G21 stock recoil spring design fault?


November 1, 2007, 10:56 PM
I've had a G21SF for a couple of months. I haven't fired it much. So far, no malf's in nearly 200 rounds of UMC. But in dry-fiiring it, I have noticed something less than "perfection." On a few occasions, now, I have noticed a gritty feel when cycling the slide, and the pressure felt more than normal. First time I noticed it, I thought it just needed to be broken in a bit. It eventually went away, and I forgot about it. Then it happened again. And, again, it went away, and I forgot about it. Now the third time it happened, I really examined it. Pulling the slide back, it felt like the recoil spring was rubbing against the frame, somewhere. I carefully field stripped, and the recoil spring seems like it was off its "perch," on the front of the barrel lug. But then again, everytime (EDIT: Most of the time.. But when stripped very slowly and avoiding jarring, it is still on the top perch, but just barely hanging on). Replacing it and reassembling the gun, the problem went away. I can't "reproduce" the problem on demand, but I am pretty sure that the recoil spring guide rod is occasionally slipping down, which puts the rear part of the spring in contact with the bottom of the frame. Cycling the slide then causes the spring to bunch up and skid. I am fairly certain that it wouldn't cause a malfunction, but it is rather annoying.

I wish I could check on GlockTalk.com, but I can't register, because there's a problem with my popup blocker, methinks. Anyone else experience this? Is this something that the factory can fix? Or is it a design flaw? Any recommendations on a drop-in aftermarket CAPTURED guide rod/spring that will fix this?

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November 1, 2007, 10:59 PM
sounds normal. the recoil spring moves into a diifferent "notch" after reassembly.
i would call GLOCK 770 432 1202

November 1, 2007, 11:06 PM
Yeah, ok. But very infrequently, I get that grinding/skidding thing happen which doesn't feel normal. And I don't know that the guide rod actually transfers to a different notch. I mean, I see that lower notch, but when I disassemble very carefully, the guide rod is still on the upper notch, but just barely hanging on by the edge. I am pretty sure that if is transferred to the lower notch, there's not way it could get itself back up the the higher notch on its own.

November 1, 2007, 11:12 PM
I stand corrected. I can just manage to reassemble the pistol with the guide rod in the lower notch if I dislodge it with the slide partly reassembled. The rubbing/grinding thing does NOT happen. So I guess I'm stumped, for now. But when it DOES happen, it sure feels like the spring is binding on something.

EDIT: And then again, I notice that if I reassemble it on the top notch, even if I cycle and drop the slide full force, then carefully disassemble, the rod stays just barely on the top perch. Curious. I wonder if the gun is less reliable, somehow, when the guide rod does not drop down to the lower perch... if that's indeed what it's supposed to do. Come to think of it... when its there hanging on the edge, the force of the spring kinda bends the guide rod a bit, which might cause it to hang up there. I think from now on, I'll drop the rod while assembling, and see if that helps.

EDIT ???: OK, now I'm really stumped. After dropping the rod to the lower notch, racking a few times, then carefully disassembling, the darn rod is right back to the lip of the upper notch! Now, how does that happen? :) Oh, well.. I think I'll forget about it. As long as it works, right? I guess it might be rubbing on the guide rod, itself.... but how it gets that way and stays that way for many slide cycles, I guess I'll just have to keep wondering... until I buy a metal guide rod.

November 1, 2007, 11:58 PM
200 rounds and some dry fire? Are you kidding? :rolleyes:

Put at least 2000-rounds and some dry fire through it, and we'll talk! :D

The guide rod jumping to the center position from the half moon thingy is normal. :)

Ever change oil from a brand new engine, and look at it carefully? You'll see little flakes of metal! :uhoh:

Your G21 is an engine of sorts, and parts need to wear in--in particular the slide rails. :scrutiny:

Now, go shoot that awesome .45 and have fun! ;)


November 2, 2007, 03:06 AM
The spring guide rod also rests against the takedown switch. When you pull down on the switch, it pulls down on the guide rod. Mystery solved.

November 2, 2007, 01:49 PM
The rear of the recoil spring assembly must be positioned fully 'up' (toward the barrel) in the semicircular notch located on the front of the barrel lug during reassembly. This positions the rear of the recoil spring assembly so it can be properly located in the frame during reassembly.

When you field-strip the pistol the rear of the spring assembly is sitting 'low' in the notch, which is normal. This captures the assembly for field-stripping.

When the pistol is reassembled, however, the rear of the spring assembly must be positioned completely 'up' in the small notch ... NOT in the same 'low' position in which you found it during field-stripping.

When I attended my Glock armorer class we were warned that if someone didn't position the rear of the spring assembly completely up into the semicircular notch for reassembly that the assembly could become damaged/broken. It puts unintended, improper stress on the base of the plastic guide rod, and it could become damaged. In the single spring assemblies this can result in the rear base of the guide rod breaking off. In the subcompact dual-spring assemblies, with metal bases, the inside of the frame can become marred, scratched, gouged, etc., if the metal base of the guide rod is sitting too low in the barrel's notch during reassembly.

Sure enough, one day one of the guys had his guide rod come out the front of his G22 after he reassembled it and was hand-cycling it. The base of the rod had broken off. After I replaced the spring assembly and was talking to him, I learned that he had never bothered to properly position the rear of the assembly completely up in the barrel lug notch during reassembly. Didn't think it was important. :banghead:

Also, it's not uncommon for the bottom of the barrel to rub against the top of the recoil spring, at the rear of the spring assembly, during barrel movement (unlocking/locking). It can sometimes sound like a scrunchy, unlubricated screen door, and you can probably see a rub mark along the bottom of the barrel at some point after a while. Rubbing lubricant along the bottom of the barrel in this area, while you're lubricating the pistol after cleaning, can help reduce the friction in this area.

Of course, remember that the pistol was intended to cycle during shooting (aside from initially loading the chamber in preparation to fire) when things happen very fast, and the spring was designed for this task. Trying to duplicate the 'feel' of the functioning intended to occur at 'full speed', via hand-cycling, isn't going to yield the same results, you know. Recoil operated is not the same as 'hand operated'. ;) Also, I rather doubt they designed the firearms so owners/users could sit around and slowly hand-cycle the empty pistols, listening to them ...

Read the entire owner's manual. It's never a bad idea.

As an armorer I've had to resolve more functioning problems caused by insufficient or excessive lubricant than I have actual parts problems. Either extreme can have its own problems. I've never understood why some folks just seem to think that when they have a firearm and a bottle of lubricant in front of them that they're somehow inherently 'gifted' with the knowledge of how to properly lubricate the firearm. I've watched some folks very deliberately apply barely a 'fly speck' of lubricant to a gun, and then another person try to use half the bottle of oil, saturating the gun (so they don't have to worry about oiling it for the next several months :eek: ).

If you have a Glock armorer in your area, like perhaps wherever it was that you purchased the pistol, why not stop by and talk to him/her for a few minutes to learn more about your new pistol, how it functions, how it should be maintained, etc..

It pays to learn about the needs of each design and the recommendations of each manufacturer.

You can also call Glock if you want to talk to a customer service person, or maybe a technician, depending on how busy they may be at the time.

Just my thoughts.

November 3, 2007, 06:07 PM
Ryan: "The spring guide rod also rests against the takedown switch. When you pull down on the switch, it pulls down on the guide rod. Mystery solved."

Indeed. Thx for the explanation. I now see the ingenuity of the design. What an amazing way to get an easily interchangeable captive spring in and out of the gun and yet give it a good purchase point.

November 3, 2007, 11:12 PM
So is my gun not normal? Whether I assemble it up towards the barrel, or down away from the barrel, it automatically goes back to the up position, next to the barrel as soon as the slide goes back about a quarter inch. And it stays on the upper notch towards the barrel when I disassemble it.

When the pistol is being disassembled for cleaning the rear of the guide rod does indeed remain in the upper half-moon notch of the barrel lug. It'll be just a bit lower than the maximum 'upward' spot of the half-moon notch, though. Normal.

It's just that it's recommended that the rear of the guide rod is pushed 'higher' (fully) up into the half-moon notch for reassembly than it's found when the pistol is field-stripped (and the rear of the rod is sitting a bit lower against the half-moon cut in the front of the lug).

The armorer's manual just states to be sure that the rear of the recoil spring tube rests in the half-moon cut in the bottom of the barrel lug.

When the armorer instructor was explaining it he didn't make a big deal of it, but he did take the time to reinforce to us that if the rod isn't fully up in the notch for reassembly that the rear of the rod could be stressed and potentially damaged. Once the rear of the rod has shifted to its normal position in the frame (after reassembly) it doesn't depend on the barrel lug for functioning. The next time the pistol is field-stripped, though, the barrel lug will catch and retain the rear of the recoil spring/rod assembly, holding it in place until the user can remove it.

The bottom edge of the lug's lower angle (below and behind the bottom of the half-moon cut) is used engage the rear hooked edge of the top of the slide lock.

If you look at the design of the slide lock, you'll see that it moves back and away from the rear of the guide rod assembly when it's pulled downward for disassembly ... and when it's bouncing down & up during the recoil cycle for each shot fired.

This design is a fairly common method of capturing the guide rod for disassembly in many modern pistols. However, the size and shape of the notch used to catch the rear of the guide rod can vary among the designs, too. In the traditional metal-framed S&W pistols, for example, the notch is little more than a 'finger nail nick', so to speak. Since that design uses a non-captive rod & recoil spring, it's not uncommon to see spring tensioned guide rods fly off barrels if the owner/user isn't careful during disassembly/reassembly and the rod's base slips free of the minimal notch. I've often thought that safety glasses should be used when teaching new users how to disassemble & reassemble their new issued S&W pistols. ;)

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