The HG 85 (Hand Granate M1985) is a round fragmentation hand grenade designed for the Swiss Armed Forces and still produced by RUAG Ammotec in Switzerland. HG 85 is the internal designation of the Swiss Army and replaces the HG 43 from WWII.
On detonation the steel body, containing 155g TNT, releases around 1800 fragments weighing on average 0.1 grammes. UK grenade range safety data suggests the L109 - and by extension all live versions - may represent a danger at ranges up to 200m. Intended for use mainly when fighting in built-up areas, trench clearing, and wood clearing, it is effective against unprotected personnel up to 10 m (33 ft) away, and protected personnel up to 5 m (16 ft).
The grenade is spherical with a bushing on the top threaded internally to accept the DM 82 CH fuze mechanism. Due to its specially constructed fuze and packaging, the grenade is considered very secure. It is designed to be effective against opponents wearing body armour, up to 20 layers of Kevlar and 1.6mm of titanium.
A supplementary spring steel safety clip is clipped over the safety lever and bushing on top of the grenade preventing the safety lever from moving.
In September 2000 a six-year contract with Swiss Ammunition Enterprise Corporation (a RUAG subsidiary) was announced, committing the UK to purchased circa 363,000 grenades for combat and live training, first deliveries scheduled for March 2001.
The L109 is the British designation for the HG 85. It differs from the HG 85 in that it has a special safety clip (matte black in colour, which is similar to the safety clip on the American M67 grenade.
The L109 is deep bronze green in colour with golden yellow stencilling, and a rough exterior comparable to light sandpaper, and a yellow band around the top bushing, and weighs 465gm. Markings give the designation "GREN HAND HE L109A1", a manufacturer marking "SM" meaning "Swiss Munitions", and a lot number. (Markings on the safety lever give the designation and lot number of the fuze.)
Once the safety pin is pulled, the grenade is live but so long as the fly-off lever ("spoon") is kept depressed while the grenade is held (and the grenade can be held indefinitely with the pin out) it can be safely returned to storage so long as the fly-off safety lever is still in the closed position and the safety pin reinserted. However, if thrown - or the lever allowed to rise - the protective plastic cover falls away and the striker, under pressure of the striker spring, begins to rotate on its axis. This causes the safety lever to be thrown clear, the striker continues to rotate until it hits the percussion cap, which fires and ignites the delay pellet. The heat of the burning delay pellet melts solder holding a retaining ring, allowing the detonator to move under the influence of a spring from the safe to armed position. The delay pellet continues to burn and after between 3 and 4 seconds burns out and produces a flash that forces aside a flap valve allowing ignition. When the flash reaches the detonator this initiates a booster charge which in turn initiates the main explosive filling.
The L110 (Drill Grenade) is an entirely inert (no explosive content) version of the L109.
Identical in size, weight and shape, as the live grenade and is used for training purposes, specifically correct handling and throwing. It can be easily distinguished from the live grenade as it is dark blue with white markings  (see below).
The body is solid aluminium with a textured plastic coating made in the same form as the live grenade, the textured coating ensuring a good gripping surface. A hole drilled up from the bottom indicates an empty store as well as ensuring the drill grenade is of the same weight as a live grenade. A bushing on top of the grenade has a dummy fuze mechanism permanently attached with a slot for the pull ring to clip into to prevent it being accidentally pulled. The fuze mechanism, under the plastic cover is very similar in appearance to the American fuze mechanisms. Internally there is an extension on the striker to allow it to be re-cocked during training and there is a leaf spring safety that clips around the safety lever and neck of the grenade preventing the lever from rotating even if the safety pin is pulled.
The markings are 'GREN HAND INERT DRILL L110A1' and a manufacturers marking "SM" meaning Swiss Munitions. The fuze mechanism is marked on the wide bottom portion of the lever "HG2 DM 82 CH".
This practice grenade has a small simulation charge (flash/bang) that imitates a live grenade for training purposes. It is distinguishable from the wholly inert L110 by being a much lighter blue and is fitted with a distinctive gold/orange plastic cap and safety lever.
The body of the L111A1 is made of steel and is covered in a textured plastic material with and has the word 'PRACTICE' embossed near the top of the body, near a top portion is larger than the bushing on the live grenade. Like the L110 there is a large aperture in the bottom of the grenade which demonstrates it is not a live grenade but in the L111A this aperture allow gas from the practice fuze to escape. Consisting of two parts, a grey reusable striker mechanism and an L162 practice fuze (which has a blue body with a brown base and is fitted with a silver washer) the practice fuze is fitted into the bottom of the reusable striker mechanism then the entire assembly is screwed into the top of the grenade. In this version the safety lever is attached by a plastic strap to prevent loss, the entire unit, apart from the expended L162 practice fuze, being reused.
Markings, again in white, include 'GREN HAND PRAC L111A1', a manufacturers mark 'SM' meaning Swiss Munitions, and a lot number.
The Nr300 is the Dutch designation for the HG 85. It is exactly like the L109.
HG 85 entered service in the Swiss Army in 1985. It is also used in a number of other European armies and armies in the Middle and Far East.