Suppressors get hot when used. They are basically specialized mufflers, similar in design to auto mufflers, which they actually predate. The principle is simple: an incremental bleeding of gases, rather than a quick release, dissipates the sound also.
If one looks at the photos, one will notice that a suppressor produces a little gas and backpressure. Left-handed users who didn’t invest in a left-handed Stag Arms upper will really notice this. The gas blows back at the shooter.
What mitigates the gas condition? First, the PRI (Precision Reflex Inc.) M84 Gas Buster Charging Handle is a good investment. I recommend the M84 Military Big Latch model. This product works well with any AR-15 product, let alone a suppressed one; I know some may suggest a piston upper. The piston advantage is interesting from an engineering standpoint, but there is nothing wrong with the inherent reliability of the impinged system.
Suppressors are not completely silent; one can expect to experience about a 30-35 decibel reduction out of a good 5.56-caliber product. The 35-decibel reduction from the YHM 3500s brought the noise down to a level that gives the intended tactical advantage for law enforcement officers: we could communicate while shooting.
Suppressors generally change the point of impact between when it is mounted and dismounted. This is simply a difference in the harmonic of the barrel with the extra weight and the placement of the weight. The best way to accommodate for this shift is to always shoot with the product mounted and treat it like an integral part of the carbine.
It is preferable to at least have a point of impact shift to be vertical, although I have seen some products shift horizontal. The YHM 3500 A shifted 1 foot at 50 yards with the suppressor off. Rock Anderson told me that he could totally live with that and proceeded to demonstrate target engagement, on or off. The accuracy was predictable, which is key here. I guess it didn’t hurt that this product was on a Noveske barrel.
How did the YHM 3500 A shoot? The balance of the added 20 ounces on the muzzle really improved the handling. Anderson recommended a 10.5-inch barrel length here, which worked for the carbine length gas system and this product.
The diameter of the product did not get in the way of optics and, most importantly, fit in standard diameter forends.
The YHM-3300-A has a new big brother, the YHM-3300-Ti, which is now a titanium product which offers 32db reduction. I found the YHM-300-A to be the perfect product for 30-caliber cartridges like the 300 Blackout.
Concentricity is critical in a QD mount, and the way to test it is to mount and dismount a suppressor, checking for point of impact shift. The YHM-3300A mounts solidly on the muzzle every time. The QD mount screws in, then ratchets when it reaches the torque limit. The ratchet is important. They get hot. A user with gloves (folks, you’ll forget gloves only once, I promise) will touch the hot can for only seconds at a time. This causes the user to not be able to estimate the amount they tighten the product, and can cause over-tightening.
YHM is one of my favorite AR-15 product manufacturers; they are well known for AR-15 replacement parts, and their complete upper and complete builds are top notch. I’ll add to that their suppressor systems are some of the best products I have ever tested.