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Posted: 1/8/2006 6:17:49 PM EDT
I heard a lot of good things about these bullets, know how about the bad. Is it true they keep your barrel cleaner or it makes it easier to clean. take it easy on me nowhinking.gif
Link Posted: 1/8/2006 6:40:03 PM EDT
It depends who you ask. Different shooting disciplines will get you different answers. I don't have any quantifiable evidence to back up my opinion.

Moly is never completely cleaned out of a barrel. It's not like carbon or copper. Even JB paste doesn't remove all of it. It may reduce copper fouling, but then you have moly fouling. I'm a guy that likes my barrels clean, yes, after each firing session. I have spent hours trying to get moly out, to no avail.

The small velocity gain is not worth the extra work for me. I shoot nekkid bullets.
Link Posted: 1/8/2006 9:29:03 PM EDT
I just read someplace (lots of help huh? Sorry 'bout the lack of a source.) that it absorbs moisture from the air? Anyone know of any truth to that?
Link Posted: 1/9/2006 4:40:46 AM EDT
Yes pure moly absorbs water. It decreases pressure and thus velocity and requires a greater charge to return to the original pressure and only then will you gain velocity.
Link Posted: 1/9/2006 4:50:25 AM EDT
[Last Edit: 1/9/2006 4:50:55 AM EDT by twonami]
here is what the oracle says:

Q. What is Moly? What is it good for?

The term “Moly” refers to Molybdenum Disulphide. This is an extremely fine powder which acts as an inert lubricant between the bullet and the bore. It is coated onto bullets to reduce the friction incurred on the bullet as it passes down the bore. The reduced friction is said to prolong barrel life, increase velocity and the ballistic coefficient, and increase accuracy. The moly coating does not build up in the barrel, as each successive shot removes any excess material from the previous round.

If you are worried about barrel break-in on new rifles, do not use moly to begin with. The extra friction from an uncoated bullet is necessary for proper break-in.





Q. Moly sounds hella-cool. I'm going to use it with all my rounds from now on!

Slow down there chief, Moly isn't sliced bread or anything.

The biggest downside is that Moly is hygroscopic – meaning it is capable of absorbing water from the air. This water is then trapped between the moly coating and the barrel, which is definitely not a good thing. A quick fix to this problem is to run an oiled patch through the barrel after each shooting session. The oil will block moisture from being absorbed.

Moly is also extremely messy, and it likes to stick to everything. It is also easily rubbed off of bullets, leaving a slippery film on whatever it touches. With practice and experience, however, this can be minimized.

The biggest threat to barrel life is not addressed by the use of moly coated bullets: Throat erosion. Throat erosion is not caused by the friction of the bullet, rather the high pressure and high temperature gases that are present in every shot. It is not very often that a rifle barrel wears out it’s rifling before it suffers from extensive throat erosion.

good reading

Link Posted: 1/9/2006 10:13:11 AM EDT
So if your barrel is broke in and you start using moly coated bullets, you have to make sure to run an oiled patch through your barrel after some shooting, like before you put your gun away for a while. But once you begin using moly and your barrel becomes properly "seasoned" with the moly residue, is it true that switching back and using copper will affect your accuracy? I guess what i am asking is can you use both? I just got 100 rounds of Hornady 55 gr. V max bullets and want to start reloading them but i don't if i am going to stick with them. Does this make any sense to anybody?
Link Posted: 1/9/2006 11:07:44 AM EDT
There is no such thing as moly fouling, that is a misnomer. Moly will build up to a certain point and that's it. It won't layer on itself over and over.

Moly allows shooting accurately for longer strings due to reduced carbon and copper fouling. It's use in HP circles is mixed, but there's one guy over on NationalMatch.us that ran an entire season using nothing but moly bullets. His cleaning regimen consisted of pushing a dry patch down the bore after each session. No solvents, no pastes, nothing else. His barrel shot the same at the end of the season as it did brand new, under 1 MOA. He was questioning whether he should clean with solvents and start over next year or just put it away and pick up where he left off. IIRC he never applied any oil or corrosion inhibitor during teh season and he never mentioned any corrosion in his bore.

Benchresters who've used it clean w/Kroil and either JB or Shooters Choice. The goal is just to keep carbon and copper in check -- you never want to remove moly, you want to keep it there.

DevL is right -- it reduces pressure and velocity, so to get back to your naked bullet's velocity, you have to add powder. Supposedely when you get to that point, you'll have equal velocity, but reduced pressure. You could keep going up until you matched pressure at which point you have a bit more velocity.

If you start with moly, make sure your bore is cleaned down to bare metal -- no fouling of any kind. If you can, pre-treat the bore with some moly before launching coated bullets down the bore. That will help season it more quickly. You could shoot naked bullets later, but your moly coating will wear off and copper fouling will resume in time. Personally I think it makes more sense that if you like the moly, to stick with it and not alternate bullets. It makes it easier if you handload of course.

I don't know which barrel material offers better corrosion resistance, 416R SS or chrome-lined CM. But if BRs can get by without any corrosion problems, I think the warning that moly can cause corrosion is overblown. I'm sure a simple patch with CLP or some other corrsion inhibitor would be entirely satisfactory in keeping corrosion at bay.

Link Posted: 1/9/2006 12:57:47 PM EDT
I use them,,, with no regrets
Link Posted: 1/9/2006 3:22:02 PM EDT
Moly coated bullets does reduce friction and you will loose velocity with the same powder charge. The reason why you loose velocity is because the power curve has moved down the barrel because the bullet has less resistence, there by exposing more sq inches to the powder lessening the pressure.

Adding more of the same powder is not the answer, it only moves the power curve further down the barrel until you develop a flame thrower. If you are using a semi you will be increasing pressures at your port, inturn increasing recoil. The best way is a slightly faster burning powder, trying to keep the power curve at the same location, in fact you may end up using less powder.

The draw back is no individual out there has the equipment to measure and graph the power curve, only ammunition and powder manufactures. If you are going to try to changee powders (which I suggest with Moly coated bullets), talk to a powder manufacture they will guide you, start low on the charge weight and increase it slowly watching for pressure signs.


Art - Silver State Armory
Link Posted: 1/10/2006 5:14:15 AM EDT

Originally Posted By johnssa:
Moly coated bullets does reduce friction and you will loose velocity with the same powder charge. The reason why you loose velocity is because the power curve has moved down the barrel because the bullet has less resistence, there by exposing more sq inches to the powder lessening the pressure.

Adding more of the same powder is not the answer, it only moves the power curve further down the barrel until you develop a flame thrower. If you are using a semi you will be increasing pressures at your port, inturn increasing recoil. The best way is a slightly faster burning powder, trying to keep the power curve at the same location, in fact you may end up using less powder.

Art - Silver State Armory



For .223-sized cases, is this really a problem? Isn't the adjustment up in charge maybe .5 grain to reach the earlier pressure? I could see running out of case capacity as a reason to drop back to a quicker powder, but my experience with larger cases was the same powders that worked before, just add a bit more if using moly.

I do run higher neck tension though with moly bullets for the reasons you mention. That extra bit of grip gets a cleaner burn.
Link Posted: 1/10/2006 1:07:17 PM EDT
If you are only looking at reducing wear in your barrel and not really trying to get more FPS, yes adding a little more powder would be OK. But if you really want to get the most out of a moly coated bullet (i.e. FPS) then change the powder.
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