Not trying to sound stupid, but have you "plunk" tested your ammo into the barrel itself? I had the same problem and some of my rounds fit my "case gauge" but would not seat in the barrel. good luck..[/QUOTE]

 

Not trying to sound stupid, but have you "plunk" tested your ammo into the barrel itself? I had the same problem and some of my rounds fit my "case gauge" but would not seat in the barrel. good luck..

[/QUOTE]
Not stupid at all. Yes I have plunk tested ammo. The chamber on this G34 barrel is actually bigger than the hundo case gauge that i'm using. So everything that passes the case gauge has decent play when plunk tested in the barrel.

 

What's changed right before this started?

You've used this before in competition?

What's changed in your grip or technique?

 

What's changed right before this started?

You've used this before in competition?

What's changed in your grip or technique?

A couple matches before this started, I installed a TTI trigger kit and an extended mag release. But I ran a couple of matches with them without any issue (also running a 13lb spring).

I have been competing USPSA with this gun since March of this year. Ran well up until 2-3 matches ago now.

My grip is the same. I have a very firm grip. I actually try to copy the stiff grip that Jerry Miculek teaches. At first, I thought maybe I'm rushing the reload and rubbing my support thumb on the slide when re-acquiring the grip. (i'm a lefty). But it doesn't seem to be that. I even put some skateboard tape where my thumb should rest on the frame as a locator pad.

 

While I understand why you do not want to do it, might I suggest that you use a recoil spring in that G-17/34 which is a lot closer to an RSA factory standard weight of, at least, 17#'s.

 

While I understand why you do not want to do it, might I suggest that you use a recoil spring in that G-17 which is a lot closer to factory standard; say, at least 17#'s.

That's my next step. Thank you.

 

15 lbs is still below factory for an RSA. My initial thought was RSA and then weak magazine spring. Do you have a 17lb RSA you could try?

 

Thanks i'm going to put my factory spring back in. This sucks because if that fixes it, that 13lb spring works real nice on follow up shots to bring the gun back down perfectly for the follow up shot on the double tap.

 

Try different mags and different ammo first. Then gunsmith.

 

I have tried about 7 different mags and they're all doing it.

I'm going to try upping the charge to max from the manual to 4.4gr of 231 powder behind 124gr montana gold JHP.

 

Did you verify that your optic's screw isn't presenting into the channel of the depressor plunger assembly? I don't suspect this is it, but I'd check top to bottom.

Maybe you changed a battery and torqued it a bit harder this time?



Or, since it's happening during matches, are you 100% sure the chamber was empty and you didn't inadvertently tried to load on a loaded chamber?

I'm just spitballing since you've tried everything else except a stronger rsa. You did say it was working okay with weaker ones...but that may not mean much unless it was reliable for a long time during that use.

 

Did you verify that your optic's screw isn't presenting into the channel of the depressor plunger assembly? I don't suspect this is it, but I'd check top to bottom.

Maybe you changed a battery and torqued it a bit harder this time?



Or, since it's happening during matches, are you 100% sure the chamber was empty and you didn't inadvertently tried to load on a loaded chamber?

I'm just spitballing since you've tried everything else except a stronger rsa. You did say it was working okay with weaker ones...but that may not mean much unless it was reliable for a long time during that use.

Yes, I actually confirmed that when I first mounted the SRO mainly because I heard it was a problem to look for. Shined a light on the opposite end and looked inside with a magnifying glass. and the extractor rod goes in and out freely.

It is happening after a shot has been fired. So during the cycling of the empty cartridge and loading of a new round.

 

Extractor "chipped?"

Squashed magazine springs are a suspect but a few months shooting spread over 7 magazines does not sound like a lot of wear.

 

I actually just pulled it all apart and I have it in front of me while you kind folks are helping me. Extractor is clean and oem sharp. I did note the plunger spring that locks in the extractor is a TTI spring and is quite a bit lighter than stock. Wondering if I need to put this back in. Shame cause it breaks right at 3# on my wheel spring scale.

 

I didn't know that the extractor spring affects trigger pull. Go stock and see what happens.

 

If you think you are riding the slide stop or slide, shoot it left handed only. Also 4.4 grs of 231 sounds a bit light. What did it chrono at. I usually bump a load by .2grs because Dillons throw +/- .1 grs with sugar powders.

 

Well one manual says max 4.4, the other says 4.5. I have fired this gun in stock form with 4.4 before without any issue. I lowered it to 4.3 earlier this year since after chrono it made 130 minor pf.

 

TTI trigger and a non-Glock spec. recoil spring weight....hmmmm.

 

So the case partially in the chamber is a fresh cartridge, not just a case that didn't extract, correct?
How often is this happening? Can you replicate during range and practice, or only under stress?

Are the mags and springs stock or do they have extensions or other go fast mods?

You have a lot of variables going on, with reloads, springs, trigger mods. Being lefty, you can rule out the slide stop lever. Could be the skateboard tape.

The round on the bottom has the edge of the breech fully behind it or is it still sitting under the slide? <--- this is important.
It's either pushing 2 rounds on the return, or it is dragging the 2nd round <-- I suspect it is the latter, which would mean your slide timing is off, and you need to change your RTB dynamics: increase your load. Short stroking and or lack of slide velocity is my guess.

You are chasing performance, and giving up reliability.

 

So the case partially in the chamber is a fresh cartridge, not just a case that didn't extract, correct?
How often is this happening? Can you replicate during range and practice, or only under stress?

Are the mags and springs stock or do they have extensions or other go fast mods?

You have a lot of variables going on, with reloads, springs, trigger mods. Being lefty, you can rule out the slide stop lever. Could be the skateboard tape.

The round on the bottom has the edge of the breech fully behind it or is it still sitting under the slide? <--- this is important.
It's either pushing 2 rounds on the return, or it is dragging the 2nd round <-- I suspect it is the latter, which would mean your slide timing is off, and you need to change your RTB dynamics: increase your load. Short stroking and or lack of slide velocity is my guess.

You are chasing performance, and giving up reliability.

Well you absolutely hit the nail on the head several times here especially that last statement. I honestly just want to get classified in carry optics and move on haha.

1. Yes it's a fresh cartridge, all spent cases have been extracted.
2. I went to a static range last tuesday and fired off 200 rounds w/o a hiccup. I was trying to imitate "under stress" situations so i was firing 4-6 shots in double tap, dropping the mag, firing another 6-8 shots then dropping the mag, reloading, repeating until the 200 round reloads were used up. No issue lol. So yes, it only happens at matches under stress.

3. I have 6 stock glock 17 factory mags (4 new) along with 2 other glock mags with +7 baseplates and +springs but I didn't want to mention those since that was adding another variable.
4. The round on the bottom is being pushed by the breech face of the slide. Since I'm a lefty, the only easy way for me to clear it, is to drop the mag, let the top round chamber then reinsert the mag and continue on. But it happens so frequently, the guys at the match are starting to call me "bolt action bob" lol

The thing that's puzzling me the most is, how is the slide getting forward momentum to start chambering that top round and then stroking back to grab the 2nd round?!?! Unless the mag is flicking the top round up with no help from the slide inertia???

I'm definitely trying to chase performance and giving up reliability sadly. Eventually this will go back to complete stock g17 and back in my nightstand but I want a damn decent classification in CO dangit hahah.

 

Have you tried using the Strike Industries Mass Driver compensator? Sounds like you want low recoil and fast follow up. I have a few and love them. So easy to stay on target and the darn thing actually works great.

 

Your quest for performance may be affecting your "shooter" variables since this is only happening under stress or competition environment. Significant what you said in #2. The fix for that is to lay off the Glock, and use the 1911, until you fix your stress induced dysfunction.

Having modded mags is a huge thing to leave out-- but it adds another huge unknown to your twilight zone. But still could be mis-direction from the main cause. "Limp wristing" is an umbrella term that covers all sorts of bad shooter behavior.

I don't understand how mechanically the slide can push on 2 rounds at the same time - perhaps it's not what it seems, and the round below is popping up after you get around to looking at it closely-- since you aren't really looking during a match- or you think that is what's happening, because it's mechanically impossible. What you are describing is not possible.

The most common causes for malfunction are ammo, then shooter, then shooter induced (adding mods, buying bad ammo, doing stupid stuff like not putting it back together properly)... the gun itself is usually last on the list, unless mods were done. That's the elephant in the room.

 

Low powered rounds and magazine spring issues are probably the cause. I would first try to use standard powered cartridges with a factory weight RSA. If you still have the issue, use stock magazines with no extension. If you have it after that, well, I don't think you will.

 

Try posting over at Glock
Pretty much only dedicated competition shooters hang out there. As Single implied, did your issues start with the Taran trigger and non stock recoil spring weight?

 

I would suggest mag feed lips but multiple mags aren't going to go bad at once. You aren't using .40SW mags for 9mm are you?

 

Does it do it with factory full powered ammo? Does it do it with a new mag with a fresh factory spring and no + baseplate on it?

 

It'd be interesting to see, if this is shooter induced malfunctions, would it still happen in 100% stock form.

 

The OP is an experienced USPSA shooter, not some 200 round a year guy. Whatever is going is much more subtle than newbie issues.