How To Upgrade Your S&W M&P 15-22


The Smith and Wesson M&P 15-22 is one of the best dedicated AR style rifles chambered in .22LR. It has magazines that are easy to load and the gun has most the same features as a real AR-15. Since the M&P 15-22 is similar to an AR-15 you can immediately install AR-15 accessories such as triggers, safety selectors, grips, mag releases, and stocks. However there are some things you need to know.

Starting Back To Front

First up is the faux buffer tube. While it is milspec sized and wil fit most collapsible stocks, things get interesting when you want to add sling mounts or fixed stocks.The buffer tube protrusion, that has all the stock detents, is one continuous piece. On a traditional carbine buffer tube the protrusion stops about an inch before reaching the back of the receiver.  In some cases certain stocks utilize this gap to mount the stock. This makes using those stocks almost impossible on the M&P15-22. However the buffer tube is polymer so it is realtively easy to use tools and remove material. Look at the photo below, the previous owner drilled holes to attach a Magpul PRS stock to his M&P15-22.

buffer tube

I installed a Hera Arms CQR stock to my M&P15-22. This wa not a straight forward installation. The area where the buffer tube meets the receiver is a different geometry than a standard AR-15. There was some material that needed to be removed from the stock.


As you can see in the photo above the Hera CQR stock has a QD socket allowing me to use a single point sling. But what if you don’t want to use this style of stock? Well some QD sling mounts will work. You need to find ones that can slide over the buffer tube and clamp down. I had this Troy QD Pro Grade Rifle Sling Adapter. This will fit onto the M&P15-22.

troy QD

Triggered About Triggers

Moving forward down the M&P15-22 we now take a look at the trigger. The M&P15-22 can accept almost any trigger out there. I have a Geissele SD3E trigger in mine and while it cost more than the gun, the triger pull is just sublime. The trigger is worth the price and I can always swap it into a real AR-15 if I want to. Installation of an AR-15 trigger is rather easy and the M&P15-22 is just as easy. The only issue is the safety selector stops. Most AR-15s have thei selector stops at Safe and Full.  For some reason, S&W had selector stops placed at safe and fire. So the safety can only rotate 90 degrees. You will need to remove the semi selector stop if you want to use a trigger like the Franklin Armory Binary Trigger.


Staying with the lower receiver, you can change out the magazine release to an ambidextrous mag release and the mag well can take certain flared magwells. I got mine from a friend. It makes reloads easier and faster.

In the upper receiver the only part you can change is actually one of the more important ones if you like to shoot fast. The factory charging handle is just too small. There are a couple of options for larger charging handles. NDZ makes an aluminum replacement charging handle for the 15-22. They even offer enlarged latches. Those could work but Next Level Armamenthas a better solution. They took their AR-15 charging handle design and switched out the long shaft for one that will fit in an M&P 15-22.


What About Handguards?

When I purchased my M&P15-22, it had a polymer quad rail. Now the new M&P15-22 come with a narrower handguard that has MLOK slots all around it.

quad rail

mlok hadguard

While the newere polymer MLOK rails is nice, it is just not something I want. So what can you do about this? Well Tacticool22 is your answer. The factory polymer handguards are attached to the upper receiver by a propreitary nut and there is no conventional way to get in there and remove it.

quad pieces

castle nut

Tacticool22 came up with a special wrench to help you remove the small castle nut you see above.


Once the castle nut is removed, you can simply slide the handguard off. Next you need Tacticool 22 thread adapter. It screws onto the receiver giving you threads like a traditional AR-15 upper receiver.

thread adapter

With that adapter the world is your oyster to mount any freefloat handguard you heart desires.

angry gun handguarf

The last piece of modification available to you are the magazines and suppressing the 15-22. The standard magazines are single stack 25 rd magazines. There is an alternate choice. Plinker tactical makes a 35 rd magazine for the 15-22.


One issue is that the Plinker mags do not have the exposed follower loading assist like the factory magazines. But they can be purchased on sale for only $12.99 on Gunmag Warehouse.

Next up is suppressing the M&P15-22. The barrel is thereaded 1/2×28 so any muzzle device you want will fit the M&P15-22. I added a suppressor to mine but Innovative Arms makes an integrally suppressed barrel.


This barrel/suppressor combination is considered a single stamp gun. The suppressor is a part of the barrel maing the barrel the legal limit so as to not have to file for SBR status. Besides the overall benefit of being a single stamp and keeping the barrel as short as possible does make the gun lighter. Another benefit to the Innovative Arms design is that it is integrally suppressed.  The barrel is perforated so that any tye of ammo vents gas after it passes them. Thus any rounds you use whether it  be high velocity or standard velocity will drop down to sub sonic levels making this gun extremely quiet. The only bad aspect of the Innovative Arms integrally suppressed barrel is the cost. It costs about $1000 to have your barrel converted.

What have you learned?

At first glance the M&P15-22 seems limited in its potential to be modified and personalized. However the sky’s the limit with just a few dedicated adapters and some tools. These guns are extremely fun to shoot and adding your own personal touch to your firearm is one reason they are so fun.

  • Steve Moneypenny

    Nice Article Nick!

  • Anon E. Mouse

    “What have you learned?”

    I learned that I should never have moved into a blue state 35 years ago. 10 round mags, no suppression, fixed stock.

  • ※ MadMonty ※

    I just want to know where that LVOA-C handgaurd came from.

  • Robt Greener

    So glad I keep finding Jewels like this article, I love my S&W M&P 15/22!
    It has already been modded almost as much as I desire, but this really looks like I need to buy another one… That is the Best Answer! Keep it coming Nicholas!