Green Gas Blowback that wont blow back. Please Help.

I have a Colt 45 green gas blowback pistol that wont blow back! i have oiled the slide and given it enough green gas in the clip, and still the gun wont work. This problem has been going on for about 2 months now. The pistol is not low grade, it is full metal and 400fps. If you might have any ideas about what the problem is, please just tell me. I need you guy's help!
here is a vid showing what my problem is-

https://www.youtube.com/watch?v=Ab6siriimOM

PLEASE HELP ME!!!!!

ur sure there's nothing in the slide? or something that's caught on something else in the slide?

Maybe its just jammed or the blow back action is blocked somehow . To the best that I can understand the gas propells the bbs while pulling back the slide also . Will the airsoft gun fire if this is the case then the gas probaly just isn't getting to the slide . If the airsoft gun wont fire I am not too sure . Perhaps you can take it back and let a perfession look at it . That would be the smarter thing to do if it is still under warrenty and if not send it back anyway they may charge to fix it or to charge you to replace it entirely but either way youll have a fixed or entirely new airsoft gun .

Can you take a picture of the slide disassembled from the frame? I have never seen something like this happen but from my knowledge on GBB's I am going to say that either the mag isn't releasing enough gas or the nozzel is damaged....

sticks

well i don't know how to take the slide off.

You take the slide off by a series of button and lever pushing depending on which airsoft gun you have . I am not sure about this airsoft pistol but there should be a lever right under the slide . Press it and pull on the top of the slide and it should come right off . But please don't try this on your airsoft pistol until you have checked first I mean it works on my M9s but it may not on your Colt .45 .

ok