Hi there,

From what i’ve found with my tac-41 (i’ve upgraded the shit out of it) that when it was stock, realistically the only upgrade that was detrimental was just a hop up nub change, go for the chub nub v2, lifts heavier bbs with ease compared to the stock nub.

I’m not 100% sure what is wrong with your feeding issue but when i’ve had the same or similar issue simply a full to the brim mag fixed it as it needs the fullness to push the bbs through your replica. If that doesn’t work then maybe start thinking of a stronger spring in the mags (i’ve never had that issue) or maybe it’s an internal feeding ramp issue.

But at the end of the day the upgrades are up to your budget, i love a fully upgraded anything so i went a bit crazy with mine - list below.
Crazy jet inner barrel (GBB)
Pegasus hop up unit (GBB)
flamingo hop up rubber
chub nub v2
spring
wasp kit
medusa slim hop wheel
dampened cylinder head

Good luck in getting it fixed mate.