M249 with a box mag on 7.4 lipo (driving both). Shoots kind of like a shotgun and some fps variance. Runs slightly less like a shotgun on midcap m4 mags.
Put an 11.1 in at lunchtime "for a laugh" and to see if the gearbox would explode. BB's now nailing it out in a straight line (or considerably straighter, from both sources.
This doesn't make much sense. I can only assume that somehow the box mag is delivering differently and the load process is what affects the accuracy normally. Definitely weird though.
I only ever planned to run it on 7.4 so now this is an issue. Especially as it's got 13:1's in it. So then I'd have to think about shaving teeth for PME and so on.