The pic doesn't show much, but going by that, it looks as though it was pressed in. BTW which Ultrafire is it that comes with that tailcap? Maybe if you let us know what light that is, someone who owns the same one could chime in.
turn it so we can look down at the spring, most lights I have owned require a pair of needle-nose pliers to disassemble the tail cap. Are there two small holes opposite each other on the ring?
no holes ,, just a black piece(looks like a washer) and the spring is just pressed inside the plasitic ring ,, i can pull the spring out basically i think it is press fitted but i wanted to make sure before i pryed it up (in case it is glued in and or if i pry it out will it go back in securely? ,, it is the light in this post http://www.candlepowerforums.com/vb/showthread.php?t=220063
Does it look thread inside the tail cap?
it would not hurt to put two small holes in the plastic ring.But looking at the picture it seems you could just grip the plastic ring with pliers and try to unscrew.
no holes,just a flat plain hard plastic washer looks like to me and i tried to grip it with pliers and turn it but it would not budge to turn and starting to put a knurl mark in the plastic so i stopped so i wouldnt mess it up