Ultimate Smith & Wesson M&P15 Upgrade Guide (2023 Update)

Ah, the AR-15 – a rifle so customizable, you’d think it was made out of Legos! The Smith & Wesson M&P15 may have a loyal fanbase, but let’s be real, there’s always room for upgrades. Like with most things, you start with the basic equipment, but the sweet gear you add makes you feel comfortable and confident. Plus, with its reputation and affordable price tag, the M&P15 is a great starting point for any gun enthusiast looking to level up their shooting game.

Is the Smith and Wesson M&P 15 Good?

How does Smith & Wesson get away with this kind of pricing on a gun like this–one that actually has a reputation for working really well? Volume discounts, mainly. Smith & Wesson makes most things in-house and controls a ton of its own parts production.

Smith makes great guns. This one is no exception. Admittedly, this is an entry-level gun. As an AR-15 goes, this is a suitable starting point. But there are a lot of additions you can make here that will make the gun more functional and ergonomic.

It is a S&W, after all. There’s more than a century of quality behind that name and, for many, that reputation is a kind of guarantee.

The Smith & Wesson M&P 15 Sport II CTS-103 Package

At the time of writing, the Smith & Wesson M&P 15 Sport II CTS-103 Red/Green Dot package is currently one of three optics package deals that they offer. The other two include one with a Magpul carbine handguard and the other is a CA-compliant rifle. That leaves this one to be the most affordable plain Jane optics package. A rifle ready to be upgraded!

This is a normal Smith & Wesson M&P 15 Sport II AR, with the addition of an affordable starter red/green dot from a reputable company. Otherwise, you can call this a bog standard AR-15.

Whatever approach you pick, any Smith & Wesson M&P Sport II upgrades should be easy to do, and since you won’t break the bank buying the base gun, you should have little trouble justifying the additional cost of upgrades or accessories.

Upgrading The Smith & Wesson M&P 15

The journey to a finished rifle, one that will truly meet your needs–individually–may begin with an M&P15, but there’s a lot about this gun that can be customized as easily as any AR-15. This guide will point the way to some functional options for add-ons and upgrades that will take this rifle to the next level.

Let’s step back and look at the appeal. The M&P 15 is Smith’s entry into the high-production, entry-level AR-15 market. There have been Black Friday deals and blowouts in the not-so-distant past that would see advertised prices under $500.

I’ve been in gun stores that had pallets of these that they’d marked down to about $350 a pop. This was a different era, of course, even if it wasn’t all that long ago chronologically. So there are a lot of M&P 15s out there in the wild, and my gut tells me that a lot of them are sitting in safes as a kind of insurance policy against black rifle bans.

Right now, the M&P 15 is starting at around $800 in most shops, but there are still deals to be had for less.

You can work in stages. A basic upgrade will begin with a stock, a new hand guard, and an optic. A more advanced overhaul would add a new trigger, at least, and could strip the gun down to its component parts.

Smith & Wesson M&P 15 Stock Upgrades

Kicking things off with the back-end business, we have the stock. This is an extremely easy upgrade that just requires a new Mil-Spec stock and a little know-how. Most adjustable AR15 stocks can be removed by pulling downward on the adjustment lever. It needs to be down just enough to clear the index points on the buffer tube.

Most “standard” or “starter” AR15 rifles will come with a generic M4 Mil-Spec stock. These are made to be very basic and have no comfy contours or quality-of-life features beyond the adjustability. If you need a more specific helping hand we have a FREE US Army Manual for AR15 / M4 / M16 available here.

Smith & Wesson M&P 15 Handguard Upgrades

If you want to add more depth to the front-end capabilities of your Smith & Wesson M&P 15, quad rails may be the place to start. While Key-Mod and M-LOK have increased in popularity, an old-fashioned quad rail is still the easiest way to add accessories.

AT3 makes solid quad rails. While they may not be as light as some of the newer polymer forends, they are incredibly versatile.

For those of you looking for an M-LOK freefloat style AT3 also provides a handguard that gives you rail space and M-LOK space.

Smith & Wesson M&P 15 Pistol Grip Upgrades

AR grips are stupid-easy to replace, but few people ever monkey with them. The most common reason may be the attempt to keep all of their furniture matched aesthetically. If you have a Magpul stock and forend, why not have a Magpul grip? There are better reasons, though. Chief among them is ergonomics. Some grips radically change the way a rifle feels in the hand, and that added comfort can make a substantial difference in how the gun feels.

Ergo Grips make some grips that add texture and more hand-filling swells. If you have big hands, especially, Ergo should be on your list.

If you need to dial in the width of the grip for a more slim feel, check out the grips from B5.

Smith & Wesson M&P 15 Trigger Upgrade

The Smith and Wesson trigger can be described as functional. Like many AR-15 triggers, S&W is running with a Mil-Spec design that works but isn’t going to wow you.

Check out the Wilson Combat TTU. It will be a breeze to install and a monumental M&P15 upgrade.

Or take a look at the complete more affordable upgrade from AT3. The AT3 2-Stage Lower Parts Kit has a nickel boron trigger and all of the internal parts you’ll need for an overhaul.

Smith & Wesson M&P 15 Optics

If iron sights aren’t your style, the first thing on your list of Smith & Wesson M&P 15 accessories should be an optic. The M&P Sport II is not a long-range rifle, but it is capable of respectable accuracy at close and medium distances. This makes a low-power variable optic an ideal choice for balancing speed with accuracy at distance.

For a rifle that might be used for hunting, tactical, or defensive applications, the AT3 Red Tail scope will provide everything you need, including the mount.

If you want something that’s purpose-built for close quarters, with the reliability you need for home defense, the AT3 ALPHA is ideal.

For even greater clarity at extended range, check out the Riton Optics X3 CONQUER 6-24×50 FFP Riflescope.

And if you’re looking at using your rifle for home defense, the AT3 LEOS may be a perfect solution.  Featuring a 2 MOA Red Dot, plus a laser sight for putting shots at close range on target, even when you don’t have time to shoulder your rifle.

Smith & Wesson M&P 15 Cleaning

There’s nothing unique about the needs of the M&P 15 regarding cleanliness. Like all AR-15s, and especially those that run on direct impingement, you have to keep things clean.

Brushes, wipes, a few punches, tools for detailed cleaning–understand all of the options is easy enough, once you dive in. Start with this article for all of the details.

Some of the most convenient tools come from Real Avid. From bench-top organization to handy tools for range bags, Real Avid is a great place to begin for those looking to build a tool kit, a cleaning kit, or both.

Smith & Wesson M&P 15 Magazines

Like a lot of other companies, Smith & Wesson works with Magpul. Their ARs typically come with one PMAG. That’s useful, but one is not enough. How many mags do you need?

Balancing need and want can be complex. The bare minimum should be 10 mags per AR. If they’re quality magazines.

Magpuls are rock solid. Watch for package deals and stock up. While they’re not extinct, the 30 round magazine is always an endangered species.

The aluminum mags from Duramag work well, too, for those who are averse to polymer mags.

Best Smith & Wesson M&P 15 Upgrade

No matter where you begin, and there are a lot of M&P 15 models to choose from, this is the ideal starter rifle. At the end of the day, the best upgrades are the ones that are best for you. Keep plugging away until you get it right.

In the event that you do not have a Smith & Wesson but instead have a Ruger or Springfield Armory make sure to check out their upgrade articles! Otherwise, check out our Video side of things.

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One Last Tip

If there’s anyone that knows the AR-15 platform, it’s the US military. As a special offer for our readers, you can get the Official US Army Manual for AR-15/M4/M16 right now – for free. Click here to snag a copy.