Ok so I had the feeding issues no matter what I tried, gun was out for game day.
was sad, still haven't used it in a game.
Upgrades: RA Tech 6.03 barrel (~363mm), stinger hop, and ra tech fire pin base and valve locker.
Here's what I all tried: NPAS nozzle, stock nozzle, stock nozzle w/ various spacers, Stock nozzle with Npas adjustable valve (surprisingly fit and sealed nicely), shaved hop-up rubber (used on that had a chunk missing due to the sharp edges around the hop-bearing hole on the brass chamber), basically, no hop-up but still sealed.
The feeding issues are the same as other ones I've read through in this thread, BB's just get fed into the hop-chamber area, but only come out in groups.
So it's:
Fire - nothing
Fire - nothing
Fire -nothing
Fire - nothing
Fire - Shotgun blast!
Repeat, number of BB's is random. Otherwise, could function as an awesome shotgun if predictable.
If my memory servers correct, this problem was less severe (though still occured) with a completely stock nozzle. (Shot way to hot, about 500). As soon as spacers were placed behind the stock nozzle/valve to try and drop it, feeding issues. (BTW, stock nozzle is now on NPAS rod. I've tried using gearbox shims between the nozzle and the smaller plastic spacer to ensure correct fitting, no help.
Problem was happening with BB bastard BB's, Armist and Green Devil Bio BB's.
After reading this thread, two things I believe I can still try, sanding down the inner diameter of part #177, and/or decreasing the diameter of the nozzle mushroom. First, I'm going to try throwing the stock barrel back in. If anyone else has any ideas of what I can try, please let me know. If I do find something that works, I'll definitely post it up so others can know one more thing to look for.
EDIT:
On the upside going through this is a good crash course on how these guns work. Which led me to this conclusion: The theoretical function of this gun is as such:
-Bolt is racked, round loaded, everything is ready to go.
-Trigger pulled, hammer fires, gas is released into the brass tube.
-Gas rushes
around the valve in the nozzle and runs into the back of the BB. There is now equal pressure around the valve, so it isn't being forced closed yet.*
-BB is pushed down and out of the barrel, as soon as the BB has exited the barrel we have a significant pressure difference, valve is slammed shut and the nozzle is sealed off.
-Gas pressure than forces the bolt back.
-At a midway point, the bolt trips something in the trigger block, and the hammer is pulled off of the valve on the magazine, releasing gas pressure.
-Momentum of the bolt, continues backwards, pulling the nozzle out far enough for another BB to be chambered
-Recoil spring eventually overcomes bolt momentum and slams it forward, resetting everything for the next shot.
Now here's my question, if this is correct, how is it even possible for the bolt to cycle if the BB stays stuck snuggly in the hop-up unit? That tells me that gas is either getting past, or out somewhere.
*Now if the "windforce" of the gas rushing past the nozzle valve were enough to close it (as opposed to the pressure difference closing it), pressure to the BB could be shut off before it's ready. Perhaps a stronger spring in the nozzle could solve this?
Edit: Second thought: If for that split second where there is a pressure difference between the BB/nozzle valve and nozzle valve/gas source as soon as you pull the trigger, and that is enough for the valve to be closed, than really, no pressure would even be getting to the BB's, so it'd just be cycling and loading them up till the gas was able to squeak by the valve before it was shut. Correct or incorrect?
Edit: BB's roll easily through upgraded barrel, so I don't think it's that.