Reduced capacity double stack magazines

[natedog]

How are double stack magazines (say, for the Beratta 92FS-15rds.) made to be 10 round magazines? Longer follower/ spring?

 

[Black Snowman]

On my Glock 22/24 mags they are tapered their whole lengh instead of just the top so that even the old springs and follower won't work in them.

 

[James Bondrock]

I don't know which this specific gun uses, but generally there are two ways. One is to shorten the mag body and put a floorplate in that has a higher "roof", with a corresponding shorter spring. This decreases the internal capacity. The other is to dimple the sides of the mag body near the bottom. These protrude inward and prevent the follower from being depressed far enough to insert the evil 11th round. Around the mag body at these dimples is a score line. If you try to hammer the dimples out with a mandrel, the mag body will break off at this line.

 

[SouthpawShootr]

I think Beretta crimps the mag near the bottom enough so that the spring will compress enough to function with 10 rounds, but will not hold 11. Manufacturers have to be really careful about this, they'll be in deep if mags leave the factory that will hold more that 10 rounds. Also, they're under pressure to make design changes so that the mags cannot be easily convertible to greater capacity, so simply changing springs and followers won't work.

I see I got beaten to the punch. Oh, well.

 

[DMK]

CZ-40B magazines have dimples molded into the bottom of magazine body that prevents the follower from going down far enough to fit anymore than ten rounds. Just in case somebody attempts to cut the dimples out, they laser cut the mag all the way around except at the dimple, so it would fall apart if you removed them.

A pair of Mec-Gar S&W 59 mags I own have shorter bodies and a solid plastic extension is added to make up for the missing length.

 

[SouthpawShootr]

A pair of Mec-Gar S&W 59 mags I own have shorter bodies and a solid plastic extension is added to make up for the missing length.

Unfortunately, this design precludes changing the baseplate and generally annoys the hell out of me when I encounter this on compact guns. I like being able to put grip extensions and so forth on mags that need it.

 

[FireInTheHole]

Beretta 92 10rd mags are physically different than 15rd.

They are indented down the middle ~3mm on each side. Nearly impossible to alter I might add.

EDIT: while these mags are still "double stacked" the rds are nearly singlestacked in the mag to the the deformation. I hate clinton mags!