Blog on 9mm short chamber bullets.

[O4L]

I didn't know that there are pistols, including some Glocks, that have shorter chamber's.

http://blog.westernpowders.com/2020...ues-with-the-sns-casting-125-grain-roundnose/

 

[Shadowrider]

The Gen 5 9mm Glocks have chambers so short they won't even chamber some defensive factory rounds. Actually they will chamber when the bullets gets seated deeper when it slams into the leade. They are built robust enough that most folks don't even know it's an issue, but it's not optimal and it's damn sure not "PERFECTION" either. Don't think any of the prior generations had an issue with this.

 

[O4L]

The Gen 5 9mm Glocks have chambers so short they won't even chamber some defensive factory rounds. Actually they will chamber when the bullets gets seated deeper when it slams into the leade. They are built robust enough that most folks don't even know it's an issue, but it's not optimal and it's damn sure not "PERFECTION" either. Don't think any of the prior generations had an issue with this.

I read a lot of info about guns in general and I had never heard of this. The article I linked to has a theory as to why this is a thing.

 

[thor447]

The plunk test will never lead you astray!

 

[O4L]

The plunk test will never lead you astray!

Right? I just never considered that you need to put factory ammo through the "sit and spin" test.

I will be plunk testing my factory SD ammo this evening.

 

[Shadowrider]

I read a lot of info about guns in general and I had never heard of this. The article I linked to has a theory as to why this is a thing.

You and millions of other folks. I have several H&K pistols and my SIL has a couple of Walthers. H&K and Walther aren't exactly known for sloppy chambers if you get my drift. They actually use the European standard stepped 9mm chamber and that's probably why they get the accuracy they do. Even those will plunk and spin every factory hollow point I've tried in them. My G17 won't and that's why it's a range blaster only gun for me.

 

[O4L]

You and millions of other folks. I have several H&K pistols and my SIL has a couple of Walthers. H&K and Walther aren't exactly known for sloppy chambers if you get my drift. They actually use the European standard stepped 9mm chamber and that's probably why they get the accuracy they do. Even those will plunk and spin every factory hollow point I've tried in them. My G17 won't and that's why it's a range blaster only gun for me.

I think I only have three or four different brands of HP 9mm. I will check them all and report back. I have a G48 so I don't know if it is one of the short chamber models.

Which HP ammo has not passed the test in your G17?

 

[Mad Professor]

I didn't know that there are pistols, including some Glocks, that have shorter chamber's.

http://blog.westernpowders.com/2020...ues-with-the-sns-casting-125-grain-roundnose/

The Gen 5 9mm Glocks have chambers so short they won't even chamber some defensive factory rounds. Actually they will chamber when the bullets gets seated deeper when it slams into the leade. They are built robust enough that most folks don't even know it's an issue, but it's not optimal and it's damn sure not "PERFECTION" either. Don't think any of the prior generations had an issue with this.

The only Glocks I seen it with Gen 5 9mm. The only defensive rounds I have personally seen with issues have been 147g and I don’t remember the brand. I have tested about 10 of my Gen 5s with 147g HST and Lawman and none of them hit the lands. I have seen it more at matches with all kinds of reloads. Almost always, the symptom is the shooter cannot clear the gun at the end of the stage. The bullet is stuck in the lands preventing the barrel from unlocking and allowing the slide to move back.

Bullets with a larger ogive toward the tip (and/or loaded longer) are the usual culprit. Heavier bullets are usually that way and a hollow point version will generally do that.

CZs are far worse and it has been a known issue for many years. It shows up in even in some 115g loads.

The throat is lengthened slightly with a throating reamer to stop it. I have cut them just past the point of the load engaging the lands.

The reamer to do this is custom built out of carbide and expensive. High speed steel won’t get it on the CZs. I’m not sure on the Glocks, as I’ve only done one.


So far, the only gun of mine I have had to cut was a CZ Shadow 2.

 

[Mad Professor]

Just to be clear on nomenclature I'm using here whether correct or not.

You don't want to lengthen the chamber you only want to work on the throat. There is a big difference between a chamber reamer and throating reamer.


There is some good info here. Attached image is from this thread.
https://forums.brianenos.com/topic/268657-reaming-shadow-barrel/

 

[Shadowrider]

I think I only have three or four different brands of HP 9mm. I will check them all and report back. I have a G48 so I don't know if it is one of the short chamber models.

Which HP ammo has not passed the test in your G17?

I think it was 127 grain Winchester Ranger T, IIRC...

EDIT: Curiosity got the best of me and I had to try to find out so I just checked.

147 HST = Clears
124 Gold Dot = Clears
127 SXT (older Ranger T lot with black oxide coating) = Clears

So it would have to have been some Hornady XTP loads that I had once upon a time. I also remember having this conversation with @Mad Professor and having to reseat some of my reloads which mimics the XTP/HAP profile somewhat a full .040" deeper to get them to work. That's a full 1 millimeter different than my G19 or G34 was and both earlier than Gen 5. The Gen 5 9mm chamber is definitely different.