Sjkendall

Looks like the proprietary VFC Avalon ETU.

Also make sure you have some silicone grease for the orings as well... I sell a little kit but you use anything that's suitable for orings. 
 
You want the fitment on the nozzle to be tight but not overly tight where it restricts movement.
 
Same with the oring on the piston head, needs to seal but not be too tight.
 
 

good point, just purchased a set so hopefully they do come with, will double check

Replacing the piston head O ring would be a good idea if the new one does not come with one.

O rings are built into the nozzle. You can get single or double o rings but single work just as good. You will need to measure the length of the nozzle to get the right one.

Ok so it works pretty good that's a start. How about that air nozzle. It looks like an old plastic one and some of the plastic air nozzles didn't have an o ring. Could be loosing some pressure there.
I'm guessing you have checked the hop up bucking for holes?

Yeah I think it would be good to check if that nozzle has an o ring. Plus you can check the rest of the compression side of things. V2 boxes aren't that scary.👍

The compression on VFCs out of the box is usually awful, which could be a major part of the problem.

It's not a seal in any sense bud it just helps to take up any slack between the barrell and hop.

Yes, some tighter than others. I've had both extremes - a very tight fit (eased with a bit of silicone oil), and very loose fit (rectified with a few wraps of PTFE tape). If you are needing force to seat yours in this case, after you have finished wrestling with it take care that the barrel hasn't got twisted within the hop (and therefore that the nub remains directly seated above the bucking patch).

Apply a bit of pressure , it should slip in between the front of the hop unit and barrel, helps to keep the barrel tight to the hop unit

Not necessarily the voltage; maybe a higher capacity battery with a higher discharge rating.