View Full Version : Is there a way to convert 10rd SIG mags to standard capacity?

10-04-2011, 9:37 AM
I'm in Colorado btw.

I have five ten round mags for my SP2022 (9mm) and I'd like to have some standard caps. The problem is that standard caps are like $35-$45 and I don't want to spend that much.

I've never seen the standard cap version of this mag so I don't know exactly what the difference is (longer floorplate, follow, etc). Anyone have any ideas on how to make these into 15 round mags? I don't mind experimenting either, I have five so if I screw one up its not that big of a deal.


10-04-2011, 9:39 AM
do you have a link to a pic of your mag?

10-04-2011, 9:41 AM
Yes it can be done, but no as it will not be cost effectly.

10-04-2011, 9:44 AM
Also, MecGar make Sig mags for cheaper price.


17rd $29.99

10-04-2011, 9:48 AM

10-04-2011, 9:52 AM
Yeah, Mec-Gar. They make the factory mags for Sig. The aftermarket ones branded under Mec-Gar's name without the Sig logo work fine and are less expensive.

I don't think you can convert yours, judging by this photo:


If yours are like that then it's just like my CZ 10-round mags. The actual metal body of the magazine is short -- 10-round mag length -- and then the floorplate plastic piece is really tall to extend below the grip. You can't just put a flat floorplate on, because then the mag wouldn't fit inside of the grip and it would still hold just 10 rounds. The normal capacity magazines have a metal body that goes all the way down to the bottom, and then a short floorplate:


What we would both need to do the conversion is a long floorplate just like what's on our 10-round mags, but one that was hollow like the magazine body itself (probably one made of metal just like the magazine). That and a longer spring. PLUS... the bottom of the magazine body would have to be modified to remove the lips that hold the floorplate. Which also means the new extended hollow floorplate would have to be welded on. OKAY... new plan. Buy sheetmetal. Cut magazine body wherever you want. Extend length by welding in sheet metal so the body is now as long as the hi cap version (you do it this way so the OEM lips on the bottom of the mag are still there and you don't have to try to fabricate your own). Put normal hi cap baseplate on and insert longer spring. .....probably easier to just buy Mec-Gar!...

10-04-2011, 9:53 AM
Short case, so no. Maybe that case fits a smaller sig, like some CZ mags do. See what you can get for them from Californians and buy what you really want.

10-04-2011, 9:58 AM
The mag bodies usually will have a crease in them that limits their internal capacity of the usual wide/double column mag to that of a single column mag.....no easy way to get around that.

10-04-2011, 5:20 PM
Standard capacity for your magazine is 10rnds.

The whole idea of the design is not to be convertible to large capacity, as required by the federal when it was in effect.

And you'll likely get poor responses in this forum since most of us are not allowed to manufacture large capacity magazines; we know alot more about turning large capacity magazines / rebuild kits into 10rnd mags.