Problem with A&K M4 RIS full auto.

[Tropic_Blunder]

Hi guys,

OK so here is my problem. I currently own an A&K M4 RIS which fires fine on semi auto, however when I fire on full auto it misfires straight away with no bb exiting the barrel.

I have tried all different makes and models of M4 mag from PMAGS to JG mags and nothing works. I'm just about to open this thing up but wondered if any of you guys had an idea of why this might be happening?

Internals are:-

SP150 spring

Deepfire piston body

Slient piston head

Madbull tightbore

Metal spring guide

2000 mah lipoly

Systema gears

Metal shims and bushing

Standard motor

I have this exact same setup in another gun and have no problem. I'm guessing its the hop up.

Thanks

Dan.