Transforming an AR-15 into a Home-defense Rifle


A few weeks ago, I discussed my plan of using the upcoming Crimson Trace Midnight 3 Gun Invitational to choose, equip, and practice with guns I’d use for home defense. Since then, I’ve decided to use a Smith & Wesson M&P 15 OR for the rifle. It’s a standard AR-15 design with a notable exception: instead of the classic A2 fixed front sight and gas block, it comes equipped with a rail gas block. M&P 15s run reliably and are cost-effective, making them an excellent choice for a home-defense gun.

The before photo.
The “before” photo.

Gearing it up for both the nighttime 3-gun competition and home defense use requires some tweaks. Here’s what I decided to do.

Installation of the quad rail was easy. The author didn't need any tools.
Installation of the quad rail was easy. The author didn’t need any tools.

Rail for lights and lasers

The Smith & Wesson M&P 15 OR comes with a standard round plastic handguard. It’s comfortable and does a good job keeping your support hand cool when the barrel gets hot, but doesn’t have attachment points for rail accessories. I chose to replace it with a BLACKHAWK! AR-15 Carbine Length 2 Piece Quad Rail Forend. It offers rails on top, bottom, left, and right, and has great ventilation in between said rails to let the barrel cool.

Installation is a snap. You don’t need tools, not even a hammer. Just remove the existing handguard by pulling down the delta ring in front of the receiver until you can pry the existing handguard halves out. The new BLACKHAWK! handguard also comes in two pieces, so put them in the same way. After they are pressed in place, you bolt the two halves together. It’s not a free-floating solution, but it’s rock-solid and you don’t have to do any serious construction work to install it on your rifle.

A little detail that makes a big difference

I also chose to install a BLACKHAWK! Offset Safety Selector. This is one of those “oh duh why didn’t I think of that” inventions. It relocates the safety lever itself 45 degrees so you can easily reach it with your thumb without shifting your grip. It’s a great aid for safety and usability, and for competition—it might just help you avoid a procedural penalty for not engaging the safety on your rifle.

Here you can see the offset safety and sling mount. The sling mount has the loop on both sides, so both parts are fully ambidextrous.
Here you can see the offset safety and sling mount. The sling mount has a loop on both sides, so it is fully ambidextrous.

Adding a sling

While I technically don’t need a sling for the Midnight 3 Gun event, as you either carry your rifle or stage it in a barrel, I like having one on my home-defense rifle. It’s not that I’m intending to hike miles on end and need a better way to carry my rifle, it’s more for being able to drop the rifle if I want or need to use both hands for something. Think of an AR sling as a holster for your rifle. When you’re not actively using it, put it on safe and drop it, letting the sling carry the load.

I chose the BLACKHAWK! Storm Sling RS. It’s a single-point sling that clips to a loop right where the receiver and buffer tube connect. It’s got a quick-detach buckle if you need to remove your rifle quickly. I like it because it has a bit of flex and bounce in the elastic material strap and it’s simple. Loop it over your head and shoulder and you’re good to go.

You will most likely need to add a sling mount. I chose the BLACKHAWK! AR-15/M4 Ambidextrous Sling Adapter. It slides over the buffer tube and bolts into place, do you don’t need to take apart your rifle to install it. Easy.

Lights and laser

Now that I had the “platform” adjusted, I added my accessories for night shooting. On my front handguard, I installed a Crimson Trace MVF-515 light and laser vertical grip. I love this piece of gear. A green laser and 150-lumen tactical light are mounted on opposite sides of the post. You activate one, the other, or both with pressure pads on the vertical post itself. The pressure pads are on both sides to accommodate righties and lefties. More importantly, it takes a good deliberate squeeze to activate the light and laser, so it’s easy to carry and shoot the rifle without engaging the lights and laser if you want to remain stealthy and ninja-like.

Here's an awesome piece of gear for shooting in the dark - the Crimson Trace MVF-515 Vertical Fore Grip light and laser.
Here’s an awesome piece of gear for shooting in the dark: the Crimson Trace MVF-515 Vertical Foregrip light and laser.


My choice of optics for home defense and the Midnight 3 Gun was an easy one: Aimpoint.

Here’s why. Aimpoint designs their optics to run forever on a single battery. This means you leave it on, all the time. For a bedside rifle, you never, ever have to worry about remembering to turn on a red dot sight—it’s already on. The Aimpoint PRO model can run for three years continuously without a battery change. If you want to be super-duper cautious and never worry about battery failure, just set yourself a reminder to replace the batteries once a year. I’ll spend the $3 for that type of peace of mind.

The Aimpoint PRO is a 1x optic with adjustable red dot intensity, so it’s good to go out to a couple hundred yards. With a standard 5.56mm or .223 Remington round, if you zero it at 50 yards, it shoots flat enough out to 200. Since I’m ancient and going blind, I’ll be trying out an Aimpoint 3xMag with a twist mount. This mounts right behind the Aimpoint PRO and turns it into a 3X fixed red dot optic for longer shots. Word is there are 250-yard targets (in the dark!) at this year’s midnight match so I’ll want that. The twist mount allows you to move the magnifier out of the way when you don’t need it and flip it into place when you do. I’m really looking forward to working with this.

I’ll confess—if you’re looking closely at the photos, you’ll see a couple of other tweaks I made not yet mentioned here. While luxurious, I didn’t feel them “necessary” for a night competition or home-defense rifle. I added a BLACKHAWK! Ergonomic Grip just because I like them. I also replaced the buttstock with a BLACKHAWK! Adjustable Carbine Buttstock. Just because. Also, I find it has a wider and smoother comb that is helpful for establishing a good cheek rest for longer shots. I’m probably gonna stick Smith Enterprise Vortex flash hider on there, too, just because they’re cool. That should also lower the muzzle flash significantly when shooting in the dark. I haven’t yet mounted an electric chainsaw on the bayonet lug, but am seriously considering it.

So those were my customization decisions, what would you do?

Tom McHale is the author of the Insanely Practical Guides book series that guides new and experienced shooters alike in a fun, approachable, and practical way. His books are available in print and eBook format on Amazon.

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