Can a person heat there none bonded bullets and turn them into bonded? How hot would they have to be?
In theory you could, though I don't know the necessary temperature, which would vary a little depending on the lead alloy used.
But there are several difficulties, first that heating also tend to anneal (soften) the copper or copper-alloy jacket--which is why many bonded bullets have jackets that are very thick (or partitioned) toward the rear. If you bond a typical thin-jacketed soft-point, it tends to come apart, often as much as the same bullet unbonded.
Also, if the bullet isn't heated absolutely evenly, it can warp a little, which doesn't help accuracy.
