I've noticed lately that some manufacturers have gone to the MC (metallic coated) bullets, particulary for handgun ammunition. These have a very different look to the surface, a bit rough and uneven, not perfectly round any more. Mould marks on the tips, particularly on flat-nosed, as in .40 S&W. I have not yet been able to find out how thick that thin film of copper is... thin enough to be cut through by the rifling? down to bare lead? I''ve always preferred the FMJ bullets... far more even and precision. When the same manufacturer has both, and they are sitting on the same shelf (rare....) the price difference runs about $2 the box/50 rounds in 9 or 40. I've never yet seen FMJ in .380 anywhere in the Northwest. Only the MC. One concern is that I've a couple of new pistols to break in, and wonder if the thin sprayed copper is thin enough to be broken through by the new, sharp rifling. I really would prefer to break in these new barrels with solid clean copper...... any input, feedback, etc? after having bought the UMC MegaPacks for a long time, always with FMJ, I notice now they are sending them out marked MC. Same price as the older FMJ. Now, whenever I see a megapak of FMJ, I buy it whether I can afford it or not. Am I being too picky? Are the MC rounds just fine? My guess is, since the FMJ are more perfect in their shape, they will fly truer, thus being more accurate. Againn, any feedbackm correction, etc, on this point?