Heckler & Koch MP5 vs Heckler & Koch MP5K

1966–Present

1976–present

~2,000,000 estimated

Unknown

680 mm (26.8 in) stock extended, 550 mm (21.7 in) stock retracted (MP5A3); Varies significantly depending on variant.

325 mm

115 mm (4.5 in) standard, various lengths depending on variant (e.g., MP5K: 102 mm (4.0 in), MP5SD: 146 mm (5.7 in))

115 mm

2.54 kg (5.6 lb) empty (MP5A3)

2.0 kg

15, 30 rounds standard; 10, 20, and 40 round options available

30 rounds

Roller-delayed blowback, closed bolt

Roller-delayed blowback

Single-stage military trigger; SEF (Safe, Semi-automatic, Full-automatic) or Navy trigger groups available with burst-fire options

Selective fire

Rotary drum rear, hooded front post

Fixed front post and adjustable rear aperture