I need a 20 rd mag for a .40 SW99

[JM.40Cal]

Ok, like the subject says, I need extended magazines for my .40 SW99. I guess Walther made 20 rd mags for the 9mm, but not the .40.

First question: Would the 9mm magazine work, as is, with .40 caliber rounds in my .40 caliber handgun? I ask because this is possible with SOME makes and models of other handguns (SIG, for one).

Second question: If that's not possible, I'm going to have to make my own (or have them made for me). Does anyone have any experience doing this, or do you guys know of anyone who would do this for me?

In case anyone is wondering why, I'm going to be using my SW99 in USPSA matches. I'd like to compete in Limited Division, and my 12 round mags would put me at a big disadvantage.

 

[JM.40Cal]

Ok, like the subject says, I need extended magazines for my .40 SW99. I guess Walther made 20 rd mags for the 9mm, but not the .40.

First question: Would the 9mm magazine work, as is, with .40 caliber rounds in my .40 caliber handgun? I ask because this is possible with SOME makes and models of other handguns (SIG, for one).

Second question: If that's not possible, I'm going to have to make my own (or have them made for me). Does anyone have any experience doing this, or do you guys know of anyone who would do this for me?

In case anyone is wondering why, I'm going to be using my SW99 in USPSA matches. I'd like to compete in Limited Division, and my 12 round mags would put me at a big disadvantage.

 

[stfram]

Originally posted by JM.40Cal:
First question: Would the 9mm magazine work, as is, with .40 caliber rounds in my .40 caliber handgun?

No.

Back during the ban, some folks took .40 mags and found that you could stuff 15 rounds of 9mm in them.

Going the other way around, MIGHT get you two extra rounds of capacity, but you'll likely get misfeeds. Probably at the worst time.

Not to mention that the 20-round 9mm mags are gonna cost you a bundle if they even can be found...

Buy a regular 9mm 15-shot P99 mag, and see how that works with .40 before you spend a bunch of money.

If it don't work, you're out $40 or so, and you can sell the mag at a slight loss to someone else.

Second question: If that's not possible, I'm going to have to make my own (or have them made for me). Does anyone have any experience doing this, or do you guys know of anyone who would do this for me?

All I can say is..good luck. Contact a company like ProMag, or maybe MecGar, since they make the Walther factory magazines...?

Understand that promags have an awful rep, but can be made to work...sometimes.

In case anyone is wondering why, I'm going to be using my SW99 in USPSA matches. I'd like to compete in Limited Division, and my 12 round mags would put me at a big disadvantage.

Clearing jams caused by a Frankenstein mag is going to be an even bigger disadvantage. Just pointing out the obvious there.

Take $600 or so, go down to your local gunshop, and buy a Springfield XD-M in .40 (the only caliber they're currently available in). Those have 16-round factory mags as standard, compared to the 12-round capacity of the regular XD's.

Or for that matter an M&P 40, or a Glock 22 which both boast 15-shot mags..

It's too bad the Walther shoots so well for you, since it's gonna be a nightmare to get reliable mags that hold more than the factory capacity.

 

[handgunner356]

I never measured one, but you are limited to a 140mm overall mag length in USPSA. I'm just guessing but I say if you could have a factory mag exteneded you would only gain three more rounds and stay within the overall length requirement, it would be something to check if you do find a 20rd.

 

[JM.40Cal]

Thanks for the replies, guys. The more I think about it I will probably just stick with my 12 rounders. I had a bad meet last weekend and realized I have a lot of improvement to gain in other areas before I worry about a few extra rounds

.

ETA: I'll probably be moving to a 1911 platform for competition in the long run, anyway. I'd like to get a 1911 that is suitable for carry, but can hold her own at competitions as well. Lord knows there's only a few..like maybe a billion or so options as far as that's concerned.

 

[SW99Fan]

Stay away from Promag magazines, they are junk, they make alot of hicap mags for alot of different guns, and for alot of gun makers they offer the only aftermarket hicaps available... meggar makes GREAT aftermarket mags and I think they make hicaps for certain models but anything Promag is just plain junk, especially their CZ mags.

 

[drstephennix]

So it is possible to use a 9mm mag in a .40? I have a SW99 in 40cal. It was sold to me with a 16rd mag and a 12rd mag. The 12rd is factory, but the 16rounder i have now found is a 9mm mag. It fits perfect, but have not shot the pistol yet. I think its actually holding only 15rds though.