SAR-21

While the United States has repeatedly—and spectacularly—failed to replace the aging M-16, Singapore has been using a newer and possibly better-performing assault rifle since 1999. The SAR 21 replaced Singapore's licensed version of the M-16, and has gained a reputation among gun experts as one of the best “bullpup” assault rifles—where the action and magazine are behind the trigger—on the market. It has a smaller overall profile than the M-16, without sacrificing barrel length (the shorter the barrel, the less accuracy at longer ranges) and significantly more manageable recoil, due in part to the weapon's center of balance. The recoil tends to drive directly back against the firer, instead of pushing the barrel upwards.

All of this is useful in an assault rifle, but particularly for urban warfare, where more compact weapons are crucial to maneuvering indoors, and where close-range, fully-automatic fire is more common. The SAR 21 has a Kevlar cheek plate to deal with chamber explosions occurring next to the user's face, a regular safety issue for bullup weapons. It's also one of the few assault rifles in the world equipped with an integrated laser aiming device.