1.Heat up the clamp a little bit and the bullet and then hold it on the end for a couple of seconds. If it gets red, its too hot.
2.Put some silver solder with flux core in there until it holds about 3/4 full of solder, try to stir it so there are no air bubbles.
3.Give it another shot of heat and gently place the wire inside and swirl a little bit, add heat if necessary. (watch out for the plastic.)
4. Take a deep breath of solder fumes and then blow on it.