Development of reliable weapons for troops on the ground is a pressing need for the world's armies.

Here are Popular Mechanics' choice of the five best ones, which include the Singapore-developed SAR-21.

1 SCAR-LIGHT
DEVELOPER: FNH USA (US) CALIBER: 5.56mm FEATURES: More accurate and less prone to jamming than the standard-issue M-16 and M4 rifles, the SCAR uses quick-change barrels that can be swopped using a minimal number of tools. PROGRESS: The manufacturer had initially expected the weapon to be deployed in 2006, but after a limited production run last year, there's hope for the SCAR.
2 SAR-21	3 CORNER SHOT LAUNCHER
DEVELOPER: Singapore Technologies Kinetics (Singapore) CALIBER: 5.56mm FEATURES: Integrated visible/ infrared laser sight and 1.5x optical scope, translucent ammo magazines. PROGRESS: The SAR-21 became standard issue for Singapore's armed forces in 1999. A better-performing assault rifle than the M-16 which the SAF replaced, it has gained a reputation as one of the world's best 'bullpup' weapons.	DEVELOPER: Corner Shot (Israel), Dynamit Nobel Defence (Germany) CALIBER: 60mm FEATURES: It has a collapsible firing-post, which is fitted with a camera and video screen, attaches to a disposable, one-shot 60 mm grenade launcher. Rounds can be fired at a 90 degree angle - other Corner Shot devices fire at up to 60 degrees. PROGRESS: Unveiled in 2004, the system does not appear to have been deployed yet.
4 FMG9 FOLDING MACHINE GUN	5 XM-25
DEVELOPER: Magpul Industries (US) CALIBER: 9mm FEATURES: Spring-loaded design transitions from box to gun with a single button-push, with a 31-round Glock 18 magazine loaded and ready to fire. PROGRESS: Non-firing semiautomatic prototype shown in March 2008. No word yet on when a firing model - much less a fully automatic one - might be available.	DEVELOPER: Alliance Techsystems (US) CALIBER: 25mm FEATURES: It has a computer-aided targeting system that allows the user to quickly aim at a target and to adjust the range of the air-bursting round. PROGRESS: The XM-25 is still in development, but in this industry-and particularly for a system that survived the OICW debacle-that amounts to very good news.

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