12.7×40mm (Hyper Zergling)

{|style="width:100%; color:#FFF;"
|valign="top" style="padding:5px;"|
The 12.7×40mm is a rimless straight-walled large handgun cartridge designed for use in of pistols.
==History==
==Military cartridge variants==
===M225 semi-armor-piercing high-explosive===
The round is the standard-issue load for the chambered in the 12.7×40mm cartridge. Each of these rounds is nickel-plated and possesses a fuse at the tip, a high-explosive compound just behind the fuze, and a tungsten alloy penetrator just behind the explosive. Upon impact, the fuse detonates the explosive, which "blasts a path" for the tungsten alloy core penetrate the armor of the intended target. The M225 was tested on 10% ballistic gelatin behind from a distance of 90 meters (98 yards) from an , an and an . On average, the M225 rounds fired from each pistol penetrated 33 cm (13 in), 38 cm (15 in) and 30 cm (12 in), respectively into the ballistics gel. Each M225 bullet is labeled with a yellow-painted tip.
===M228 semi-armor-piercing high-penetration===
The M228 SAP-HP-T bullet weighs 14.3 grams (220 grains), is made almost entirely of phosphor bronze, is machined to have a fluted nose geometry. The fluted nose geometry aids the round in penetration and also allows it to hydraulically disrupt organic tissue. The M228 was specifically designed for the and when tested on 10% ballistics gel behind 63 mm of titanium alloy from a distance of 90 meters, it had an average penetration depth of 28 cm (11 inches).
===M231 subsonic===
The M231 Subsonic round weighs 47 grams (730 grains) and possesses a copper jacket with a tungsten core. As its name implies, travels below the speed of sound and does not produce a sonic "crack" when fired, making it ideal for firearms. Due to its low velocity, the M231 cannot penetrate most forms of body armor but can cause severe bruising and even break bones of an individual wearing light armor. In order for the M231 round to cycle reliably, a lighter recoil spring akin to those used in civilian pistols must be used for the lower-pressure subsonic load.
===M232 tactical training round===
The M232 weighs 2.3 grams (36 grains) and consists of a polymer shell holding a powerful liquid anesthetic that also has the ability to immobilize the nano-fibers woven into military training clothes, causing them to harden. The M232 is subsonic and was designed specifically for combat simulation training. Due to the M232's substantially lesser energy than non-training ammunition, a special training slide must be used in the pistol to allow for proper cycling.
===M233 stun round===
The M232 weighs 2.7 grams (42 grains) and consists of a less-lethal rubber projectile. Like the M232, the M233 is subsonic and was designed specifically for combat simulation training. Due to the M233's substantially lesser energy than non-training ammunition, a special training slide must be used in the pistol to allow for proper cycling.
===M330 high-explosive dual-purpose===
===M398 high-explosive squash head tracer===
The M398 HESH-T round possesses a copper jacket with an inert filling at the tip, a plastic explosive that takes up most of the body, a fuse, and a tracer element at the base. When the cartridge is fired, the tracer ignites, leaving behind a visible orange trail. Upon impact, the round is "squashed" against the target, and milliseconds later, the fuse detonates the explosive filling, stunning or disorienting the target with concussive force, should he/she/it survive the shot. The M398 is able to fully penetrate the of and the with variable consistency, but would be completely stopped by the outer shells of either exoskeleton. Due to the niche purpose it serves, the M398 is warranted to relatively limited use in the UNSC Defense Force. Each M398 round is labeled with a white-over-red-painted tip.
===M630 armor-piercing===
The M630 AP round weighs 32 grams (500 grains) and possesses a copper jacket with a depleted uranium core. It was designed specifically to be used in the and was tested to be able to penetrate on-average 33 cm (13 in) into 10% ballstics gel after passing through 63 mm of titanium alloy from a distance of 90 meters. Each M630 bullet is labeled with a black painted tip.