so what you do is take the recon barrel and unscrew it so it can open up. once opened it should look something like this. ( sorry that theres some parts missing i post everything i made after i moded it.)
now take the tube in the center of the barrel out like so.
now put the barrel back togather and screw everything back in but forget the sight and two orange half circles, those are unneeded.
now just take the barrel and some tape and tape around any end of the barrel you like if you can see how i did mine try and do something like that.
now stick the taped end into the front of the barrel which is the side where the sight use to be. make sure the barrel sticks in there nice and tight so that the barrel doesn't slip out easily. if your having trouble with that then keep on taping around the end where there is tape and repeat this until the barrel stays in the outer part of the barrel nice and tight.
once youve done that your barrel should look like this. if it does it means youve done everything right.