HM Defense Stealth MS5 Review: Integrally Suppressed AR

Images by the author unless otherwise noted

First off, I am no prophet. I cannot know what will happen in the world of firearms, but I can guess. Let’s talk about suppressors specifically.

When considering suppressors and integrally suppressed firearms, my guess is that sales will go – if they haven’t already – through the roof. This has been borne out recently by sales figures and ATF form approvals topping 150K. I guess my prophecy was correct. And, I think we all know why… the “Big Beautiful Bill”. That piece of legislation did many things, but one thing of interest to shooters is that it did away with the extra $200 tax you had to pay in order to buy a suppressor, or an integrally-suppressed gun, and other restricted firearms. 

This, as I’m sure most readers know, became effective January 1 of this year. I can imagine that NFA dealers are having to pack their lunches because they don’t have time to go out, with people beating down their doors to buy these items.

It was with the dropping of the $200 fee in mind that I spoke with my contact at Ohio-based HM Defense, Clay, about the possibility of getting one of their suppressed ARs to review. These are the guns regularly selected by law enforcement and military units. I recently reviewed two of them: their .50BMG and their Defender M5L 5.56mm AR. 

They are well-made, and their AR has two newly-patented design features: an integral, machined-with-the-barrel gas block, and what they call their HMB bolt, a stronger version with the cam pin sitting in a well in the bolt. The hole doesn’t go all the way through… traditional bolts can fracture at the sides of the pin hole, but with a “bottom” to it, HMB bolts tend to be stronger. I explained both of those features in the above AR review: suffice it to say that they are also present on the newest gun from HM Defense to be reviewed here, their Stealth MS5 suppressed AR. Go here to read what HM Defense has to say about this rifle.

images:hmdefense.com

The Professional’s Choice

In terms of professional adoption, I was struck by how many times professionals in the military and law enforcement choose HM Defense products. Here are a few images, provided by HM Defense…

A lefty, like me!  That’s about all we have in common, I’m afraid…

We see that these rifles are popular with those whose lives depend on a reliable firearm. I learned a couple of things by studying these photos… first, optics. Three photos show what appears to be a low-power variable optic scope (LPVO, 1-8×28 in one photo), while in the top photo, a red dot is in place along with what may be a magnifier towards the muzzle. Also, three photos show transparent magazines, so you can tell at a glance when to stick in a fresh one. I’m still learning… photos can be very informative.

Two In One

Back to the rifle at hand, the MS5 (above). 

Talking about suppressed ARs, there are two ways to acquire one. The “normal” way is to buy an AR and a suppressor, unscrew the flash hider, and screw on the suppressor. Or, you can just cut to the chase and buy one with an integrally suppressed barrel. HM Defense was the first company to make such a thing, according to their website.

Integrally-Suppressed AR Advantages

What are some advantages of this built-in suppressed MS5 over adding a separate suppressor to your AR? The first one that comes to mind is overall length. This suppressed 5.56, with suppressor, is about as long as a plain-jane AR minus a can. So, you won’t be bouncing the barrel off obstacles.

My second point has to do with installation. Even though they just screw on, there is still a bit of a learning curve when you add a suppressor to an AR. Also, another thing to think about is the gas situation. Some cans can create an issue, and you have to re-figure out which spring and buffer weights will work best. With this rifle, you pull it out of the box, load it, and shoot it. There is no tuning required, as everything is designed to work together from the get-go. 

Another point has to do with suppressors going off-track, so to speak. It doesn’t happen often, but sometimes a can gets out of alignment for whatever reason, and you have a baffle strike. Since this one is machined with the barrel, that can’t happen.

One more thought – with the new law in place, you automatically save the $200 tax plus the cost of a separate suppressor when you buy this rifle, as you get a rifle and a suppressor in one package and one sale. The rifle’s MSRP of $1995 is not out of line with other, top-line non-suppressed ARs, and when you figure you’re getting a suppressor plus a quality rifle for one price, it becomes attractive.

Is the can effective? That is a “duh” question. Of course it is.

Note the “Peak” measurement of 118.2 DB. A non-suppressed AR hits 160-170 DB. That’s louder than a jet taking off, which is usually 130-150 DB. I mention elsewhere in this review that you should still wear hearing protection when shooting this rifle, but with my hearing aids off, I was able to shoot it bare-eared. It’s about as loud as a .22 rifle at 120 DB. 

You also have the advantage of not having to tune the rifle and the suppressor to work together, as you must do when you buy one that screws on. This rifle is built from the ground up with the suppressor attached. We already looked at the advantages of doing that.

Hearing Protectors Required?

I mentioned hearing protection. What about that? Should you wear protection? In a word, yes. However, I’m a unique case in that I wear hearing aids – too much unprotected shooting and rock ‘n’ roll in my misspent youth – and I simply pulled the volumes down to zero when I shot. I was able to not have to wear hearing protectors since I already had plugs in my ear canals, but I recommend that “normal” ears out there be protected. I will state that, if I have a prolonged shooting session, I will stick a pair of protectors on. No sense in borrowing trouble, as my dear granny used to say.

One benefit of shooting suppressed that needs to be mentioned is the psychological factor. Shooters, especially new ones, tend to jump when the gun goes off. This is especially true if they are not wearing hearing protection. A built-in flinch can be caused by the noise of a gun firing. Shooting suppressed takes that factor away, especially if you are wearing hearing protection. Think about how shooting a .22 rifle causes no flinching… it just isn’t that loud. 

The Rifle

Let’s look at the Stealth MS5. First, here are some specifications and features.

I usually just do a listing of such things, but the website shows them in a different format. Since this is such a unique rifle, let’s use images from the HM Defense website that have some interesting information. There’s a list below.

Here are some features of this unique rifle…

1. Patented 16.25-inch Monobloc barrel with integral suppressor and patented HMB bolt.
2. Compact SBR-length rifle, but no SBR stamp is needed.
3. Free-floated Monobloc barrel.
4. Barrel and suppressor are machined from one piece of steel.
5. The gas block and suppressor require no pinning or welding; they are machined with the barrel.
6. Improved harmonics and accuracy.
7. There are no suppressor adapters to install, with attendant gunsmithing fees.
8. The suppressor cannot come loose, so no baffle strikes by bullets
9. No tolerance stacking of threaded barrels and devices.
10. No liability is commonly associated with conventional threaded-on suppressors.
11. This rifle is the choice of LE agencies looking to mitigate suppressor liabilities.
12. No separate cleaning of the suppressor is needed – just follow HM Defense instructions for cleaning the bore.
13. The suppressor is serviceable if required (I was told that, to date, they haven’t had to service one of them).
14. Trigger pull weight: avg. 6 pounds, even, as tested with my Wheeler digital gauge

The HM Monobloc Integrally Suppressed barrel eliminates the hassles associated with installing and maintaining a threaded-on suppressor adaptor and suppressor. It eliminates the risks and liabilities associated with all threaded-on suppressors. 

In terms of actual rifled barrel length, the HM Defense Stealth MS5 features a 9-inch barrel. Add in the integral suppressor, and you have a total length of 16.25 inches. This 16-plus-inch overall length makes it a non-NFA (National Firearms Act) item. The barrel and suppressor are machined from 4150 Chromoly steel for enhanced rigidity and accuracy. Also, HM Defense rifles are button-rifled… I’ve never had a problem with accuracy with the Defender M556L. One more point that was mentioned above is that the gas block is machined with the barrel, so you don’t have to worry about it working loose.

Subsonic Ammo Or Not?

Subsonic loads have been recommended for this rifle. I didn’t have any on hand, so I went with regular-pressure 5.56. The reloader in me wanted to try putting together some subloads, but I didn’t have the chance with the way the weather is in my unheated pole barn. Look for more on 5.56 subloads with Tite Group powder in the future. That ought to be interesting!

Otherwise, my advice is that if you want to try subsonic loads in calibers not originally designed for them (such as the 5.56mm), you might want to buy factory ammo to do that. Other calibers, such as the .300 Blackout, are designed for subsonic loads, and there is plenty of reloading data available.   

I also wanted to put together some “regular” .223/5.56 loads, with the Varget, CFE223, and Winchester Sta-Ball Match powder that Hodgdon sent, but with the foot of snow and below-zero temps we have now, I’ll have to postpone that until I can comfortably use my loading bench, or do it in my son’s heated pole barn office. Stay tuned…

Photos:

I added a Bear Creek Arsenal red/green dot sight for this review. I have other optics coming, but this was the only rifle red dot I had at the time. With this sight,  I could at least shoot the rifle for the review. This sight works very well and holds zero, plus you have two colors to choose from. Not bad for the price… the link is below. I do imagine, however, that I’ll swap it out when I have the chance.

Clay at HM Defense stuck a BCM fore grip in the box, which I mounted. It does make the rifle easy to handle.

Also note the 20-round mag. The rifle comes with a 30-round magazine, but I prefer the shorter one for bench shooting or everyday use. It’s a good balance between the longer mag and the very short 10-rounder. I do see the advantage of a 10-round mag; here in Indiana, you can use an AR to hunt deer, but you are limited to 10 rounds. Show the game warden your 10-rounder, and you’re good to go, no questions.

Target Time

I am blessed to be provided ammo for my reviews from Black Hills – there’s a link below. After talking to my contact at HM Defense, he told me that standard-pressure ammo works best with the suppressor and gas system for this particular gun. Suppressors tend to make guns behave as if they were over-gassed. That’s something to consider, especially if you are thinking about shooting subsonic loads. 

I grabbed a couple of 5.56mm loads and moved to my backyard range to ventilate some paper targets. For funsies, we also shot at my Caldwell AR500 steel silhouette at 80 yards. Bear in mind that this rifle was conceived with CQB in mind – close-in – but it has no problem reaching out at longer ranges if needed.

The conditions were less than desirable at my backyard range, with a foot of snow and single-digit temps, but I stuck some targets out as far as I could get… about 35 yards. The rifle easily handled the two loads I tried:

Here are two sample targets, with the 62-grain on top and the 77-grain below it…

You won’t have any accuracy problems with this rifle. I did notice a drop in velocity, which makes sense since the barrel is shorter than the usual 16 inches. My Athlon Rangecraft Velocity Pro radar chrono indicated a loss of about 400 f.p.s. (average) between both loads. This is not a deal, as the rifle produces enough velocity and energy for the tasks it was designed to undertake. Neither of the loads had a velocity much under 2600 f.p.s.

Final Thoughts

I truly enjoyed doing this review. Not only did I get to shoot a very well-built AR, but it was quieter… two wins! The rifle itself is very accurate and reliable – no stoppages – and it didn’t lose a whole lot of velocity due to its shorter barrel. The patented bolt-and-monobloc construction added to the experience. Add in the fact that the suppressor helped make the sound less ear-shattering. You should still consider wearing hearing protectors, as this is not Hollywood, but it IS a lot quieter than an unsuppressed rifle.

Also, remember that you are getting both a rifle and a suppressor in one package. The fact that the $200 tax has gone away will help sell these, I’m betting. I can imagine that HM Defense has really ramped up production. If you are looking for a quieter way to enjoy an AR, you might want to check this rifle out. It also comes in .300 Blackout, if you’re a fan of that caliber. These integrally-suppressed solutions make sense. 

And here’s an interesting fact… There are more HM Defense models beyond the semi-auto versions. Once, when I contacted my guy at the factory, he said that he had a full-auto version on his desk at that time… those are for qualified agencies.

There is one last thing to consider when shooting a suppressed rifle such as this one, a good thing… you’d better have plenty of ammo handy! Dropping the decibel level is almost the same as shooting this rifle with a .22LR. You will want to just plain shoot for fun. I thought I’d better mention that. I’ll need to have a ton of 5.56 on hand when the weather breaks and our four sons come over to shoot! 

I thought I might add a little information here at the end about where I picked up this suppressed AR, and will pick up future suppressors, as more reviews are in the works. I discovered a local NFA dealer who provides great service and also happens to be an HM Defense dealer: Lucky Lab Armory. If you live in the Hoosier state, you can contact them at 812-554-0624. They can do all the paperwork online and then ship it to you. As of now, they are Indiana-only for remote sales. They have a great selection of suppressors and firearms at really good prices. Peyton will take care of you.

Links To Items Used In This Review 

• Athlon Rangecraft Velocity Pro Radar Chronograph, $500
• Bear Creek Arsenal-Branded Red/Green Dot Sight, $80
• Birchwood Casey Shooting Bags Filled, $40
• Birchwood Casey Eze-Scorer 8 Inch Bull’s-Eye Target, 26 Targets, $9
• Birchwood Casey Range Cleaning Kit, $60
• Black Hills Ammunition
• Caldwell AR-15 Magazine Charger, $55
• Caldwell 66% AR500 Steel Silhouette Target, $127
• Caldwell Ultimate Target Stand, $33
• GPS Medium Range Bag, $150 
• Real Avid Smart Drive Screwdriver 90 Bit Set, $110
• Walker Game Ear Firemax Active Hearing Protection, $160 
• Wheeler Firearm Accurizing Torque Wrench Kit, $88
• Wheeler Trigger Pull Gauge, $88
• Wheeler Red Laser Bore Sighter, $193 (available in green, also)