Anyone have KCI brand Glock mags function properly in their JR Carbine?

st1264

st1264

CGN Ultra frequent flyer
Rating - 100%
156   0   0
Location
Windsor ON
I bought a .40 KCI mag to try in my JRC, due to the price point and lack of stock of OEM Glock mags. I'm getting jams and failure to feed every other round. Mag sits too high, bolt tearing up the top of the mag. Genuine Glock mags work perfectly in my JRC.

Anyone have a JRC and KCI mags function properly in it? Did you have to alter the mag in some way to function properly or did it work right out of the box? Any suggestions for me to fix this particular mag? I have yet to try it in my .40 TDC, will go to the range on Wed or Thu to see if it works in that carbine.

Thanks.

KCImags0001_zpse9520ea5.jpg
 
I use a 10/33rd Kci in my 9mm JR. Functions almost perfect, out of the hundreds of rounds fired with that mag I doubt I've even had 10 FTF. Mine must not sit as high as yours because my mag isn't ripped up quite like that at the top. There are some marks though.
 
I ordered four KCI 10/31's (only one arrived in the damaged box..) for 40S&W so I've got the one loaded to 10 and sitting. These KCI's you will find they probably work fine until you store them loaded and then the springs get soft. Springs aren't supposed to get soft unless it loads/unloads hundreds or thousands of times. Break-in is one thing, as my glock mag that came with the JR was fairly strong to thumb load and after a few unloads it reached a consistent state. KCI's just get weak.

In a while I'll have a better idea of the 10/31. I may even take a trip to the USA so I can pop the rivet and fill it to max, and return in a few months and check that mag again.. then reinstall the rivet and come back with it. Or I could jury-rig something to contain that spring and compress it as though it is a full mag but I won't get the "feel" from unloading each round by thumb. The last three are the most important test, apparently.

Anyone know what aftermarket spring would fit this high-capacity mag?
 
st1264 said:
So it's most likely the spring that loses it's tension, that is the culprit?
Click to expand...

as best as i can tell, the spring is the primary culprit. Ive done a lot a reading across various forums about these mags, and it isn't immediately simple to find them all because they're often referred to as Korean mags which obscures the issue with Khan mags, or specifically referring to glocks, or they don't mention calibre or they don't mention capacity. The typical response is "i just bought a kci mag for my glock and it runs fine." If it didn't run fine there would be a warranty or people wouldnt buy them at all. The problem is when you let them sit loaded, and mags shouldnt have this problem at all.

So they recommend you change the follower, spring, and floor plate. And for that cost you may as well just buy a glock mag and save the headache. I sourced an international shipper for these springs and I'm confident my slightly-old KCI 40S&W 15-round mags can be fixed to be "reliable".

In the JR thread I mentioned I had to shave some plastic off the inside of the feed lips (top half-inch of the mag) so there isn't a friction problem, and I deburred the inside where the follower could rub. The spring should prevent the follower from jamming (uneven pressure front to back) so as long as the follower can fall though, you probably shouldn't need to replace that. I have not found anyone who can explain which glock follower I would use if I did want to replace it, but it appears to be the "#5" model. The glock mag that came with my JR doesn't even have a # code on the follower, even though it is a third-gen mag. The springs can be fixed so they don't fold outwards in the middle to the front of the mag, causing a follower jam, but I don't know what they did to fix it.
 
I rebuild all my KCI magazines with OEM Glock parts so at the end of the day it's just a KCI shell. Sure it might be cheaper to just buy OEM mags but I want 10/17, and OEM 10/17 is a crap load more expensive.
 
st1264 said:
Where did you find these parts and how much are they?
Click to expand...

Glockparts.com

Assuming you have the latest Generation 4 Magazines, exactly what you need to do and how I did it...

OEM G-17 9mm Magazine Spring
Part # SP00448
$6.95


OEM 9mm Follower
Part # SP01812-6
$3.95


OEM Magazine Floor Plate 9mm, .40, .357, .380, 45GAP
Part # SP03206
$3.95

OEM Magazine Insert Plate 9mm
Part # SP01693
$3.95


Total cost to rebuild per magazine $18.80

So if you rebuild 5-6 magazines it's worth the cost.
 
I have 7 KCI 10/33 rnd mags for my 9mm JR. They function perfectly. I have had maybe 1? fail to feed? The only time I had an issue was when my GF started shooting my JR and it would have the weirdest jam I have ever seen, and only when she would shoot it. every other guy that shot it had no issues, so I came to the conclusion my JR hated my GF lol, other than that I have around a 1000 rnds through each magazine, and they still function flawlessly, and I only clean them ever 2000 rnds or so.. maybe.
 
The KCI's have been OK for me.. not great but OK. They take a little work to fir / function reliably. If you are using you JR just for plinking then they are good enough.
 
You must log in or register to reply here.
Back
Top Bottom