The plastic tips were developed using the experience gathered from Remington's old Bronze Tip ammo, the purpose is to keep the slick ballistic shape, and still promote rapid expansion upon impact. Bonded cores are an attempt to keep the lead core from seperation from the cupro-nickle jacket. The Partition solved this problem by putting a partition between the tip and the bulk of the core. With the Ultra Magnums impact velocities on short range targets got so high as to cause the Partitons to rivet and otherwise fail to preform as before. In addition to that some folks didn't like the fact that the first 1/3 of the bullet tended to disappear. The Failsafe, Partition Gold, etc. are designs to keep these ultra high impact velocities from causing bullet failure. Some bullets are homogenous, which prevents the shedding of the cores. The use of these bullets in cartridges not needing the extra design features, beyond the early Partitions is a result of advertising. I like a couple of the old cup type bullets for my .260 as the velocity never exceeds their capablilties.