In factory ammunition, the plating is generally as thick or thicker than standard jackets. You probably won't notice a difference, unless you're shooting rocks and steel plates. And... if you are shooting rocks and steel plates, you'll probably like the fragmentation/splattering better than that of FMJs, anyway.
There are actually many plated bullets on the market, that most people don't even know about. For example, just from Speer: Gold Dots, DeepCurls, TMJs, and UniCors are all plated bullets that most people assume are jacketed.
Component bullets (for reloading), on the other hand, generally have less plating. That is, of course, since they're more of an 'economy' bullet. Most component plated bullets end up being pushed at moderate velocities that are faster than lead bullets, but slower than jacketed bullets. It has more to do with the maximum yield pressure of the bullet, than the barrel design or firearm type.
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