Hop, Power and parts ramblings

[Skara]

Alright.

 

It's been two weeks now, I rebuilt the 7" M4 because I wanted to squeeze a little more RPS and a little more snappiness on semi.

I went from 13:1 -1t and a m105 spring to 12:1-4 and a m110 spring, still on a warhead 36k powered by a 7.4v 1800mAh 65c.

 

Gained 4 rounds per second (25 now) and a silly stupid shot to shot consistency in semi auto (less than ±0.5 m/s) but as soon as I try to set the hop, I get a weird but very consistent power loss of about 3/4 m/s.

Compression set is exactly the same bar the cylinder size (went for a more aggressive porting that slightly bumped up the power while remaining overvolumed to push 0.32s) and gearbox timing, which was a bit off in the previous iteration and now it's great given that out of 15 shots the lowest was 100 m/s and the highest 100.6 on 0.2s, similar results but obviously lower for 0.32s.

 

The thing is driving me nuts because this gun used to do the opposite, it gained a little more power by adjusting the hop.

 

Tried with the previous cylinder but overall power dropped a little, both on 0.2s and 0.32s.

 

Tried a couple of different tappet plates, tried a couple of different hop rubbers (both style and hardness), tried lightening the piston assembly by removing the bearing but it made things worse so now the bearing is back in place, also added a washer to the piston to give it more weight but unfortunately couldn't fix the issue.

 

Also noticed that the sound changes dramatically when adding hop, the gun does NOT pme, piston moves freely, after 1000 shots there is no damage to the piston or the sector. Air seal is spot on.

 

I just want my extra power back

Pls help.

 

Edited November 3 by Skara