Author Topic: Question on "unsupported" factory Glock 20 barrels  (Read 439 times)

Kenk

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Question on "unsupported" factory Glock 20 barrels
« on: September 04, 2017, 09:56:25 AM »
Hey Folks,
When using the factory G 20 gen 4 unsupported  barrel for standard to slightly higher hand load pressures, are there many, if any safety issues to be concerned with? My loads are hotter than the factory watered down stuff, but are nothing like my favorite Underwood hunting loads
Thanks in advance

sqlbullet

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Re: Question on "unsupported" factory Glock 20 barrels
« Reply #1 on: September 04, 2017, 10:27:05 AM »
Glock barrels are not "unsupported". And plenty of guys here run Underwood in their Glock factory guns.

Glock barrels are "loose".  The tolerances are a bit more generous than my other guns.  A load that will measure .429 out of my EAA chamber will measure .432 out of my Glock chamber.  And that can be true even of "FBI" loads.

Guys who buy aftermarket barrels do so for different reasons than chamber support most often.  Generally it is to shoot lead bullets.  Again, tolerances are the issue.  My Para barrels slug out to .399", and my EAA a generous .400".  But my Glocks all come in well over .401"  Fastest way to leading is shooting bullets that aren't .001" larger than groove diameter, but for many Glocks that means a bullet sized .403-.404".  First, hard to find unless you cast your own, and even then you have to order a very custom mold, or lee-ment it out a couple .001"'s.  Two, a bullet that far over spec often results in loaded ammo that won't chamber correctly.  And if you force it then you have "clamped" the brass into the bullet asking it to pressure spike on you.  I have had OK luck with bullets between .402 and .403 as they fall from the mold, lubed with felix lube and cast from air cooled wheel weights.  The not rock hard 12-14 BHN bullets can bump up enough to seal the bore and I don't get leading, even with full-power loads.

If you are seeing a serious belly on your brass, a heavier recoil spring is the first place to look.  It likely indicates more that your gun is unlocking early than any serious lack of support.

Kenk

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Re: Question on "unsupported" factory Glock 20 barrels
« Reply #2 on: September 04, 2017, 10:33:19 AM »
Very good, thanks for the informative reply, I really appreciate it

Ken

Kenk

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Re: Question on "unsupported" factory Glock 20 barrels
« Reply #3 on: September 04, 2017, 10:46:36 AM »
So if I do run lead (Brinell 18) at reasonable velocity's in my factory G20 barrel, possible leading issues would be my only real concern, correct?

sqlbullet

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Re: Question on "unsupported" factory Glock 20 barrels
« Reply #4 on: September 04, 2017, 12:04:29 PM »
Glock says no lead.

Some guys with kaboomed guns blame lead in glocks.

I run lead, but worked up slowly and check barrels VERY frequently for leading

Your mileage may vary.  Act accordingly.

I also think 18 may be a little hard, but again, work up slowly, check barrels often.

Kenk

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Re: Question on "unsupported" factory Glock 20 barrels
« Reply #5 on: September 04, 2017, 03:43:31 PM »
Great, Thanks man!

The_Shadow

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Re: Question on "unsupported" factory Glock 20 barrels
« Reply #6 on: September 04, 2017, 04:14:34 PM »
The gen 4 Glocks don't have the assorted spring systems that the gen 3 and earlier does.

One thing I do with my Glock 3rd gen guns is run a non captive recoil spring setup from Wolff Gun Springs, here is what and why;
I feel that the extra pressure the non captive springs apply at lock up makes a difference with the higher impulse ammo like Underwood and others including my own...  In my factory barrels case head expansion at 0.4340" is where you will see the brass expand beyond the chamber size and smile...


Glock 20Sf Factory spring test
It takes 5lb 3oz to start the slide to move from the locked position
Full retraction at 18lb 0oz at lock open

Glock 20SF spring test Wolff Gun Springs 22lb RSA installed
It takes 6lb 4oz to start the slide to move from the locked position
Full retraction at 22lb 9oz at lock open

22-Slightly over a pound difference 1lb 1oz to start the slide to move from the locked position
24-Slightly over a two pound difference 2lb 3oz to start the slide to move from the locked position
22-Slightly over a 2 pound difference 2lb 9oz at lock open
24-Slightly over a 6 pound difference 6lb 1oz at lock open
« Last Edit: September 04, 2017, 04:19:16 PM by The_Shadow »
The "10mm" I'm Packin', Has The Bullets Wackin', Smakin' & The Slide is Rackin' & Jackin'!
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Kenk

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Re: Question on "unsupported" factory Glock 20 barrels
« Reply #7 on: September 04, 2017, 04:44:37 PM »
Hi, so for the gen 4 G20, what would you recommend in a 22 Lb setup, a link to the manafacture's site would be very helpful
Thanks for everyone's help

Ken

The_Shadow

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Re: Question on "unsupported" factory Glock 20 barrels
« Reply #8 on: September 04, 2017, 05:55:43 PM »
I am not as familiar with the Gen 4 availability for RSA's, although some have used some with the 22lb springs successfully.
The factory was said to be doing a fair job with most ammo.
The slide of the gen 4 has a larger hole where the spring assembly sits.
You might want to look at this site and call and inquire about the 4th gen options for you pistol if they are available
https://www.gunsprings.com/GLOCK%20%C2%AE/cID1/mID5/dID116
The "10mm" I'm Packin', Has The Bullets Wackin', Smakin' & The Slide is Rackin' & Jackin'!
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Kenk

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Re: Question on "unsupported" factory Glock 20 barrels
« Reply #9 on: September 05, 2017, 12:03:17 AM »
Thanks


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Ridgerunner665

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Re: Question on "unsupported" factory Glock 20 barrels
« Reply #10 on: September 05, 2017, 05:11:36 AM »
The best option for Gen 4 springs is NDZ Performance...

I did a lot of reading before getting mine... They have a website where you can order their rods and springs... But they offer more options on preassembled RSA's on eBay.

I put their 20 pound spring and rod in my G40.

Shipping was quick, parts are perfect.

Kenk

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Re: Question on "unsupported" factory Glock 20 barrels
« Reply #11 on: September 05, 2017, 06:14:58 AM »
Thanks, are you able to get the entire spring/ rod set up all in one?

Superzuki

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Re: Question on "unsupported" factory Glock 20 barrels
« Reply #12 on: September 05, 2017, 06:31:06 AM »
Hi, so for the gen 4 G20, what would you recommend in a 22 Lb setup, a link to the manafacture's site would be very helpful
Thanks for everyone's help

Ken

I have a G20/3 and a G21/4. I put a Wolff non-captured recoil assembly in the G20 and a Lone Wolf captured assembly in the G21. 

That said: Lone Wolf sells an adapter to fit a Gen 3 style RSA in the Gen 4 slide. It goes on top of the spring, and is secured by the screw, and fits it to the larger opening in the slide.
I have used 20lb springs for Underwood and lesser powered rounds. the 22lb spring works with Underwood and hot handloads, but is too stiff for 'standard'  rounds in my pistol.

The G21 has 20 and 24 pound springs for 45 Underwood +p and 40 Super shooting.  With the adapter it works flawlessly, shoots great.     

Kenk

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Re: Question on "unsupported" factory Glock 20 barrels
« Reply #13 on: September 05, 2017, 07:35:07 AM »
Thank you!

Ridgerunner665

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Re: Question on "unsupported" factory Glock 20 barrels
« Reply #14 on: September 05, 2017, 07:50:21 AM »
Thanks, are you able to get the entire spring/ rod set up all in one?
Yes, from eBay.