Moly coating - Load Pressure

338winmag

Handloader
Jan 9, 2011
369
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Just inherited a reload job for a 30-06 where the former reloader moly coated the rounds. Does this in effect moly the barrel and if so, will new "non-moly" reloads show less pressure than if the barrel had never shot moly loads?

Thanks
338winmag
 
Molybdenum coated bullets will reduce the pressure in the bore by about 3% since they're more slippery than non-coated bullets. Due to the lower friction, there is less pressure which means there is reduced velocity by about 1-2%.

What does this mean to the bore? Since it is a lubricant, it leaves a small amount of material in the barrel. If you clean the barrel after shooting moly-coated bullets, there will be some grey-ish stuff on the patch--the moly--but you're likely not to get it all in one cleaning. I really question why you would want to get it all except you don't want too much of it to the point it effects accuracy.

The small decrease in velocity is not going to be noticed unless you're seeking a lot of chronograph readings at the highest possible levels. I've never seen any proof using a scientific approach that moly bullets increase barrel wear. Most maufacturers don't sell moly bullets, I'm assuming it is because there hasn't been a consumer demand / need for the item.
 
My understanding about moly is that other than being a pain to work with, if you were to mix molys with non-molys the non-molys would basically shoot out the moly coating in the barrel. Someone please correct me if I'm wrong. Jimmy
 
I used Moly coated Barnes bullets for awhile (blue). They were not very accurate anyway and I went back to Noslers with no adverse effects. I also use Lubalox (CT Silvertips) with good performance and accuracy. The coating does not stay in the barrel and have any effect for more than a few shots of regular uncoated bullets.
 
THere was an article by Rick Jamison on moly in barrels. Apparrently he was doing do experiments with a 22-250 where he coated the barrel with moly, than shot moly coated bullets. He did say good things about the process until it came time to remove the moly completely after the experimentation. He was horrified to find the barrel had rusted/corroded under the moly coating. IIRC, the article was in Rifle magazine. Still it might have been Handloader too. I just don't remember. Jusst something to think about.
Paul B.
 
338winmag":ad58z1yf said:
Just inherited a reload job for a 30-06 where the former reloader moly coated the rounds. Does this in effect moly the barrel and if so, will new "non-moly" reloads show less pressure than if the barrel had never shot moly loads?

Thanks
338winmag

I have hear you can tumble the moly off of the bullets but have never done so myself, never had a need. If anyone knows for sure please chime in.


Bill
 
You use it enough in your rifle and it will build up in the throat area affecting after a while your accuracy because it builds up due to the fact you can't clean it with the regular stuff we use to clean carbon and copper out of our barrel. Then when it builds up enough it will finally tear loose and actually can take part of the throat with it. Guys think it is keeping copper out of their barrels because when they clean their barrel there is not any copper sign or hardly any at all on their patches.

Well, what they don't realize is they are not cleaning out the Moly, so in essence you have every time you fire a round through your rifle you leave a moly, copper, and carbon layer and this happens every time you shoot a round. When accuracy goes and you clean your rifle, wondering what is wrong, because you don't have much copper coming out of the barrel? it is because you have these three layers of moly, copper, and carbon with every round you fire that is coated with the Moly.

The moly is not letting your cleaners get to the copper and carbon build up. Moly can become a big mistake after a while of using it. If moly were such a wonderful thing, why doesn't every manufacture of fire arms coat their barrels with it and then recommend every one who buys their rifles use moly, but no manufacture recommends this, why not? If moly is such a wonderful thing why don't any of the bullet manufactures use it on all of their bullets they manufacture and ship out for sale or suggest that their none coated bullets be coated with moly, yet no manufacture recommends this? No way will I use moly in any of my rifles period.
 
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