I found a box of moly-coated .30-150gr JSPs once at a gun show and shot them in my 03. The rifle digested them without complaint or comment, and they were as accurate as other 150-gr bullets. Moly coating was developed by Merrill Martin of Precision Shooting back in the 80s, IIRC. The claim was that the same loadings achieved higher velocities with lower pressures and the same accuracy because the coating was so slick. The “proper” coating method devised by Martin involved tumbling the bullets with lead shot and a tablespoon of molybdenum disulfide. This would allegedly peen or “hammer” the MoS2 into the surface of the copper jacket, where it couldn’t be wiped off in casual handling. Anyone who has used MoS2 lubricants can imagine what a filthy process this must have been. I imagine everything, including the operator, got well-coated with the lubricant. It didn’t help that the inevitable innovators came out of the woodwork with variations on the process (same as with Martin’s other development, “fire lapping”), to announce that 1) Yup, it worked great; 2) It didn’t work worth squat; and 3) Whether it worked or not, the “Moly” got pressed into my bore, it couldn’t be cleaned out, and the nitrogen oxides of the powder combustion oxidized it to sulfuric acid which ate the rifling. Martin was a careful experimenter who showed all his data and procedures, but it seems the advantages didn’t justify the effort for most people. Sort of like Elmer Keith’s experiments in “forward ignition” of powder charges. The new coatings are baked on enamel, providing an analogue to a plated “jacket” on a cast bullet. High velocities (for cast bullets) are possible, but nobody has figured out how to make the coating thickness as even as a bullet jacket, so it’s OK for pistols but not optimal in rifles, where it would really help. Much like other schemes to “shoot cast bullets HOT!,” only a few report success, and the threads containing such reports On Line are rife with contumely. The chosen few seemed to do well with such innovations, but I recall there was a master spoiler who worked for Sierra, testing their bullets out of four different barrels to find the accuracy typical for the average customer. He sometimes tested the new developments if he had time available, and most of the touted advantages vanished when his results were published. IIRC, he tested the moly bullets, and neither the advantages nor the disadvantages were evident.
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