Glock 21 gen4 locks up pretty badly [Archive] - Glock Talk


View Full Version : Glock 21 gen4 locks up pretty badly

11-19-2012, 12:06
When I load the G21 gen4 with the Hornady 45 Auto +P 200 gr TAP FDP the gun locks up pretty badly.

Meaning there's simply no way to move the slide back without major force. What I have to do is push it with all my body weight against the edge of a table and force it open that way.

This has not happened with any other ammo, hollow point or fmj.
When I load these very same rounds in my 1911's I have no problems.

The oal on these cartridges is 1.30 inches in most cases. The oal on all my reloads and most other brand name brass I use is 1.25 but I doubt it's enough to completely lock up the gun like that
Once I take these rounds out and load it with anything else the slide opens normally.

Has this happened to anyone else?

11-19-2012, 12:13
How does it shoot?:supergrin: Dont judge your ammo like this.

11-19-2012, 12:29
Are you talking about a chambered live round requiring that level of force to cycle the slide manually to remove?
If so, you have a definite problem somewhere.

11-19-2012, 12:48
Are you talking about a chambered live round requiring that level of force to cycle the slide manually to remove?
If so, you have a definite problem somewhere.

Yes, that is exactly what I'm talking about.
Chambered live round requiring that level of force to cycle the slide.
100% correct.
I couldn't believe it. Once I finally got the round out I put some fmj's from other manufacturers and the gun operated normally.

11-19-2012, 12:55
Hornady ammo sucks, LOL.. Id either contact Hornady about it or just use it in your other gun, and get a better brand IE: Federal HST's or Wincester Ranger T's..

whats the diameter of the brass ?? is it different than your other ammo ??

11-19-2012, 12:55
I just found this link:

This is the exact same problem I'm having.
Also notice in post no 7 that the op mentions the exact same ammo I'm using.
Gotta have something to do with it.

That being said, in the very last post on page two he says it turns out the chamber was not machined properly.

11-19-2012, 13:00
Check the following dimensions of both types of rounds, the ones that fit and the one that has difficulty being removed.

Neck diameter - .473
Rim diameter - .480
Case length - .898

If other brands of ammunition fire through the weapon, extract correctly and can be hand cycled, IMHO it's an ammunition problem.

Other dimensions can be obtained from this drawing.


11-19-2012, 13:10
I've never had a problem with Hornady, but even if you simply switch to another brand I'd still think the larger problem is with your chamber.

Do you see any deformation, nick, dent, or scratch on the bullet noses themselves?

11-19-2012, 15:28
OP, I've never had a problem with those exact rounds in my gen 4 G21, or any .45 I've owned, for that matter. I would think they are probably out of spec. If every other round doesn't give your gun problems, it might be a bad batch from Hornady, which is generally a stellar ammo manufacturer, but no company is immune from the occasional error.

11-19-2012, 16:04
Bring it to Hornady's attention and stop using it.

11-19-2012, 16:07
I would guess that it is the bearing surface of the truncated cone nosed bullet that is coming into contact with the rifling. I had this problem with a lone wolf barrel in 45 and had the freebore area lengthened to accomodate the bullet. Lone Wolf barrels were known for this in 45 and 40.

Obviously I wouldn't want to do anything to an O.E.M. barrel, I think you should contact Hornady first and discuss it with them. If this ammo has worked in the past in Gen 3 Glocks I would also contact Glock and ask them for advice.

11-19-2012, 16:20
I'd like to see if there are any rifling marks on the nose of the bullet when you are able to extract an unfired round.

The ogive profile of a hollow point is much different than ball ammo. A lighter bullet also is a shorter bullet - so when it has a longer oal, its ogive is much further forward. I think the ammo is the culprit and the bullet is going deeper than the leade from the forward end of the chamber to the beginning of the rifling.

Could you compare your two barrels and eyeball if the leade is the same between the two? If so, I think its the ammo.

11-19-2012, 19:10
The only time I've ever experienced this was with a Gold Dot factory load in a CZ 9mm pistol.
The chamber was cut too short & the bullet nose was jamming into the rifling.

GTalker, DO you see marks on the bullet noses that could indicate this is happening?