Gunsmithing Glock 21 SF Trigger Slap/Problem

[Infinity]

I may have a case of the vaginitis and this may belong in a different section of the forum, but please help if you can:

I have a Glock 21 SF that slaps my trigger finger each time I shoot it (as the trigger resets before the next shot). I owned a Glock 19 that never use to hit my finger this way. I can handle it if that is just the way it is but I think there might be something wrong with it, as this is the only gun I own that punishes my trigger finger like this. I prefer to not wear gloves, etc. I'm happy to call Glock but I figure you gents may be able to save me some time without my weapon. Thoughts?

Thanks,
Adam

 

[Infinity]

Anyone able to point me in the right direction? Thanks,
Adam

 

[FedCop]

The 10 mm is a pretty punishing round and the glock trigger destroys the pad of my trigger finger after 50 rounds or so. My 10mm glock did the same to my finger, my 23 with HP rounds does it and my glock 19 eventually does it if I shoot enough. Is it a gen 4? Maybe try going up or down in Grip size to see if that helps.

 

[Infinity]

FC,
Thank you very much for the contribution. I'm not sure I see how that would help but it is worth a try. Thanks again,
Adam

 

[DLew]

I've got a gen3 21sf and haven't noticed this issue personally or with any other glocks I've shot. With the gun unloaded and cocked if you pull the trigger to the rear and hold it back and then cycle the slide and slowly let the trigger out to the reset point, do you feal anything more then just a click? Is it a brand new gun with only a few rounds through it? May want to have an RO or someone at the range shoot it and see if they have similar thoughts.

 

[Infinity]

DLew,
Thank you for getting in here. With the gun unloaded, I tried what you said. I only felt a slight click and the trigger didn't reset until I released the trigger, which is different than when I fire live rounds. When shooting, the trigger force-resets (when I feel the trigger slap). I noticed the trigger safety seems to protrude from the trigger more than my G19 use to. This is a new gun, but not that new. I have somewhere around 300 rounds through it. I'll take it to a local shop and see what they have to say. Anyone who reads this, please take a rip at this. Thanks,
Adam

 

[DLew]

Ok well based on that, do the same thing again, fire trigger, hold to rear, fully pull slide to the rear and sling shot it forward holding the trigger to the rear. The recoil spring should have the same forward momentum on the slide by doing this as it will when firing a live round. Do you feel it yanking your trigger forward or anything odd like its snagging? The only thing it should do is re cock the gun. If you're still experiencing the symptoms take the slide off and see if you see any odd wear signs. Its hard to share what you're feeling and then diagnose online. You'll get it figured out.

 

[Infinity]

DLew,
No dice there, seemed like a logical step though. On your G21sf, how far does the trigger safety protrude forward of the trigger? I'm wondering if perhaps the recoil impulse is transferring through the trigger safety and maybe I'm just noticing it more because of a "sharp" safety. Just a thought. What do you think? Thanks,
Adam

 

[17874]

I may have a case of the vaginitis and this may belong in a different section of the forum, but please help if you can:

I have a Glock 21 SF that slaps my trigger finger each time I shoot it (as the trigger resets before the next shot). I owned a Glock 19 that never use to hit my finger this way. I can handle it if that is just the way it is but I think there might be something wrong with it, as this is the only gun I own that punishes my trigger finger like this. I prefer to not wear gloves, etc. I'm happy to call Glock but I figure you gents may be able to save me some time without my weapon. Thoughts?

Thanks,
Adam

When you say trigger slap, what exactly do you mean? Is the trigger guard hitting your trigger finger under recoil or is the trigger wearing on your finger?

 

[Infinity]

17874, sorry to just get to this now. No, the trigger guard is not hitting my finger under recoil and I'm not sure it is accurate to say the trigger is wearing on my finger although that isn't all the way off. A little perspective. I had a G19 I could shoot for days and never had the trigger wear on my finger. The only place I would feel the "recoil" was through the slide cycling. When I shoot this G21SF Gen. 4, each time I squeeze the trigger, I get this stinging on my trigger finger from the recoil impulse (specifically from the trigger safety protrusion). It doesn't do it when I manually cycle the action (controlled and racked). I've never experienced anything like this. I'm going to go to the shop tomorrow (I think) and see what they think shooting it. Thoughts?

 

[elephantrider]

17874, When I shoot this G21SF Gen. 4

That might be the source of your problem right there. I have Gen3 17s,34s, 26s, and 21s, and have never experienced any sort of trigger slap. I've never heard of that from any Gen3s or Gen4s for that matter. I would contact the Glock warranty department since it is a relatively new gun. You shouldn't have to pay out of pocket to fix a new gun. I wouldn't let you local shop fool with it, unless they are a Glock certafied armorer.

 

[Infinity]

ER, thanks. Yeah, I've been putting it off but something isn't right. Will update once I've gotten some resolution.

 

[Greg S]

I understand what you are describing so a few questions to clarify. I'm a 1911 guy and familiar with trigger slap when installing new ignition systems. It all boils down to tollerance stacking and individual parts movement clearances.

I have a G19 and understand the trigger chewing up your finger pad. Easy solution for a G 19 is to use a smooth G17 trigger or take the serrations pff the existing trigger face with a rat tail file #0, #2 then some sand paper. A world of difference during high round count sessions.

Have you or anyone else insta lled an aftermarket connector with an overtavel stop. If so, remove and reinstall the factory connector and try. My understanding of the Glock ignition system leads me to believe an after market connector has been added with an overtravel stop that is cut alittle tight. There is enough room to drop the striker but under recoil the gun or trigger finger is moving allowing the trigger bar to rise up allitle and get caught by the striker as it returns to battery. Also the firing pin block couls have a bur on it and as it comes back into battery is catching on the trigger bar.

To diagnose firing pin block interferance, remove or bypass and try it.

Do you get.trigger slap on the last.round in a mag?
..

 

[Infinity]

Greg, the gun is completely stock from the factory. I'm going to take your advice as plan B as I've been reading up on this quite a bit. Plan A is to depress the trigger safety (of course with the gun unloaded) and file/sand/polish it until flush with the trigger. If I mess it up, it is a $15 replacement part. If that doesn't work, I will look into the overtravel, etc. course of action. Thank you again for the articulate and well thought out reply (you can tell you're a 1911 guy),
Adam

 

[Infinity]

Ok all, problem solved for those that are interested. I figured out that the trigger safety was protruding too much to the point where, during the heavy trigger pull, it was just short of cutting my trigger finger. I unloaded the weapon, took the slide off, depressed the trigger safety, and sand/polished it until flush with the trigger. I figured if I messed up, it is only a $15 replacement part. Bottom line, Mongo happy! Thank you all for your contributions.

 

[Old Fart 2]

Greg S and Infinity have the correct answer but I would like to add the following comments. Trigger slap is normally something a shooter does to the trigger while shooting. This happens to be the opposite ... something the trigger does to the shooter. It does hurt.

I have a Glock 21 Gen 3 and a Glock 17 Gen 4. The G21 slaps my trigger finger making it almost impossible to shoot well. You think recoil and flinch make for poor shooting. This is worse. Unless you have experienced this unpleasant phenomenon, its hard to describe. It is the trigger safety bar hitting your trigger finger when firing because it sticks out too far at the end of trigger press.

When getting ready to sand and polish the safety bar, there is a trick you should note. The problem is the safety bar protrudes too far forward when the trigger is pressed fully to the rear. When sanding and polishing, the key is to hold the safety bar fully to the rear within the trigger while performing that work. If you don't hold it to the rear when removing polymer, you may end up removing too much polymer. What you want to achieve, without removing material from the trigger, is a totally smooth trigger face and safety bar interface with the trigger pressed fully to the rear. My solution is shown.

I placed the trigger & safety assembly in a padded vice that held the safety bar fully rearward. Caution: Too much clamping pressure will crack the trigger mounting hole. Then, remove excess safety bar with a Dremel drill with fine grinding wheel on slowest speed to avoid heat. The excess trigger bar was removed without touching the trigger surface. Finally I polished the assembly until the trigger face was one smooth surface and then cleaned out all polishing compound with Hoppes # 9 (old school for old farts). You don't want to leave any grit in the interface to ensure the safety bar functions properly.

In the attached jpg, I indicate with red vertical lines where the vice clamps the assembly to ensure the safety bar is fully to the rear. Also, I show a red line indicating where the original safety bar was protruding from the front of the trigger with the trigger fully pressed. That is the ouch part that no longer exists. Took it out today and shot 100 rounds of 230 gr ball ammo @ 880 fps. No pain. First time I've shot more than 20 rounds at a time from this gun. It's not a recoil issue. I've read threads from other sites blaming the shooter ... improper grip ... etc. etc.

I think Glock simply missed this on several model guns, mostly higher power guns. Fix it and have fun.

 

[Downtown]

I'm guessing this is your first post. Welcome. I'm assuming this because newcomers always seem to bring back long dead threads. I've often wondered why, perhaps a old search or something brought them here.

 

[Vivacious Stallion]