feeding problem?

[Vandal*Qc*]

ok, I have an ares mcm700x. I juste changed the rubber bucking and after that, I had feeding issues. no bb coming out, weird spring sound and bb just falling of the barrel etc. the hop up was still set to zero. so it wasnt to much hop.
Since the only mod made was the bucking, I've put back the original one and I have double check everything while putting it back together, but it still do the same thing. but once in while, it shoot normal. every time its does it, the handle have a little restriction while putting it back down. So im thinking of the feeding mechanism but I really dont see whats wrong with it.
any suggestion?

[Hectic]

I'm not sure what the sound may be however I have had alot of times where putting a new hop rubber causes jams. Mostly in VFC hop units but some LCT as well as aftermarket ones. Try putting a bb into the hop up and barrel assembly and see how much force is needed to push the bb past the hop rubber. Could be as simple as selecting a different brand or hardness of rubber.

[Vandal*Qc*]

the cylinder unit seems to work real fine. I think the weird noise when it doesnt fire is because the piston isnt able to move all the way because the bb is blocking the airflow.
but since I have put back the original bucking and it still does it. I suspect something with the 'feeding tube'. I dont really know the real name but since its an ares sniper rifle with the mag at the right place, there's a plastic tube that contain some bbs between the mag and the hopup. I suspect something there to be misalign or something. but I really dont see how. anyway, Im gonna disassemble it again and try to take a couple a pics. it might help you help me. or even better, resolve the problem.
thanks

[Hectic]

I almost certain the issue is the assembly is tight. This causes the hop rubber to either stretch and be too tight to apply hop properly or bind up around the feed end (you can almost see it as a wavey ness in the opening in the rubber)
When it's tight like that it'll take real force to feed the bb past it. Once it's in it'll fire but you can damage a nozzle (or other bits in an aeg) as it can't force the bb past the opening in the rubber easily enough.

[Vandal*Qc*]

I've took pictures. And found the problem at the same time.
Hectic is really close.
while thightening the hop up, the bucking slip by like 1mm and was blocking a little little the hole where the bbs come from. and since there is not much force apply to them at this place, they were not able to go through.

20160415_225255.jpg

20160415_225350.jpg

see the small red portion blocking the hole? thats the problem. So, I hope this can eventually help somebody else. and thanks for the help.