I wouldn't be surprised if it caused feeding issues. It's a rimmed cartridge.
Bren LMG's seemed to have no glaring issues with handling a rimmed round. Yes it's a more difficult design to engineer, true.
But it's like the fellow a page or two back that commented on 10 rds being not that effective... it pretty much made you big dog on the battlefield in WW2.
Heck the FSU designed the Dragunov to use a 10 rd magazine utilizing a rimmed rd...some folks here would give a kidney to have one of them.
Different time and a different place. 10 rds and a rimmed cartridge now, madness.
Then... please!