Everyone and their dog out here HATES flying colors BB's with a passion due to poor accuracy and LOTS of jamming issues.
And yet I ran 10 bags through my M249, and no less than 2 bags through my other 2 rifles with 6.03 tightbores. And although I agree they're 10% less accurate than good BB's, I've never had a jam.....
I blame poor gunsmithing
