M&P15-22 Mag Mod

[Jubz]

Thought I post this with a searchable title.

Here's an easy mod for the M&P15-22 10 round mag in a 25 round body, to make it 25 rounds (for use outside of CA) and easily convertible back to CA legal 10 rounds (I'm CA based).

The 25 round mag body utilizes a roll pin that is not pressed into the manufacturer's internal hole, and freely drops out when you drill a hole in the right spot. This is much easier than breaking the pin with a hammer and long screwdriver. After the mod, you can drop back in the roll pin and tape over, or use a limiter that also visually indicates 10 rounds; shown as the orange limiter in the below diagram.

The mod:
1. Center punch a mark below and inside the indicated ribs, 3/16" or .2" distance.
2. Use a 1/8" drill bit in a pin vise, and hand drill a hole angled into the rib so the drill also starts cutting into the rib, then straighten out perpendicular as you hand drill so your completed hole includes a small portion of the rib.
3. Stop hand drilling when you feel the drill hitting the roll pin; remove the drill, turn it over and the roll pin should freely drop out.

- Hope this helps.

Diagram:

 

[photoracer]

Thought I post this with a searchable title.

Here's an easy mod for the M&P15-22 10 round mag in a 25 round body, to make it 25 rounds (for use outside of CA) and easily convertible back to CA legal 10 rounds (I'm CA based).

The 25 round mag body utilizes a roll pin that is not pressed into the manufacturer's internal hole, and freely drops out when you drill a hole in the right spot. This is much easier than breaking the pin with a hammer and long screwdriver. After the mod, you can drop back in the roll pin and tape over, or use a limiter that also visually indicates 10 rounds; shown as the orange limiter in the below diagram.

The mod:
1. Center punch a mark below and inside the indicated ribs, 3/16" or .2" distance.
2. Use a 1/8" drill bit in a pin vise, and hand drill a hole angled into the rib so the drill also starts cutting into the rib, then straighten out perpendicular as you hand drill so your completed hole includes a small portion of the rib.
3. Stop hand drilling when you feel the drill hitting the roll pin; remove the drill, turn it over and the roll pin should freely drop out.

- Hope this helps.

Diagram:

You have to be careful doing that possibly. Not sure about CA but many places with ammo mag restriction you can't legally make it easily convertable from one size to the other, unless you are allowed to own larger capacity mags or an older mag is grandfathered in.

 

[roushstage2]

Such mags in CA must be permanently modified to hold 10 rounds or less if you aren't exempt, but "permanently modified" is not defined in CA law. There's obviously no grandfathering as the 15-22 uses a proprietary mag and didn't exist prior to 2000.

 

[laskt9]

There's no need to drill those out. Just take out the bottom and use a long screwdriver to punch the pin out

 

[speedyquad]

There's no need to drill those out. Just take out the bottom and use a long screwdriver to punch the pin out

i have done this to two 10 rd mags(no restrictions here in PA) following the instructions found on this very site...

 

[Airrage]

im still not sure why people are drilling the pin out when it can be easily taken out with long screw driver with a tap of the hammer a few times!!!!

 

[Raydee]

The OP clearly stated that this is so you can drop the pin back in and convert it back to 10 rounds.

 

[billwill]

Just put a long flat blade screwdriver on the pin inside the mag and whack it with a hammer, this has been done a thousand times already!

 

[laskt9]

The OP clearly stated that this is so you can drop the pin back in and convert it back to 10 rounds.

But why would you want to? Just load 10 if you only want to shoot 10. Unless you live in a state where more is illegal in which case modifying your mag in the first place is illegal.

 

[photoracer]

But why would you want to? Just load 10 if you only want to shoot 10. Unless you live in a state where more is illegal in which case modifying your mag in the first place is illegal.

That's what I was saying. In those states where you would only be able to own a ten, owning a mag that can be converted quickly would be at least a class 2 misdameanor or a class 6 felony, just as a guess.

 

[roushstage2]

Here's the problem I see when reading what the OP posted (at least for he and me being CA residents): if you did as the OP suggests and simply drop the pin back in and slap a strip of tape on it, what happens when the tape falls off? What happens if a LEO is inspecting the magazine and the tape had fallen off or he removes it and the pin simply drops out? I'm certainly not one of the rivet/epoxy guys, but using a piece of tape for permanence is asking...begging to be in trouble.

 

[Jubz]

Here's the problem I see when reading what the OP posted (at least for he and me being CA residents): if you did as the OP suggests and simply drop the pin back in and slap a strip of tape on it, what happens when the tape falls off? What happens if a LEO is inspecting the magazine and the tape had fallen off or he removes it and the pin simply drops out? I'm certainly not one of the rivet/epoxy guys, but using a piece of tape for permanence is asking...begging to be in trouble.

I'm actually with you on this re: not using tape, I shouldn't have said that which is why I went the 10 round limiter route and not deal with the pin at all.

YES, in CA it's supposed to be a permanent 10 round mod, though this restricts the ability to disassemble and thoroughly clean the mag after a day of dropping in the dirt while doing various outdoor run & gun events.

So an addendum to my OP, after inserting the 10 round limiter, you are suppose to make this mod permanent and not be convertible, i.e., glue/rivet the floor plate. Or, after using the 25 round mag outside of CA and to use back in CA (or other states with restrictions on max rounds), reinsert the pin and epoxy over the hole to make it permanent.

Though I've seen and read about knocking out the pin with a hammer and screwdriver, I just wanted to approach this without causing possible deformation to the inside surfaces where the follower glides over. Once I knew the exact location to drill, hand drilling with a 1/8" bit in a pin vise literally took 30 seconds.

 

[roushstage2]

That's the thing though, "permanent" is not define in the law. I am one of the many under the belief that using a magazine block is permanent because if you removed the floor plate and took the lock plate (which is now a magazine block in it's place), spring and follower out, you now have a parts kit. Parts kits are legal to own in CA, so that's that...for me anyways.