The AWM (Arctic Warfare Magnum) is a sniper rifle manufactured by Accuracy International. It is also known as the AWSM (Arctic Warfare Super Magnum) (usually meaning the .338 Lapua Magnum chambered version).
The AWM rifle is a variant of the British Accuracy International Arctic Warfare (AW). Compared to the AW, the AWM has a longer bolt to accommodate larger magnum-length cartridges such as the .300 Winchester Magnum and the .338 Lapua Magnum.
The AWM features a detachable box magazine which holds five rounds. The normal cartridges for this rifle, and the ones which have been accepted by NATO for use in AWM rifles, are .300 Winchester Magnum and .338 Lapua Magnum.
Normally, the AWMs are outfitted with a Schmidt & Bender PM II 10x42 telescopic sight with 10x fixed power of magnification. However, a Schmidt & Bender PM II with variable magnification of either 3-12x50, 4-16x50 or 5-25x56 can be used if the operator wants more flexibility to shoot at varying ranges, or when a wide field of view is required. Accuracy International actively promotes fitting the German made Schmidt & Bender PM II product line as sighting components on their rifles, which is almost unique for a rifle manufacturer. The German and Russian Army preferred a telescopic sight made by Zeiss over Accuracy Internationals preference.
The AWM rifle is normally supplied in a metal transit case together with scope, mount, butt spacers, bipod, spare magazines, sling, cleaning and tool kits.
The AWM chambered for the .300 Winchester Magnum is fitted with a fluted, stainless steel barrel that is 660 mm (26") long for optimum velocity and nominal weight.
The AWM in the .338 Lapua Magnum calibre was designed as a dedicated long range sniper rifle combining the manoeuvrability of rifles chambered in 7.62 x 51 mm NATO with the greater power and range of the .50 BMG cartridge.
Compared to most .50 calibre rifles, the AWSM offers considerably less rifle weight, recoil, muzzle flash, smoke and report. Although the .338 Lapua Magnum delivers less energy to the target compared with the .50 BMG, both cartridges have similar trajectories, resistance to wind drift and penetration, while the .338 Lapua Magnum unquestionably outperforms the 7.62 x 51 mm NATO, especially at ranges beyond 800 m. AWSM rifles in .338 Lapua Magnum can also be deployed against unarmoured hard targets, including armoured glass.
The AWSM is fitted with a stainless steel, fluted, 686 mm (27") barrel, which research has found to be the best compromise between velocity and precision on the one hand, and weight and length on the other. A non-traditional 279.4 mm (1 in 11 inch) right-hand twist rate was selected to optimize the rifle for firing 16.2 up to 19.44 gram (250 up to 300 grain) .338-calibre very-low-drag bullets. Whether this twist rate is adequate to stabilize 19.44 gram gram (300 grain) very-low-drag bullets in dense air encountered in Arctic sea level environments is questionable. The bullet manufacturer Sierra advises a tighter 254 mm (1 in 10 inch) twist rate for its 19.44 gram (300 grain) .338-calibre HPBT MatchKing bullet.
A problem with AWSM rifles is that .338 Lapua Magnum cartridges loaded to the C.I.P. (Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives) maximum allowed overall length of 93.50 mm (3.681 in) do not function properly due to a lack of internal magazine length. The reason for this problem is that the AWSM bolt-action is not specifically designed for the fat and long .338 Lapua Magnum cartridge. Because of this, ammunition manufacturers produce .338 Lapua Magnum cartridges that are loaded short enough (≈ 91.44 mm (3.600 in)) to fit in the AWSM magazines. As long as .338 Lapua Magnum cartridges that will fit in the magazines are used, the AWSM rifles can be used as repeating rifles instead of single shot rifles. Ammunition types currently (2007) available for the .338 Lapua Magnum are FMJ, hollow point, Armour Piercing (AP) and Armour Piercing Incendiary (API).
The British Armed Forces adopted the AWSM rifle chambered in .338 Lapua Magnum as the L115A1 Long Range Rifle. The British L115A1 rifles are outfitted with Schmidt & Bender 3-12x50 PM II telescopic sights. The L115A1 is currently (2007) in service with the Royal Marines, British Army and RAF Regiment in Afghanistan and Iraq.
In November 2007 the British Ministry of Defence (MOD) announced that their snipers in the Army, Royal Marines and RAF Regiment are to get a new rifle. Accuracy International will supply 580 L115A3 Long Range Rifles with day telescopic sights. The L115A3 is being supplied as part of a broader Sniper System Improvement (SSI) program which also includes night sights, spotting scopes, laser range finders and tripods. The L115A3 rifle is due to be ready for operational use in the spring of 2008. The upgrade over the L115A1 comprises mounting:
The MOD claims a muzzle velocity of 936 m/s (3071 ft/s) for the L115A3. This implies the British military are using a high pressure load to attain this muzzle velocity. A reverse engineering simulation with QuickLOAD internal ballistic software predicted that a typical military .338 Lapua Magnum load using Lapua LockBase B408 bullets at an overall cartridge length of 91.44 mm (3.600 in) produces ≈ 460 MPa (66833 psi) maximum piezo chamber pressure to achieve the claimed 936 m/s (3071 ft/s) muzzle velocity.
Since 1998 the Bundeswehr fields an AWM-F chambered in .300 Winchester Magnum (7.62 x 67 mm in Bundeswehr nomenclature), with a 3-12x56 SSG telescopic sight made by the German company Zeiss, under the designation of G22 (for Gewehr 22) or Scharfschützengewehr 22 (sniper rifle 22). The German G22 rifles have folding stocks and emergency iron sights. For their G22 rifles the Bundeswehr claims an effective range of 1,100 m.
The German ammunition manufacturer Metallwerk Elisenhütte Nassau (MEN) has specially developed 7.62 x 67 mm ammunition for the G22.
The Carl Zeiss Optronics telescopic sight has a mil-dot reticle and a scale that enables the operator to see the dialled in elevation setting through the rifle scopes ocular. The Bundeswehr 3-12x56 SSG telescopic sight differs somewhat from the further developed 3-12x56 SSG-P telescopic sight depicted in the Zeiss brochure. The Bundeswehr telescopic sight has no parallax setting option and the range scale has a setting range from 0 to 10 instead of 0 to 11 symbolizing the 11.2 milliradian elevation adjustment range shown in the current (2006) Carl Zeiss Optronics 3-12x56 SSG-P telescopic sight brochure.