[lurkingknight]

I replaced the hop rubber, same effect. tried softer rubber, no change. Tried different brand of rubber, also no change. Reverted to a stock barrel with stock rubber using the m-nub, also no change. Replaced the nozzle and cylinder heads with brand new versions of what was working before, no change. The gun just stopped feed/shooting correctly at some point and refuses to shoot full mags.

If the angle of the nozzle worked when new, but was worn to the point where it would impede feeding, a new one should have fixed it (logically) Same with any chance the cylinder head and nozzle relationship also wore to the point of changing the feeding characteristic.

The only other possibility is tappet plate return is being interfered with with a full mag. I observed a similar behavior on my g36 when the tappet hit the trigger shuttle return spring on it's way to battery, there was evidence of this when I opened up the gearbox and discovered the shuttle spring was mangled.

The problem here is that the v6 spring is a compression spring, and the tappet itself is isolated completely so it can't hit anything during the cycle, so my only working theory is that the tappet spring is weakened such that the force of a full mag is causing enough drag to slow the tappet down during the return to battery position. Because there's no definitive replacement spring for a v6 tappet spring, and I don't have a method of measuring the spring rate, I can't be sure I can find a proper replacement, though I have found some with similar dimensions but varied rates from 4 pounds per inch to 16 pounds per inch.