Comprehensive .40S&W mag in 9mm gun thead...

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seeker_two

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Since this has been discussed in other threads scattered on TFL & THR, I thought it would be good to create a thread where everyone can find this info easily...

1. What .40S&W mags (any make or model) will work in what 9mm pistols (any make or model)?

2. What increase in capacity can be expected?

3.How reliable are these magazines? Are they range-reliable (few FTF, little modification) or carry-reliable (no FTF, excellent reliability)?

Appreciate the help...:D
 
I have tried this w/ my USPs, Beretta 92fs and a XD 9. It works for all 3, w/ added round capacity in each, but still not 100% sold. I use this method only for the range a sometimes for competition.
 
Steyr Pistols

I have a Steyr M9 and a Steyr M40. I have been using one of the .40 mags in my 9mm for about a month now. It has worked extremly well. I first measured the 9mm mags to see how much the .40 Mag would have to be ajusted. It wasn't very far. I used a brass hammer to tap the lips of the clip to the point it needed to be. I can now load 12 rounds of 9mm into my .40 Cal mag. If you have any questions on this feel from to PM me.
 
Ive done it with my PT911...I still had a couple of PT940 mags..
It holds 14-15 rnds and has been 100% reliable.
Typically...ANY gun that is chambered for both will have very similar mags....the earlier PT940 mags were identical to the 911's but the 9mm had the "capacity limiting detents" at the bottom.
Ive seen this work flawlessly in Bersa Minithunders, Taurus/Berettas and Sigs.....Why not?
Shoot well
 
If you guys keep publicizing this, you're going to start seeing 8 & 9 round .40 S&W magazines showing up from the manufacturers.

I believe they're the ones who will get nailed on this if somone decides to get nasty and try to prosecute.
 
OH come on! This is a forum and lets share the info!

I want to know the Ruger situation. I have a Ruger P95 and I want to know which .40 mags will work in it.
 
Now to burst your bubble. As I understand it. IF a person puts more then 10 rds into a post ban mag they are breaking the law. Stupid as it is that is considered modifying a magazine to hold more rds then it is allowed by law to. (something like that) Odds are you will be fine but if you follow letter of law you are not. :(
I made the mistake of cleaning mags for my Glocks one night. When putting G26 and G27 mags together I must have made a mistake and put +1 40 mag on 26. I went to range and loaded up without paying attention. Had a wonderful 12 shot 9mm. and a 9 shot 40. It was a honest mistake that I will not repeat unless ban fails to renew. Would make the 26 a much better carry gun. Worked great for 3 loads. (I was not going to take them apart in a dirty public range while paying by the half hour.)
 
One of the members of the XD/Hs2000 forum sent a letter to the BATF questioning the legality of using 40 cal mags in 9mm guns. They basicly said it is legal. The problem is when you convert a postban mag to hold more than 10 rounds. These mags hold more than 10 rounds of 9mm when they were made. Now if you plan on tweeking feedlips, it has to be kept minor so the mag still works in a 40. I personally have a 40 cal mag that works perfect in my HS 2000 and it works fine in the 40 XD also. Here's the letter. The part about 9mm in 40 cal mags is at the bottom. http://members.aol.com/hs2000fanatic/letter.pdf Mark
 
I agree...Ive looked into it..talked to Class 3 dealers and the feds....there is not a statue that states it cant be done.
Youre not modifying a mag in anyway from working perfectly in the gun it was designed for, thus no law is broken.
If you do tweak it to make it work...then your possibly asking for trouble. This thread IMO is just another thread......
Shoot well
 
Thanks for link. It comes close to answering the question. But as was said it may make a law change so .40 and .45 mags can only hold 9 rds to make up for it.
 
It's not illegal for the owner to use a .40 mag in a 9mm gun to squeeze in a couple more rounds.

However, if the BATF wants to get nasty, they could make a case that the manufacturer is making high capacity magazines because as manufactured, they will hold more than 10 rounds and will fit and function in existing firearms.

So, you're free to load up your 40 mags with 9mm, but if you keep making a big deal about it, the manufacturer may eventually get prosecuted or forced to somehow modify the mags so they can't be used in 9mms any more, or so that they won't hold more than 10 rounds of 9mm.

Example.

Let's say I design a pistol and a proprietary caliber such that the magazine holds 10 rounds of my proprietary caliber. Now, lets say that I designed my proprietary caliber and firearm so that this magazine just happens to be identical to a 15 round 9mm H&K USP magazine. I start cranking out magazines by the thousand.

Have I broken the law? Nope. My mags are designed to hold only 10 rounds of the JohnKSa Supermagnum. If you buy and use the mags in your 9mm H&K USP, have you broken the law? Nope--you didn't modify them and they'll still work in the gun they were made for. Will the BATF let me keep doing that? Not for long...
 
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