short chambers in Glock gen 5?

[thehudge]

I was told today that the Gen 5 barrel chambers are short, not allowing for proper seating with (longer) 147gr bullets.

I loaded a few dummy rounds (the shortest OAL 1.100) up with 147gr TC and it felt as if the bullet was contacting the rifling. Meaning, It wasn't stuck but pulling the slide back was a chore with a distinct bump to get it back/going.   

This is first I heard of it. 

[jmtyndall]

Take the barrel out of your slide. Drop the loaded round into the barrel and the round should fall all the way into the chamber making a distinct "plunk" sound. Put your finger on the back of the round and spin it. If it doesn't plunk or doesn't spin you need to go shorter because the bullet is touching the rifling (or your round is out of spec in some other dimension). 

 

Racking rounds in and out of your gun isn't going to tell you much. Too many mechanical interactions for you to know what's going on in the chamber.

 

A round that's hard to eject from the gun is more likely brass that's too big at the base unless you see rifling marks on the bullet.

[hamiltonian]

 

2 hours ago, thehudge said:

I was told today that the Gen 5 barrel chambers are short, not allowing for proper seating with (longer) 147gr bullets.

I loaded a few dummy rounds (the shortest OAL 1.100) up with 147gr TC and it felt as if the bullet was contacting the rifling. Meaning, It wasn't stuck but pulling the slide back was a chore with a distinct bump to get it back/going.   

This is first I heard of it. 

My brother got a Gen 5 and said the same thing.  The rifling is very close to the chamber.  I have had all my Glock barrels free bored so that I don't have to worry about over all length.  If it fits in the Glock mag, it will chamber in my guns.

[MemphisMechanic]

Some bullet profiles are much more friendly than others.

 

You can probably get virtually all FMJs to 1.120+ in most gen5 barrels. Acme 124s and Blue Bullets 135 / 147 tend to let you load a pinch longer than most in coated. Everglades 124s definitely do.

 

I’ve reamed a few Gen5 Glock barrels for guys who want to use a fat-round-nosed 147 out past 1.120 - to 1.150 or so, like they’re used to doing with their other guns.

 

Edited April 24, 2019 by MemphisMechanic

[thehudge]

It does not pass the plunk test, even with the one loaded to 1.100 but my 115 round nose with an OAL of 1.135 plunk fine.  I guess bullet design has something to do with it as well.  

So I guess its ether a new barrel or different bullets.   

[nick779]

Ill be having my hand at this in the next few days. Should be picking up a gen 5 34 today, ill do some testing with the reloads I have and report back. I might have to hit up MM for a barrel reaming service depending on how this goes.

 

Ill be testing:

124gr TMJ Speer Lawman

124gr FMJ Fenix 130PF Reloads

147gr FMJ Fenix 130PF Reloads

[MemphisMechanic]

@nick779 those will pretty much certainly all pass. FMJs can be loaded substantially longer than coated due to a combination of shoulder profile (ogive) and diameter (they’re .001” smaller in most cases.)

[MemphisMechanic]

7 hours ago, thehudge said:

I guess bullet design has something to do with it as well. 

 

It’s called the bullet’s ogive. It’s well documented and understood if you aren’t a novice reloader.

 

The tip of the bullet isn’t your problem; that is sitting in the center of an empty hole. The shoulder (ogive) of the bullet is what runs into the rifling. A very pointy bullet profile has it’s ogive further back, whereas most coated 147s are pretty fat in profile and will run into rifling much earlier.

 

This should help:

 

 

 

Edited April 24, 2019 by MemphisMechanic

[nick779]

1 minute ago, MemphisMechanic said:

@nick779 those will pretty much certainly all pass. FMJs can be loaded substantially longer than coated due to a combination of shoulder profile (ogive) and diameter (they’re .001” smaller in most cases.)

 

Thats what im hoping for. I dont reload, so blue bullets or other coated bullets are off the table.

 

Edit: I saved that sheet from the last time you posted it. Its a great way to help explain why you plunk test.

Edited April 24, 2019 by nick779

[thehudge]

I'm using 147 FMJ Truncated Cone. The ogive is what is contacting the rifling.    

[Stymie12000]

The gen 5 definitely has a short throat.  I ended up picking up a KKM barrel so I can load to my satisfaction.  I have access to throat reamer but wasn't sure if the surface treatment on the barrel would be hard on the reamer.

 

I can load long with the KKM. And accuracy is slightly better!

[ironpony]

Same findings here. Precision Delta and Montana Gold 124 gr. FMJs are now loaded to 1.100 oal for my gen 5s.

I’m curious if that small amount of extra rifling increases accuracy, if so why not make the barrel .100” longer.
No need to answer that. Oh, my LGS is having the Glock rep out for a sale day and I may question him just for the heck of it.

[thehudge]

KKM barrel is on its way. 

 

Thanks a lot, again. 

[12glocks]

27 minutes ago, thehudge said:

KKM barrel is on its way. 

 

Thanks a lot, again. 

Is there more freebore on the KKM barrel?

 

Your present situation is one of the reasons I don't like coated rounds.  I like 147's and don't want to load them really short, doesn't seem like best practice.  If you buy say, 2000 Precision Delta 124 JHP for 8.4 cents per round delivered, your problem will be fixed as well.  This is my personal choice of course and I am not trying to start a debate about the issue.

[AHI]

Is there more freebore on the KKM barrel?

 

The one I have you could load 147 SNS RN  longer than  will fit in magazine.

[MemphisMechanic]

On 4/25/2019 at 7:06 AM, Stymie12000 said:

I have access to throat reamer but wasn't sure if the surface treatment on the barrel would be hard on the reamer.

 

A reamer like the Clymer you can buy through Brownells won’t work.

 

(1) Shadow 2, XD, M&P, Walther, Glock, and others all harden their barrels. The barrel is harder than highspeed steel (HSS)... which is what thread taps, and that reamer, are made from. You’ll wear the reamer down on the barrel you’re attempting to cut. These barrels require a much more expensive carbide tool.

 

(2) But that doesn’t matter, because it won’t fit anyway. A polygonally rifled barrel requires the pilot of the reamer (the smooth tip) to be .001” smaller than conventional rifling. So it doesn’t fit into the barrel in the first place.

 

I have a reamer that will cut a G5 barrel. I had it made through @1911luvr who works with a tool & die maker. They’re not cheap.

 

...And then I had to take a diamond lap to the pilot in order to get his to fit my Walther barrels. My PPQs and Q5s all eat anything you can stuff into the mags now. I have cut a few 5th Gen Glock and Shadow2 barrels for friends, too.  

 

Edited April 26, 2019 by MemphisMechanic

[Stymie12000]

1 minute ago, MemphisMechanic said:

 

A reamer like the Clymer you can buy through Brownells won’t work.

 

(1) The barrel is harder than highspeed steel (HSS)... which is what thread taps, and that reamer, are made from. You’ll wear the reamer down on the barrel you’re attempting to cut.

 

(2) But that doesn’t matter, because it won’t fit anyway. A polygonally rifled barrel requires the pilot of the reamer (the smooth tip) to be .001” smaller than conventional rifling. So it doesn’t fit into the barrel in the first place.

 

I have a reamer that will cut a G5 barrel. I had it made through @1911luvr who works with a tool & die maker. They’re not cheap.

 

And then I had to take a diamond lap to the pilot in order to get his to fit my Walther barrels. My PPQs and Q5s all eat anything you can stuff into the mags now. I have cut a few 5th Gen Glock barrels for friends, too.  

Yep all makes sense! 

 

I didn't even try with our reamer knowing it is hss. Gave me an excuse to buy a KKM. 

 

Good to know you have a solution for people who want to keep the factory barrel. Too bad glock did this with the gen 5! 

[thehudge]

Loading 147gr FMJ over 3.3gr of Tightgroup at 1.140 oal for an average velocity of 864fps and a 127pf. 

This is out of my sig P320rx.  The kkm barrel has shipped for the G34 gen5 and should be here next week. 

[ironpony]

Is it best to deal with KKM directly or a favorite online site?

[thehudge]

I called them and spoke to a very helpful individual.

[ODP1911]

I've been using the loads I shot out of my gen 4 for my gen 5s and havent experienced any issues. About 1.135" bayou bullet 147 fp.

[OptimiStick]

I have read that early run Gen 5s are worse than later run Gen 5s.  I have an early run gen5 G45 that won’t fit any of my common 147gr reloads - even my short ones for my shadow 2 and PM9.  This is with flat point, truncated cone , round nose from a variety of bullet manufactures - Acme, Precision delta , Montana Gold, DG. Even my Blues 135gr truncated cones which are usually very forgiving. Like you, KKM is on the way.  KKM in my G34 has a much more forgiving freebore. I can load most profiles out to 1.1625 and still plunk and spin 

[nick779]

Took forever, but I finally got to test the Fenix stuff. No chambering issues at all, no plunk test issues. Eats 124gr all day.

 

The 147gr malfunctioned constantly though. Stovepipes and FTF galore. I was running a 15# ISMI with a 4.5# Striker spring, I have a 13# so im going to try that next chance I get. 

Edited May 6, 2019 by nick779

[ironpony]

Now I’m curious as to why aftermarket “Match” barrels have the deeper chambers and are possibly more accurate than Glocks shallow match?

[nick779]

55 minutes ago, ironpony said:

Now I’m curious as to why aftermarket “Match” barrels have the deeper chambers and are possibly more accurate than Glocks shallow match?

 

Probably to allow for more flexible load development, ive also heard that KKMs lock up much more solidly that factory gen 5 barrels.