do not. Were there others like the bottom hole in your pic, or is it the only one?

Theres always the possibility that there was/were some imperfections in the bullet(s). Type of bullet may make a difference as well. Ive just recently started using Berry's plated bullets, and they recommend specific velocities and crimping procedures. They say tumbling bullets is one of the results of not doing so.

Glocks do like hotter loads, and often wont cycle properly, with loads other guns seem to not have an issue with. I went through this with the first Glock I bought back in the 80's. My reloads that cycled my High Powers, P38, HK P7, etc, would not reliably cycle the Glock. I had to bump the load up to accomplish that.
 
Glock's polygon rifling has been known to have problems with lead bullets. That keyholing profile looks like a heavyweight bullet. Loaded to low velocities and with the lower friction of poly rifling, it probably did not get going fast enough to stabilize.
 
And some very cheap bulk reload ammo
Click to expand...

When shooting the cheap reload ammo both Glocks had problems. They repeatedly did not lock back to slide on an empty mag. And the bullets were keyholing the target at distances as close as 5 yards.
Click to expand...

but perhaps a platform issue. Maybe it has to do with polygonal rifling?
Click to expand...

Cheap reloads. I don't blame the Glocks at all.
 
I had maybe 15 keyholes out of 50 shots with that ammo from the two Glocks. The Canik was not keyholing with the same ammo. They were definitely keyholes as some shots were slowfire and the target was not moving.
No question that the problem was with this crappy ammo, but it was interesting that the Glocks were having such problems with it comparatively. I did notice that the Canik also suffered some accuracy issues with the same ammo, but not as bad as the Glocks and no keyholing.
A little about the ammo. I bought a bulk reload bag of 1000 at a gunshow. It is mixed headstamps. The bullets are fmj 124 gn. Not lead. The cases appear to have no crimp as the bell at the case mouth has not been addressed. It also appears to me that no resizing die was used before the cases were loaded. Like I said, really crappy ammo. (Needless to say I won't be buying more and will be much more careful with bulk ammo purchases in the future.)The Canik did have some failures to feed because of the case mouth bell\no crimp issues. The Glock 17 had a few failures to feed too but not as bad as the Canik.
I'm on great terms with my range owners so even though they don't let most shoot their own ammo through the rentals they bend the rules for me.
I would have just shrugged my shoulders if only one Glock had the issue. When both did I knew there was something with this ammo that the Glocks did not like. Still puzzled as to what that might be, but poor crimp, poorly sized bullets seem likely culprits. I don't think the loads were underpowered because recoil seemed the same from the factory loads I was shooting too. But that's a possibility.
 
I know the attraction of a bargain, but I long ago made one resolution.

The only reloads I shoot are my own. That way, if something goes wrong, I know where the reloader lives and I can go kick him in the pants.

Jim
 
The cases appear to have no crimp as the bell at the case mouth has not been addressed. It also appears to me that no resizing die was used before the cases were loaded. Like I said, really crappy ammo.
Click to expand...

Wow, and you still shot them?
 
Well, I don't really want to sell them to some other poor sap, and its hard to stare at a big pile of ammo in your house and not go out and shoot it. :)
 
The cases appear to have no crimp as the bell at the case mouth has not been addressed. It also appears to me that no resizing die was used before the cases were loaded. Like I said, really crappy ammo.
Click to expand...
I'm on great terms with my range owners so even though they don't let most shoot their own ammo through the rentals they bend the rules for me.
Click to expand...
Better hope they don't read this thread... :eek:
 
The only reloads I shoot are my own. That way, if something goes wrong, I know where the reloader lives and I can go kick him in the pants.
Click to expand...

OP, read what the man says here, We want to make sure you still have your shooting hand intact and functional so you can keep shooting and posting on TFL!

I'm on great terms with my range owners so even though they don't let most shoot their own ammo through the rentals they bend the rules for me.
Click to expand...

I hope the range owner's underwriter for liability insurance doesn't read this thread!
 
Last edited:
You must log in or register to reply here.
Back
Top