Dead air sandman because it's quiet, that's why.
The Sandman series comprise a pair of .308 suppressors, but with a bunch of differences.
First, they are "all centerfire" rifle suppressors. You can use them from 5.56 up to .300 Win Mag, with no barrel length restrictions. Which means that you can park a Sandman on your 5.56 SBR, and not worry about the uncorking pressures bulging your can. I can't imagine someone having an SBR in .300 Win mag, but if you do, then the Sandman is the can for that. Just be sure if you are shooting it without the suppressor, you go down to the other end of the firing line and play by yourself.
The baffles are stellite, but they are welded into a solid core--a welded monocore if you will--for rigidity and durability.
The front cap is removable. This gives you a couple of options, and also a hedge against accidents. You can go with a plain front cap, or one with a built-in flash hider. And, if you should happen to damage your front cap (Dead Air speaks of droppage, but I think what we're all thinking; baffle glance) then you can unscrew the front cap, install a new one, and continue on.
The mounting system is also a bit different.
You have a choice of two mounts; the included muzzle brake, which works well, as a brake when the can isn't on your rifle. The same size flash hider, which is a three-tine open-end hider. Now, if you happen to have the flash hider on your rifle, and you want to get a muzzle brake function out of it, you mount the Pyro Enhanced muzzle brake onto the flash hider muzzle device, and you get a brake effect. That strikes me as the long way around, but for those who want a hider until they want a brake, here you go.
The muzzle brake comes in two thread pitches, 1/2x28 and 5/8x24, the obvious 5.56 and .308 threads. The flash hider comes in three; those same two, plus the metric M15x1. This means if you have a rifle with weenie Euro-threads on it, you have an option. The mounts are made of 17-4 stainless steel, and nitride for surface hardness and durability.
The mounting system is a bit different. Inside the rear cap are three claw-shaped locking hooks. To mount the suppressor, you line up the groove in the rear collar of the suppressor itself with the top-center groove on the mount. Then you turn the suppressor, not the rear cap. Turning the suppressor compresses the wafer springs in the rear cap, and cams the hooks onto the rear face of the mount. Meanwhile, the interior of the rear cap has ridden over the coned bearing surface of the muzzle device.
The effect is to self-center on the cone, provide a large bearing surface, and lock the suppressor to the mount in a way that does not introduce lateral or rotational torsion to the system. It does take some getting used to if you've spent a lot of time with suppressors that lock by turning the rear cap.
The Sandman comes in two sizes, the S and the L. the apparent difference is simple; the L is longer. However, the difference is more than that. The L, while being longer and a bit heavier, provides more volume and mass for sound reduction and heat absorption. Dead Air reports that while firing standard 7.62 ammunition, the Sandman L produces a 31 dB sound reduction. That would bring the usual 165 dB or so sound signature down to hearing-safe levels. Yowza!
The S doesn't provide as much sound reduction--it can't--but for those running a suppressor on a .300 Blackout SBR, the just over two inches less length is more to be sought than a couple of dB reduction.
Mounting the cans was easy. Each comes with a set of flat washers and the muzzle brake mount. I checked the thickness of washers I'd need to get the muzzle brake to torque up top dead center, then degreased, Rocksett, screwed on and tightened, and left it alone overnight.
The rifle I used was a Wilson Combat 7.62. It has proven itself a tack-driver, and so I figured it would be a good test bed. Also, because it was already zeroed, I'd get a chance to check if there was a zero shift with the Sandman S or L on.
The ammo was Black Hills 168-grain BTHP, which has a sub-MOA track record.
First up, check the zero with the muzzle brake on, but no suppressor. Spot-on. Then install the Sandman S, followed by the Sandman L. No change in zero, or at least none that can be attributed to the suppressor. I find that I by myself can induce a quarter to half MOA shift in zero at 100 yards, just by sitting differently at the bench. I have to share the range with the rest of the club members, so I can't build a "just for the gun writer" bench and chair, to be used solely HR by me. I have found that while the groups wander a faction or so, they stay the same size regardless of the quarter-MOA wandering.
I then tried it offhand, banging the steel, with and without the suppressors. The muzzle brake works quite well as a brake. It isn't the most softy-shooting brake I've ever used, but then again, the ones that work better are closer in size to a soft drink can, than the compact brake Dead Air makes.
The brake is a brake when it comes to noise. You don't want to be shooting it under a roof, or indoors. But the suppressors? Oh, nicely quiet. My range is ringed by berms, and tall trees, so I always get a lot of supersonic echo back at me, but once I got over that (it's always an adjustment) the Sandman both S and L were quiet.
Putting on a suppressor is no big deal. Getting one off when it is hot, is. However, the rear cap and the body are both going to be hot, so grabbing a hot suppressor is grabbing a hot suppressor. If you're going to be taking off a Sandman, S or L, or any rifle suppressors, when it is hot, you'd better have an oven mitt in your gear bag.
Once the Sandmen were each cool, I went to take them off, and found the system works well even when there's carbon buildup. The latching hooks don't have to grind through burnt-on carbon, and the coned surface releases easily once you start to pull.
I can see getting a Sandman, L or S, and then investing in a fistful of mounts. There'd be one for each of your 5.56s; rifle, carbine and SBR. Then you'd want mounts on your various .308 rifles, both self-loaders and bolt guns. And finally, for your long-range tack-driver, a mount on the .300 Win Mag bolt gun.
But which size? Hmm. I'd say, if your needs or desires have you down in the shorter lengths, the 5.56 SBR, a .308 carbine, then the Sandman S would be the ticket. If, on the other hand, your focus is all on big-bore, and long range, then go with the Sandman L. After all, if you are hauling a 20-inch .308 self-loader, or a .300 Win mag with 20-, 22- or 24-inch barrel, the extra couple of inches of suppressor are hardly noticeable, and well worth the extra dB reduction.
Regardless, you're going to be getting a hell of a deal.
DEAR AIR SANDMAN-S OAL 6.8" Net Length Added 5.5" to Firearm Diameter 1.5" Material 17-4 PH & 316 stainless Weight 18.5 oz Finish Cerakote Black Calibers Available Up to .300 Win Mag Full-Auto Rated Yes Mount System Dead Air brakes or flash available hider (muzzle brake mount included) MSRP $1,049 DEAR AIR SANDMAN-L OAL 8.9" Net Length Added 6.75" to Firearm Diameter 1.5" Material 17-4 PH & 316 stainless Weight 21.8 oz Finish Cerakote Black Calibers Available Up to .300 Win Mag Full-Auto Rated Yes Mount System Dead Air brakes or flash available hider (muzzle brake mount included) MSRP $1,199