To Molly or not to Molly

[VUPDblue]

I have been moly-coating my match ammunition for years. In fact, when I first got into reloading years ago, my then-mentor suggested it. I did it "just because" and I have been doing it ever since. In my Savage rifle, I have never shot anything out of it that has not been moly coated. I use moly on the bore after every cleaning and it shoots great. What are your thoughts on using moly vs. not using moly? Waste of time or worth the time?

[Rivers]

I'm still molying my bolt rifle bullets, but just changed over to naked bullets for my AR, after shooting several thousand moly'd bullets through it. It's supposed to mitigate throat erosion, and my experience was that my groups didn't start to open up as fast with moly as without.

[Bullet94]

Good question. I think there is still a debate over this.

[texfar]

I happened accross a couple of boxes of Hornady moly 105 gr 6mm bullets for my Sako .243. After the barrel was seasoned, the groups went to the best I have ever had in the rifle. All 5+ shot groups are sub .75 MOA everytime with many sub .5 moa. Havent tried it in any other of my rifles yet, but have pondered it. Can't hurt to try I suppose.

[VUPDblue]

That is why I still do it... I have had superb results with the moly, and it is no bother to go ahead and coat a box at a time, so I keep on doing it.

[Unclenick]

I've looked at postings of moly complaints. Mostly they appear to revolve around claims of caking and corrosion under the caking. The problem is this is anecdotal, and nobody in shooting has the resources to test a statistically signifcant number of guns (like 21 or more) plus an equal size control group with these or other products. It did turn out that when moly was the growing craze, a lot of cheapie kits got on the market. Cheap moly is often recycled from metal stamping operations where it gets free iron particles in it. These, of course, can initiate rust. I've always run the NECO kit to coat bullets or purchased Sierra bullets already done by the same process. The lab grade moly just has never caused me a problem. Moly also has sulfur that is blamed for corrosion. Some kinds, like the Plate+ below are acid neutralized.

The main advantage I've observed is in service rifle matches where we have to run 80 rounds without cleaning. There is definitely less fouling when I get to the 600 yard line than with uncoated bullets. Looking through the bore scope I see a ring of moly that builds up where the chamber cut for the case neck ends and steps to the freebore. I made a tool to remove this, but it never built up to the point of tightening a neck on a round.

Another odd tidbit: If you trim and chamber a sized case and load it, then remove the bullet with an inertial puller, you will find almost no visible moly on the sides of the bullet. The case edge burrs have stripped it all off. Instead, after trimming, run the case mouth on and off a carbide expander ball in your sizing die three times. That burnishes the edge. Now a seated and pulled coated bullet has all the moly still on it. I believe this improves seating pressure consistency, and accuracy is improved by that.

If you are acustomed to put moly in the bore and want to keep using a moly product, get some Sprinco Plate+ Silver to provide a longer term lubrication. If you ever clean the bore of moly altogether, either by firelapping or with David Tubbs Final Finish kits, then consider Moly Fusion Oil, which puts a molybdenum phosphate surface finish in place that lasts 1000 rounds or so before it needs renewal. Both interesting products, but not working on at all the same principle. Each may have advantages under different circumstances. In your case the Plate+ at least will have no conflict with the exiting moly powder present.

Nick