 The R5, when compared to the larger R4, has a barrel that is shorter, together with a shorter gas system and handguard.It also lacks a bipod, and the flash hider does not support rifle grenades.In the 1990s, an even more compact personal defence weapon variant of the R5 was developed for armored vehicle crews, designated the R6, which has a further reduced barrel and a shortened gas cylinder and piston assembly.