HQS Slim Sound Moderator

HQS has developed a range of lightweight, yet strong, muzzle and over-the-barrel moderators from scratch. The Hunter and Slim models are for the commonly used hunting calibres, while the Special models cover the magnum calibres.
On test today is the HQS Slim, which is the small brother to the HQS Hunter. It has a similar single-core construction but with a reduced diameter. The Slim was designed for maximum suppression for the size (30 dB reduction without affecting the balance of the rifle).

Spec

These moderators are all made on the latest generation CNC machines and out of aircraft-grade aluminium. They are finished on fully automated electrolytic anodising machines.
‍The Slim is a well-made mod and as its name suggests, it is compact, showing a 40mm diameter and 250mm length. Plus, it only weighs 293-grams. Being an over-the-barrel design, it only increases the length of the rifle by 154mm.
The HQS mods are calibre specific, with .223, .264, .30 and 9mm available for this Slim version. I had a .30 cal with a 5/8 UNEF thread, although 13х1, 14х1, 15х1, 16х1, 17х1, 18х1, 1/2” – 20 UNF, and 1/2” – 28 UNEF are also available.

Closer look

If you look at the back of the mod, the threaded section looks to be removable, indicated by two slotted grooves, but it does not say that in the literature. The Slim, however, is strippable for cleaning and comes with a very good spanner. Just pop this spanner with two spigots into the associated holes and turn it so that the Slim disassembles into two parts - the outer sleeve and an inner one-piece machined core section. This inner core is interesting as it is riddled with holes and vents to redirect the hot expanding gases.
The rear 4.5” is the part over the barrel, and it acts as a secondary cooling chamber, whilst most of the gases are swirled around the labyrinth of 11 chambers pierced with four vents per section. Looking closely at the rear section, there are three Allen screws, so it does come off. You also have an O-ring at the top and bottom of the inner core that seals the unit. You get two spares and some grease to prevent the aluminium from galling.

In the field

I fired around 155 rounds during testing, with no leaks around the inner or outer core. Although it balanced well on the rifle I was using, bear in mind that the rear aperture is only 23mm in diameter, so large varmint diameter barrels may not fit.
You have a very tough satin black anodized finish and the whole moderator was very well built. Also, it looked far less obvious on a rifle than some large cans I have tested.
Fitted to the Seekins in .308 Win, the muzzle report was well suppressed for such a slim moderator. This is probably due to the length, which compensates for the lack of girth. It sounded very stifled and had little or no roll-on echo when shooting over open fields or glens

Conclusions

Overall, I have been very impressed with both the noise reduction and build quality of this new sound moderator, and I look forward to testing others in the HQS lineup.