I just called Lost River Ballistics to order a box of J36's .308-180gr for my 300 Win Mag and they tell me they do not recommend moly coating the bullets.
Any reason for this, as I've always been under the impression moly was a good thing, that it certainly would not do any harm. With Moly coated rounds my velocity sweet spot is at 79.0 grains H4831SC @ 3147 ft/s.
I'm glad someone finally asked this question, if you look at the construction of the bullet I think that might effect it when it hits, but I could be wrong though. When you asked, did they say the same thing for the J40?
[ 04-08-2003: Message edited by: Nighthawk ]
a whisper from this little friend of mine goes a lot way.
Did they say why they don't recommend moly? I doubt it has anything to do with their bullets in particular and is likely just where they stand in the for or against arguement on moly. Moly should have no affect on what the bullet does when it impacts an animal.
I am on the fence over the issue and have no evidence to suggest it lowers psi in all my testing with it. We've shot moly coated Sierras vs non-coated and there is no difference in MV or PSI at all, so...
I recently read an article about the new Barnes "Triple-Shock" groove bullets in May/June Rifle Shooter by Clair Rees, it was the most over blown article I think I've read to date. Sometimes I think these guys have stock in the company! No doubt the new bullet will be nice, and I like Barnes, but make me puke with all the claims and subjective and so infered "facts" are completely ridiculous!! [img]images/icons/rolleyes.gif[/img] I swear some of these guys are better fiction wrighters than fact reporters!
A claim that the bullet retains all it's velocity at lower psi as is their claim with the XLC bullets is for the most part BS in all my tests, when a cartridge looses pressure with a given load because of a coating or whatever it almost always looses the velocity at the same time, so you need to use more powder to gain back the psi and thus velocity, in some cases you may gain a little extra velocity but very few in my experience.
Well I called in again, this time I talked to Warren.
-Warren, I hope I'm quoting you correctly-
He states that the moly position is not because it is detrimental, rather that he has not seen any net benefit over his years of working in the industry. That load workup can be more difficult due to more factors to consider in the process. He went on to state that the claimed 'increase in velocity and cleaner barrels' - the two great claims of moly proponents - is not there in the majority of guns that have passed through his shop. The moly apparently builds up and must be cleaned out every 25-30 rounds or so. He has seen guns coming in that have moly over copper over moly over copper, etc. that must be worked away to get back to a clean barrel.
I've been on the fence on this issue as well. Apparently the benchrest community have all moved away from moly. The local Graf's reloading shop here in St.Louis (where I'm at this week) used to sell moly kits and couldn't keep them in stock, now they rarely move one - some sort of fad they claim.
Moly never make velocity highter , for a same load of powder( same other components ) velocity is lower , because pressure chamber is lower with moly.
moly make engraving of the bullet more easy with less force because you have a lubricant on the bullet , nothing more nothing less , VAUGHT in is very good book say that moly make pressure lowerby chemical reaction between moly and powder but I have any other informations on this fact .
I use moly on all my bullets and clean my barrel often , that just improve pressure level with long bearing surface bullets
perhaps the only facts for J36 LRB is that the balistic point of the J36 can be hurt durring tubling process.
J40 with very long bearing surface and hard alloy can perhaps be improved by moly , in any case copper fouling is a nightmare with LRB so you need to choice between two nightmares
heavy copper fouling or mix of moly and copper
Moly has a high thermal absorbancy ratio; it takes a lot of heat to make it change it's molecular state. Typically, this lowers combustion temperature, and therefore chamber pressure and velocity to a slight amount--this loss is consistant <to a degree> for the weapons I've tested, and is usually in the ball park of 30-45 fps behind an equivelant load minus the moly. As for friction reduction, well hells-bells, the frictional coefficient in a barrel is in the neighborhood of 2% or less, so no, it isn't going to reduce friction--not nearly durable enough. Why use the stuff? Well, IF you can plate the interior of the barrel with it, it seems to shed copper, or repel it, somewhat. Will it hurt? No. Will you clean less often? Maybe a little, but I wouldn't recommend getting lax, or you'll end up in the barge of people that tote, "This crap's gummed ma` bore!--just look at this?!" I believe there are some new methods coming about that will be more successful, but just like the women in Vegas, you can expect the exchange rate to be proportional. [img]images/icons/wink.gif[/img] Temperature reduction while maintaining a case full of powder is the MAIN advantage I see.
do you mean the coating it leaves on the throat might help reduce throat errosion somewhat because of it's high heat resistance? If so, good point, and something worth considering too. I know alot of BR guys still use moly and claim cleaning often is far less necessary, some don't clean for a 100 round or more before accuracy fades!!!
Before this they said 10-30 rounds was the most they could get and stay competetive.