TM M4A1 bb arcing down after 75FT
 

My TM M4's BBs arc down after about 75FT with hop up turned all the way up. Its a new madbull hop up and I installed it properly into the stock TM hop up and its oiled and everything. The barrel is clean and is a 6.04mm tightbore. Currently the gun pulls 375FPS.

If anyone has any idea whats wrong i'd love to hear it. I'm very confused

Maybe this applies to your situation, maybe it doesn't. I've seen a lot of used guns with replaced hopup sleeves were the little packer (looks like a ~3mm piece of copper wire insulation) wasn't put back in.

Since you installed the new hopup sleeve you probably remember if that was in or not; it usually fits inside the small port in the hop up unit where the "arm" presses down on the hopup membrane. Your new hopup sleeve may or may not have come with one (most do now).

Without it installed, you need to turn hopup almost all the way up before the tip of the arm even begins to push the hopup into the barrel, maybe your whole hopup setup virtually useless.

http://www.airsoftgi.com/images/imag...9_ghopbuck.jpg
the little thing on the right is what he is referring to

also, silicone oil prevents the hopup from working like its supposed to. the hopup adds the spin to BB, how? friction. lube kills friction, therefore kills your hopup.
So dry out your hopup unit or fire ALOT of BBs through it, I agree its easier to install a hopup sleeve if its lubed, but its not good for the function

oh ok I'm going to try and dry out my hop up first then. Yes the little nub thing is there good thing I didn't lose it, the madbull one doesn't fit so i used the stock nub.

UPDATE: Installing a dry non lubed hop up also made buy madbull doesn't produce better results.

could be that your hopup sleeve doesnt havent enough pressure on it, in which case take some insulation off a smaller gauge wire (14 gauge house wire should do it) and use that. Might be the weight of your BBs too but i doubt it, you'd have to be using .3s or higher lol

I'll try that! No i'm using 0.2g BBs. Because I'm cheap