Re: Don't understand treating copper plated like lead bullets
The precaution applies to rifle as well as pistol bullets. Yes most handgun loads are under 1200 fps but if you go much over that the barrel rifling will simply cut the plating and the lead core will go downrange amid a bunch of copper shreds. The target will look like swiss cheese. Keep in mind the plating is only a two or three thousandths of an inch thick, whereas a jacketed bullet may be twenty thousandths of an inch. I don't know the exact thickness but jacketed is MUCH thicker than plated.
As long as you keep the velocity down you should have no problems. I load 9mm to about 1100 fps and I've never seen a shredded bullet (yet).
However if you intend to load for rifle for target or plinking, then you need to be very careful of the velocity. Don't load to 2700 fps and expect to do much with the bullet.