vadeerkiller

Any benefits to using moly-coated bullets and what does the moly-coating do?

ReDoT

they really help reduce copper fouling, and hence allow longer intervals between needed cleaning due to reduced accuracy. beneficial if your doing high volume shooting like prairie dog shootin

stalkingbear

What you do is trade copper fouling for moly buildup. I tried it and decided I didn't like it as you still have to clean the moly out of the bore. The BEST thing is to have a polished or hand lapped bore, which will GREATLY reduce fouling in all cases.

driftrider

Yep, and it's also my understanding that once you shoot moly coated bullets, you can't easily go back to uncoated bullets because of the moly buildup in the bore. The moly buildup is also supposedly nearly impossible to get out once deposited.

My suggestion would be to ditch any idea of using moly coated bullets. Cleaning isn't a big problem if you start out cleaning frequently, like cleaning between every group while the barrel is cooling. A frequent cleaning regimen early in the barrels life will, in my experience, lead to less fouling and copper buildup later as the barrel "breaks in". Also, you don't need to get too obsessed with getting every speck of copper from the bore. Some folks scrub for hours with Sweets 7.62 until there is no blue at all, and i've done it a couple times myself, only to find that my accuracy DECREASED afterward until I had fired a dozen or so rounds through the barrel (I'm talking about factory barrels, now, not top-shelf custom barrels that are hand-lapped to a mirror finish). Now my cleaning regimen is to run a solvent soaked patch (Birchwood Caseys Bore Scrubber usually) through the bore while the barrel is still warm. Wait 3-5 minutes, then scrub 10 strokes with a bronze bore brush, then dry patches until the patches show very little to no grey. I've found that this procedure takes out all the major crud without taking out the pore filling "base layer" of fouling that all rough factory barrels get and seem to need for consistant accuracy. If I start seeing excessive copper in the bore and accuracy is deteriorating despite the above cleaning regimen, then I'll use Barnes CR-10 to to do a deep cleaning, knowing that I'll have to recondition the bore at the range to get accuracy back afterward.

Mike

haystack

I did not know that about moly coated bullets. I have been using them in my 280 for awhile, I thought I was doing a good thing. lol Thanks for the info.

haystack

Oooops double posted

Ryan Campbell

There is another problem I've heard about with Moly coating.

Supposedly the coating makes the bullet more "slick" so that when it is sitting in the cartridge in the chamber and the primer is ignited, the bullet starts forward motion before the entire charge is lit.
All of this takes place in a nano-second but it can be enough to cause uneven amounts of pressure behind the bullet.
In other words the bullet doesnt get the full benefit of the entire charge because it has started down the barrel of the rifle before the entire charge has gone off.
I'm not 100% sure how true this is but I've heard it from some fairly knowledgeable people.

driftrider

The other drawback to moly, which is short for molybdenum disulfide MoS2, is that it's very hygroscopic, meaning that it attracts and absorbs moisture from the air, but it provides NO protection against corrosion. What this means is that in a humid or moist environment, the MoS2 will soak up water and hold it in the bore, which will cause the bore to rust unless the bore is coated with a good layer of an oil based preservative. Of course, this is fine in storage, but the oil should be removed before firing or going into the field, so that rainy day in the woods could result in a rusted/pitted barrel. Not good.

Mike

bigcountry

I would say not so much. Not uneven pressure, but less pressure. With moly, you have to rebuild your load. Maybe you use more powder charge, or even more of faster powder.

I have been down the moly road and came back very disappointed. On paper it seemed like the cats meow when it came out. I had moly kits to moly my bullets, moly the barrel, on and on. In the end, you have walked down a road you can't easily walk back iwth a gun. And gains seemed small. I will not do it again.

Ryan Campbell

bigcountry,
Thanks for clarifying that. It's been a while since I dealt with moly-ammo. It seemed to have been a fad around the late 90's early 0's but it seems to have fallen off.