Loss of about 200fps

[LazzurusMan]

Ok. I'm at my wit's end.

Stock nozzle refitted, brand new super macron bucking with omega nub, barrel polished, piston, piston head, cylinder, cylinder head all checked for compression and it's all good. 

I'm still only getting 140 FPS on .2s, and using the paper test the paper still flies out of the magwell. The only thing I can think of is the stock nozzle not sealing with the hob bucking well enough, which means taking it all apart and fitting the new nozzle. Again.

Anyone got any other theories?

 

[LazzurusMan]

So, in case anyone else has this issue at any point, I'll explain what the issue/s was.

1. Short troking and precocking without adjusting the tappet timing. Nozzle was coming forward just after the piston. Big loss of fps there.

2. Shagged bucking. Speaks for itself.

3. Crap mags. I kept getting anything from 160fps to 330 with the wind up mags I have that don't fit great but usually still feed. I switched to a poly midcap that fit better, and I went back up to a relatively consistent 343-345.

Thank you again everyone for your help, now I can focus on starting a dmr build ?

 

[Rogerborg]

Ah, I wonder if that's BBs in the feed tube pushing the nozzle up too hard.  Luke at Negative put a video up recently showing the difference between a wobbly nozzle and a firm one (fnar) and suggested very slightly flaring the end of the cylinder head tube (inside the nozzle) using a swage to minimise the slop.