It's pretty rare, since getting both systems to work reliably is difficult, and introduces some additional mechanical complexity - the FN Minimi (adopted by the US as the M249) has such a system, but it's apparently not very reliable when feeding from magazines. The Soviets had a prototype with a dual-feed system, but never adopted it.
It's pretty rare, since getting both systems to work reliably is difficult, and introduces some additional mechanical complexity - the FN Minimi (adopted by the US as the M249) has such a system, but it's apparently not very reliable when feeding from magazines. The Soviets had a prototype with a dual-feed system, but never adopted it.