Glock 20 Gen 4 failure to feed Underwood 180 TMJ

[G20g4]

I have a Glock 20 gen 4 and this is my first Glock. I absolutely love the gun it handles great, however as soon as I wanted to shoot real 10mm ammo I had multiple jambs. I had minor work done to the gun, lighter trigger pull, night sights, and slide release done by Glockmeister, who told me the std double spring should handle all ammo hot or light. Any one had this problem? Or found the cure?

[Geeman]

You need to figure out what's happening.

First, make sure your wrists are solid.  Make the recoil move your whole forearm, not just snap your wrist.

My guess it the slide moves so fast that it rebounds back under spring pressure so the next round isn't in position in the magazine yet.  There will be marks in the mis-fed case where the slide has impacted the side of the case because it wasn't in position to push it from behind.  Solution is a stronger recoil spring (slow down the slide), stronger magazine spring, or both.

Greg

[4949shooter]

Yes..


Underwood 180 TMJ did not run well in my Gen 3 G20. The Underwood 165 TMJ runs great. Try a different ammo, maybe start with some CCI Blazer or Federal 180 first, or even some Hornady. My suggestion would be to see how your gun runs with the lighter ammo, than try the Underwood in 165.

Good luck!

Edit: I was typing while Geeman was typing. He is probably correct, but I would try some different ammo first to narrow it down.

[Geeman]

Edit: I was typing while Geeman was typing. He is probably correct, but I would try some different ammo first to narrow it down.

And finding ammo that both your gun and you like is very important, likely the most important.  If you plan on using it for self defense, misfeeds need to be super rare. 

Your advise is sound!!!

Greg

[4949shooter]

Let's see what happens!

My G20 needed a 22 pound RSA to fire Underwood. I don't know if they make the heavy weight RSA's yet for the Gen 4?

[Geeman]

Let's see what happens!

My G20 needed a 22 pound RSA to fire Underwood. I don't know if they make the heavy weight RSA's yet for the Gen 4?

There is a bushing (adapter) to add to a steel lone wolf gen 3 guide rod, so gen3 springs will work.  I have a 22# in a Gen4, but should have gone straight to a 24# for the hot stuff.

Springs loose tension.  The stock Gen4 needs to be replaced regularly according to Glock.  Magazine springs go weak too, especially when you keep the magazines full all the time. 

There is a RSA test to do.  Clear the chamber, Drop the mag, dry fire, and while holding the trigger back, point the gun straight up and pull the slide back and slowly let it return.  The gun should lock by spring pressure alone.  Keep the trigger pulled back during the whole operation.  If it doesn't, the stock RSA needs to be replaced.

Greg

[4949shooter]

Let's see what happens!

My G20 needed a 22 pound RSA to fire Underwood. I don't know if they make the heavy weight RSA's yet for the Gen 4?

There is a bushing (adapter) to add to a steel lone wolf gen 3 guide rod, so gen3 springs will work.  I have a 22# in a Gen4, but should have gone straight to a 24# for the hot stuff.

Greg

Ahh yes....I had forgotten about those.

[tommac919]

snip
Springs loose tension.  The stock Gen4 needs to be replaced regularly according to Glock.  Magazine springs go weak too, especially when you keep the magazines full all the time. 
snip

I can understand a spring being replaced due to use...
But if I remember right a spring will not get weakened by being compressed all the time.
It is the compression and expanding that causes springs to weaken over time.

[Intercooler]

  Is it just me or does this seem like a common problem?

[Geeman]

  Is it just me or does this seem like a common problem?

Is there a semi-auto anything that digests everything without a hickup?

Greg

[Intercooler]

Lots of them really.

[Rich10]

  Is it just me or does this seem like a common problem?

Is there a semi-auto anything that digests everything without a hickup?

Greg

Lots of them really.

But in 10mm?  I don't know??  My only 10mm is a Gen3 G20SF.  I only ran about 500, maybe a few more than that, before I installed the longslide setup.  I've not had a problem with it set up either way. 
But I do read about issues with Glocks and the 10mm.  I also read about issues with every other possible pistol and 10mm.  What is the one common denominator? The 10mm is, and guys tinkering with their guns and screwing them up.....

[fanninland]

These pics show what happened when I tried Underwood 180gr TMJ in my stock G20 gen4 other day...shot maybe 10 rounds and over half had malfunctions.

However, Underwood 200gr TMJ did much better - shot 50 rds with one failure to extract.

Have not experienced any problems with Double Tap 200gr wfngc hardcast, but have only shot 10 or so as they're so pricey.  The lower power stuff (PPU, Armscor) feeds fine.

I'm thinking of trying an aftermarket gen4 RSA but for the life of me can't find the thread I saw last month with that info. Seems there were 2 companies now making gen4 rsa's - anyone know who?



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[G20g4]

Thank you for the info. I ordered a new spring assembly for my Gen 4. I actually found a link on this forum and spoke with the owner today, the website is www.spinco.com and I ordered from them after I explained I bought a 10mm and want to shoot 10mm ammo not .40.  You need to call them so they know you are shooting full power stuff. I will see how this does and report back.
Thank you for the advice,
Darrin

The other website was www.dpmstemsusa.com

[G20g4]

Thank you for the info. I ordered a new spring assembly for my Gen 4. I actually found a link on this forum and spoke with the owner today, the website is www.spinco.com and I ordered from them after I explained I bought a 10mm and want to shoot 10mm ammo not .40.  You need to call them so they know you are shooting full power stuff. I will see how this does and report back.
Thank you for the advice,
Darrin

The other website was www.dpmstemsusa.com