There are a number of shooters—hunting, tactical, defensive, target—for whom the .223/5.56 is simply not enough. While there are intermediate cartridges that will improve on the (mostly alleged) inadequacies of the .223/5.56, those who are most adamant are clear on what they want. They don’t want something just a bit better than the 5.56, they want a .308.

Well, now they can be happy.

S&W’s new M&P-10 is a big brother to the M&P-15. It’s chambered in .308, feeds from .30-caliber Magpul magazines and works like any other AR you’ve ever handled, just with a bigger bore.

The Basics
The upper is a flattop receiver (with a forward assist, no less), so you can mount your choice of irons or optics. This is mated with a gas block out on the barrel that has its own Picatinny rail, so you’ve got a place to park a front sight, folding or otherwise.

The handguards are straightforward M4-type, plastic, lacking an internal heat shield. I don’t see this as a problem, as most shooters have their own ideas about what the “correct” handguard is these days. Faced with myriad aftermarket options, S&W was wise to make it simple and easy to swap out.

The receiver extension (buffer tube) is your standard telescoping stock tube with six stops and comes with an M4-style buttstock on it, bearing the S&W logo. The receiver extension tube has a normal buffer and spring, bearing on the expected hybrid carrier. The rear half of the carrier is .223-size, to fit within the confines of the extension tube. The front half of the carrier, and the bolt, are .308-size. Interestingly, the firing pin has a return spring to control firing-pin movement on chambering, I would assume. Curiously, it acts to push the bolt back into the carrier, making reassembly an almost three-handed operation.

The lower receiver is the expected .223/.308 amalgam. The rear portion—holding the trigger components—is .223-size. Forward of that, to contain the .308 magazine, the receiver is larger in width and length. Really, there’s no other way to do it unless someone is willing to design an all-new .308-size hammer, trigger and other parts. Also, the pistol grip is .223-size, so you can swap that (along with the handguards and buttstock) for the one of your choice.

The barrel is a lightweight-for-.308 tube with a clamped-on gas block. The  muzzle is threaded for a flash hider, and the hider that comes on it is a tad large for my tastes, but “large” is a relative term. What really matters is, does it work? Yes, although some .308 loads provide more flash than any flash hider can manage, short of a suppressor.

The barrel twist is 1:10, so it will properly stabilize any bullet weight you are likely to be launching out of a .308 case—or out of this rifle.

The gas system is the classic direct-impingement system, just like the original. I don’t know if S&W is considering a piston system. Such things are closely held secrets. But even if the company is contemplating pistons, the DI system is faster to market and simpler as well.

Controls, Ergonomics
What’s different? A few things, and they are all good things. First the safety’s ambidextrous, and the two sides are different sizes. If you want the larger one on the right side (for left-handed shooters), you can swap it from one side to the other, away from the right-hander’s version. The mil-spec safety selector is not switchable, and despite the screams of outrage from the mil-spec crowd, this is a useful feature. My only reservation on this is that I have seen safety levers that use these small Allen screws loosen during use. It is worth painting-in the screw once you tighten it during the swap.

Along with an ambidextrous safety, the M&P-10 has ambidextrous bolt catches and magazine releases. However, S&W didn’t feel the need to totally resculpt the receiver and add all sorts of design fripperies. The ambi bolt catch is a standard bolt catch, installed on the right side, in an extra bolster created in the forging for the upper. (I can see where that took an experienced die sinker all of a coffee break to grasp the idea from the blueprints and maybe 15 minutes of work altering an existing forging die.) It uses a standard bolt catch lever.

Similarly, the ambi magazine catch is an extra lever on the left side that bears against, and moves, the existing magazine catch. I’m not sure this even involved a small change to the forging die, just a couple more machining operations and new lever. The lever probably took more time and effort than any of the rest of it, and I’d be stunned if it took more than a day. The ambi mag catch lever is nestled just above the lower reinforcement wedge, the rib used to stiffen the 5.56 rear to the .308 forward half of the lower receiver.

The lower receiver also has ribs machined into it on the front face of the magazine well exterior. They are there to provide a nonslip grip for those who shoot with the off hand wrapped around the mag well. I don’t do that, but a lot of shooters do, and that detail is for you.

Bravo, S&W, for actually improving the design and not making it complicated and different.

Oh, the triggerguard is not a mil-spec winter unit. It doesn’t fold and is a curved, integral part of the lower receiver now. Again, good show.

Inside the lower, the firing mechanism is your basic, single-stage, mil-spec design, but not mil-spec parts, setup. The hammer definitely looks like a MIM part, but while that was a big deal to some shooters a few years ago, many manufacturers have solved MIM teething problems, and it has been a long time since I’ve had any problems with such parts.

I tell you this only because someone at your gunshop or gun club is going to pop open an M&P-10, take a quick look and reject it out of hand because of the MIM parts. Too bad for them; they’ll miss out on a fine rifle. If they do that to you, try to be polite when you snatch back your M&P-10.

To test, I clearly had to put some kind of sighting system on it, so I grabbed my trusty test scope, a Leupold 3-9 MR/T in a LaRue quick-attach/detach mount and clamped it on. From there, it was tested by running ammo over the chronograph, then doing some drills with the scope dialed down to minimum magnification, followed by accuracy testing from the bench.

The first thing you’ll probably wonder about is recoil. At a base weight of 7 3/4 pounds, the M&P-10 is not going to thump you more than other rifles. It will, however, make you pay for sloppy technique. A lot of shooters are accustomed to shooting an AR in 5.56 with what I call the “bazooka” hold. That is, they lift it as high as possible and only allow the toe of the stock to touch their shoulder. Do that with the M&P-10 (or any .308 rifle of this type) and you’ll do it just once. It will hurt. Shoulder it like any other .308 and you’ll be fine.

My range day was heavily overcast, but I did not notice any flash from the muzzle blast, except for the military surplus load, a West German batch dated from 1993. Even then, it was minimal. All loads ran just fine, but do keep in mind that the Stoner system can be sensitive to powder burn rate.

As for accuracy, the S&W M&P-10 is the latest to test my resistance to my adherence to rule number one for gunwriters: Ship it back. Accuracy like this is difficult to resist. While it shot very well indeed with all the loads, the one that this one favors above all is Winchester Supreme 168-grain boattail hollowpoint. I’d have to close my eyes and slap the trigger to get this rifle to shoot that load over one MOA. I can’t guarantee yours will do as well with this load, but this is spectacular shooting for what amounts to a .308 carbine. The mil-surp DAG 93 is nonreloadable and suitable for close-range practice. Starting with the correct twist is part of accuracy, and the 5R rifling is another. S&W has been making barrels for a long time; they know their business.

Applications and Aftermarket Possibilities
What future use is there for this rifle? I see a couple of paths for a prospective M&P-10 purchaser. The first is as a deer rifle, as-is. When I was a full-time gunsmith, a lot of my late-summer and early-fall work was in hosing the gunk (and wire-wheeling the rust) out of the gas systems of various self-loading deer rifles. I had to do it because getting in that deep was something the owners could not do, not having the necessary specialized wrenches and such. The M&P-10 is not prone to such rust. And taking it apart to clean out the gunk is an almost trivial mechanical task.

At the starting weight, all you need to do to make it a superb deer rifle (sorry, Pennsylvania hunters will have to observe from afar) is mount the scope of your choice, add a sling and a five-round magazine, and sight it in. Total weight won’t be over nine pounds, it won’t recoil very much, and you won’t have to worry about scratching fine wood while sitting in a hunting blind or still-hunting.

The second is as a base rifle for someone who wants a .308 but doesn’t want to spend a metric buttload of cash on a fully featured rifle when they’ll be changing a lot of the details anyway.

What would it take to make this a real thumper of a tactical/defensive rifle? Well, here’s what I’d do. Off comes the flash hider. On goes a suppressor mount/flash hider combo. The gas block gets swapped for one with a folding front sight built in. The handguards come off to be replaced with a railed free-float handguard. The upper gets a folding rear sight and optics of some kind. And the stock and pistol grip get changed.

I like pistol grips’ trim, so I’d go with a Magpul MOE-K. If I were building it as a handy carbine, I’d want a stock to keep it light and compact. If I were building it as a long-range rifle, that stock would be adjustable. And my choice of optic would match the stock type and the rifle’s intended role.

Why go to all that work? Cost and options. No matter what’s already on it, if you buy a fully featured rifle you’ll be changing something. Why not just build up with the items you want? Plus, by mixing and matching on your own, you’ll probably end up with a rifle that has cost you less in the long run.

But I suspect a lot of new M&P-10 owners won’t be changing nearly as much as I would. I’d bet that a range survey will turn up S&W M&P-10 rifles with just a sling, a scope (red dot or magnifying) and a bag or box full of magazines nearby. Which is just fine, because the owners will not be disappointed.


The M&P-10 makes a serious deer rifle, as InterMedia Online Hunting Editor Eric Conn found out on an Oklahoma whitetail hunt.

Find out about the price and availability of the firearm covered in this article at, where you will gain instant access to the inventory of Davidson’s Inc., one of the nation’s largest factory-authorized firearm wholesalers. customers know instantly if the firearm is available and can select from offers presented by dealers in their area. The selected dealer then immediately ships the firearm via Federal Express. Perhaps best of all, guns purchased at are covered by Davidson’s Guaranteed Lifetime Replacement Program. Fast. Easy. Hassle-free.

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