in use, the low-light diopter is stored inside the pistol grip cavity, with two blister packets of weapon grease. The useful life expectancy of tritium-illuminated night sight inserts is roughly 7-10 years. According to the Swiss Army, the 50% windage and elevation dispersion shot at 300 m from a machine rest averages 6 cm (2.4 in). The employed circular error probable method cannot be converted and is not comparable to US military methods for determining rifle accuracy. When the R50 results are doubled the hit probability increases to 93.7%. For anti-personnel use, the Stgw. 57 typical maximum range for consistent accuracy is . For designated marksman use, some special variants of the Stgw. 57 can be equipped with a quick-detachable Kern & Co Aarau 4×24 telescopic sight. The sight weighs and includes a variety of features, such as a Bullet Drop Compensation (BDC) elevation adjustment knob for ranges from 100 to 800 m, a tritium-illuminated reticle that enables target acquisition in low-light conditions and a diopter eyesight correction adjustment. Included with the sight is a lens hood with additional protective lens and a gray filter for glare reduction. A night vision sight with an infrared light can also be mounted. The Chilean version can fit a German-made Supra 4×24 telescopic sight. Accessories The Stgw. 57 is fed from curved detachable box magazines, made from aluminum and containing 24 rounds weighing empty and fully loaded. Special silver-colored magazines that can contain 6 grenade-launching cartridges (Gw. Treib.-Pat. 44) for use with rifle grenades weigh empty and fully loaded. The Stgw. PE-57 had 6-round magazines available as well. Magazines with 20-round capacities for the SG 510-4 in 7.62 NATO and 30-round originally for the Lmg. 25 may operate in the Stgw. 57 as well. Other accessories include a leather sling, a bayonet, various magazine pouches, cavalry holsters, and fortress-firing kits. Rocket-boosted rifle grenades can be launched with the use of the aforementioned silver-colored magazine. Grenade-launching cartridges enable the Stgw. 57 to fire Gewehrgranaten 58 rifle grenades which weigh depending on the warhead type. These rifle grenades achieve a muzzle velocity of and a maximum range of without the help of a booster charge or a V7 of and a maximum range of with the help of a booster charge. Rifle grenade variants include: Gw. HPz. G. 58: Hollow charge for heavy armor (direct-fire only), rated for ca. 280-320mm of penetration in rolled homogenous