Bulk filling Beeman QB78S questions and cheapest option?

[TucsonAZ]

Firstly, I'm wondering what the absolute cheapest bulk fill option for a QB78S is either via adaptor and bottle or just filling the factory tube.



Secondly, I'm wondering how many shots I can get bulk filling the standard tube alone given that I'm able to creat a temp differential for proper fills. 



Lastly, the cap has a screw in the end of it so I can't see a way to easily drill that and put a foster fitting in it. 



Any thoughts would be awesome and welcomed, I just picked this thing up new in the box for $60 so I'm looking forward to tinkering with it.

 

[Gipper]

Just need to replace the stock tube cap with a bulk fill air cap with foster fitting. Try Getting a hold of Flying Dragon air rifles (Mike Mellick) or you can try Archer air guns. Air Depot and Baker airgums may also carry them and they run about $40. Shots per fill will vary on tune but should equal or exceed carts and you may even pick up a few fps.

 

[Gipper]

Also these are great rifles to tinker with and many show excellent accuracy. Lots of info on tuning them up from simple to complex. I own 3 QB rifles myaelf.