Odd tightbore experience

Ok so...
Barrel is clean, and hop up fits. Ill measure the length tommorow, and im new to opening up guns so I have no idea what the bucking does or what could be wrong with it.

Yeah just over 350 and the guy at the local shop installed it for me. I'm sitting in with him whenever he does work to guns to find out how to do it. What do you mean put it back together? I cleaned the barrel before he installed it. Here's exactly what happened when he changed it:
-Took upper off lower receiver
-Slid out inner barrel and hop up assembly
-Took inner barrel out of hop up assembly
-Had trouble getting thin rubber sleeve out of hop up assembly
-Got it out, sprayed silicone oil on it, slid it onto tightbore
-Reassembled it

Could he have damaged the thin rubber sleeve when he was getting it out?

Ah thank you. Yes he sprayed silicone oil inside and out and made sure the whole thing was coated. I'll redo it tomorrow. Thanks again!

Shooting at right around 550 with a .2 but I have no idea with the .36s that I use. It's hitting the target (bare part of tree) 7-8 times out of 10 times. I used a meter wheel clicker thing that rolls on the ground and clicks every meter to measure. When I got to the hedge I stood up a ladder so I'd know where to start from, walked around the hedge and continued. Now it is about 108 meters to the base of the tree, but since the target is part way up doesn't it shorten the distance a bit? As for internals it has a new hop up rubber, tightbore, deans connectors, new spring, motor, and piston. I take no credit what so ever for installing them, because I'm just not comfortable with possibly throwing away $800 and the parts.

The target is probably about 4 feet tall and at least 2 wide but could be more. The tech is the owner of the store. My bipod is a saw horse since I'm aiming upwards. I'll try to take a video tomorrow or Friday if my phone comes in.