Has anyone tried to add +2 or whatever to their ban-state 10-rd Glock mags? I know there are a bunch of different aftermarket baseplates out there for Glock mags, but they all say "not for 10-rd mags" due to the different internal geometry of limited mags. I've got a Glock 17 with a bunch of 10-rd mags, and i wanted to add capacity. Has anyone been able to figure this out? Ultimately, i'm buying some of PK90's 15-rd Glock 17 mags, but was hoping i could so SOMETHING with my existing 10-rounders.

Yes, i have and it does work. But there are caveats...

 

The extended base pads fit the mags just fine, its the spring that becomes an issue. The length of the spring, when used with the extended pad, is soemwhat short and the top round in the mag is under so little tension, you may have feeding/lockback issues with it.

 

To fix that you need to get the special Wolff magazine spring for the 10-round mags. This spring is narrower to fit in the ribs and both longer and +10% stiffer to give you better tension up top and to further bolster reliability. 

http://www.brownells.com/magazines/handgun-magazines/magazine-parts/magazine-springs/semi-auto-extra-power-magazine-springs-10-power-spring-3-pak-fits-glock-reg-10-rd-17-17l-sku969-000-015-27358-37092.aspx

 

Because of the spring length, you're pretty much limited to the typical +4/5 pads you commonly see in competition (but then thats all we can legally add anyways). Any longer than that and the spring wont be able to cope with the added internal length and fall short of pushing the follower to the top of the mag body.

 

Also, and this is the biggest downside, adding extended base pads to the 10 round mags doesn't reliably get you any more usable capacity. Due the the nature of the ribbed internal structure of the mag tube to limit it to basically a single stack configuration, if you let the follower drop down below the bottom of the mag and into the cavity of the extended base pad, its not really well guided and tends to hang up when trying to return upwards back into the ribbed mag tube, especially when there is ammo on the follower that is also getting caught up down there. So for the price of the extensions plus springs, if you're looking for capacity, you can get +1 (maybe +2) before things go south so its not much worth it from that perspective. If you compete and want longer base pads to use with a mag well, you can do it this way just to get the dimensions you need.

 

I can tell you that slamming a 10rd glock mag filled to the brim takes some force to seat on these 9mm carbines that ruin Glock mags, but with the extension there is a lot more easy to seat it home.

www.gunsprings.com is Wolff Springs website.  I order direct from them and shipping is fast. 

Hmm. So it looks like the cost will end up being the same as buying new mags, plus a potential loss of reliability. I may end up doing 1 just as a beta test and see how it works, then decide on converting the rest. Thanks for the info.

I have configured a few 10rd G17 mags with the Wolff springs and +5 extensions and it works fine. Just don't try to stuff 14 rounds in it, keep it at 10, 11 or maybe 12 and you're ok. Again, its fine for added length, but for extra capacity its not worthwhile. Get pinned 17 rounders.

 

If you want to run a cheap experiment, ArmsUnlimited has a real nice +5 aluminum extension for $19.99. They are not your typical brand so they are somewhat discounted but are milled from billet aluminum, anodized and of decent quality so far as i can tell. They don't come with any spring at all which accounts for part of the discount, but IMHO, most of the aftermarket extensions are WAY overpriced for a small piece of aluminum or sometimes plastic. Frankly $40 for a plate and a spring is robbery. Time will tell if they are durable as i plan to be putting them through the ringer dropping them in the gravel at matches. I I have personally used these and so far they are holding up.

 

https://www.armsunlimited.com/Extended-Glock-17-22-Smith-Wesson-Pistol-Base-Pad-p/fs-mbp.htm