Glock will most likely send you replacement magazines. They did for me. They sent them to me the day I called them & asked me to send my originals back.

Botach Tachtical http://www.botachtactical.com/gl201010for1.html has them cheap with free shipping, but sold out at the moment.

I would suggest getting 10rd factory mags. If you have 15rd mags blocked to 10rds with the factory 15rd spring, your inducing more pressure on the slide because you have less weight on top of the spring due to the 5 less rounds and more spring pressure. It would work IF there is an insert at the bottom to stop the follower at 10rds, and the spring remains at full length for 15rds. But if they blocked it off at base plate area and raised the bottom of the mag completely up, which raises the spring bottom up more, this would be your issue. At that point, you would have to clip off a single coil and retry using the mag.

I don't think Glock would send me new magazines once they find out they were 15 round magazines blocked to 10 rounds by my FFL.

@Ezveedub,

I'm going to ask my FFL how they blocked the magazines tomorrow.

Disassemble them and see for yourself how they blocked them. If it's just a block, leave it out and try again.

Jim Flynn (on Gunbroker) has 10 round Glock factory mags if you are interested.

I haven't gotten around to ordering any 10 round magazines. Finding them isn't a problem for the G20 as it is for lots of other guns. Been spending my money on things for my other guns.

I can't disassemble the magazines because my FFL permanently pinned them.

Quote from: PandaBear on October 14 2013 08:11:02 PM MDT
I haven't gotten around to ordering any 10 round magazines. Finding them isn't a problem for the G20 as it is for lots of other guns. Been spending my money on things for my other guns.

I can't disassemble the magazines because my FFL permanently pinned them.

That's just stupid. How does he expect his "customers" to properly maintain and service this vital piece of equipment? Unacceptable. BTW, there's no such thing as "permanent" anything anymore (unless you're permanently dead, which substandard equipment may lead to). Pins are just pins. If the floor plate is pinned, they're cheap.  Please post some pics, or send them (the pics or the mags) to me. I'll figure it out.

Add to that, if they've been modified as it seems, Glock won't honor the warranty.

Quote from: Buckeye 50 on September 21 2013 08:32:49 PM MDT
I have put 150 rounds of various brands through my new Glock 20 full size Gen 4 with zero problems (knock on wood).  Love it.  I said I would NEVER have a Glock............ (the check is in the mail, I promise I won't..........)

Love it - make get a 29

Mine has been flawless as well using buffalo bore, underwood, hornady, cor bon, as well as the weakest 40 powered stuff.

I live in the CA where they don't want us to have guns. 10 round limit for all magazines. My FFL did not give me the option of accepting the magazines as parts kits for liability reasons so they pinned them.

I may have caused the FTFeeds by limp wristing. Getting more ammo soon to give it another go.

Here is what is happening with the last round of my magazines. I have a factory 10-round magazine that I am taking to the range tomorrow in hopes that my FTF problems will go away. If not, then I think I will replace the slide lock spring as someone mentioned earlier in the thread.

UW 180 pictured. Also occurs with UW 165. Have not tried any other ammo. Total round count down the pipe is 234.

FTF on last round is almost always a mag spring issue.

If you want I have dozens of g20 10 round glock factory mags for sale or trade.

What happened at the range with the new factory mag?

Took a friend to the range on a busy Sunday and before I could put rounds through my G20, the range officer told us our 2 hour time limit was up. I had the factory 10 round mag loaded up with UW 180 so I fired off all 10 rounds and didn't have a FTF. Looks like the problem is with my 15 round blocked magazines, but I am planning on going back to the range next week to do further testing.

Quote from: gobigorgohome on March 04 2014 10:56:49 PM MST

If you want I have dozens of g20 10 round glock factory mags for sale or trade.

gobigorgohome,

  I have 3 Gen 4 Standard Capacity Magazines, would trade for 10 rounders.  E-mail me at " DE12453@hotmail.com " if you are interested.  They are listed for sale on GunAuction.com but have no bids yet, I can end it early if you are interested in trading.

Thanx,  Dusty

It's interesting you post this, as I've got a similar thread (http://10mm-firearms.com/10mm-semi-auto-handguns/g20-gen4-ftf-issues/) started after yours for the same type of issue (I have 15rd factory mags that I always just load to 10, easier that way).  It will be interesting to see if you're able to solve your problem with new mags/springs.