Moly-Coating
02-23-2010, 07:37 AM
#2
Nontypical Buck
Join Date: Jan 2008
Location:
Posts: 1,408
This was all the rage awhile back. Moly is a very slick material. My understanding of the theory is that it was supposed to reduce friction between bullet and barrel, increasing velocity at a given pressure while reducing barrel wear.
It seems truth has not lived up to theory. While moly still had believers, I've known people who swore it off due to ruined barrels (the "moly ring") and had this confirmed by a well-known gunsmith.
Moly is used in the hand-lapping process of custom barrels to help fill in and smooth the bore. Personally I think moly is good for making barrels but bad to put on bullets.
It seems truth has not lived up to theory. While moly still had believers, I've known people who swore it off due to ruined barrels (the "moly ring") and had this confirmed by a well-known gunsmith.
Moly is used in the hand-lapping process of custom barrels to help fill in and smooth the bore. Personally I think moly is good for making barrels but bad to put on bullets.
02-23-2010, 10:23 AM
#3
Guest
Posts: n/a
Molybdenum disulfide is a dry film that has the property of embedding itself into metals and staying there.
I went down this road. In the end, not worth it to me. It works. A properly moly'd barrel shot with a moly'd bullet, you can gain 100-150fps. But, you have to venture out on your own with load data. Go past max and understand the signs of trouble. Carefully chrono'ing your load. It cuts down copper fouling. And an added benefit of repeatable cold bore performance. I can vouch for this.
Sounds groovy don't it?
Here is the bad news. Its hydroscopic. Sucks up moisture. And if you remove it every range session, then it takes several shots or "moly treating" of the barrel to get back to where you was before. So most guys leave it in the bore. Don't clean but every 100's of rounds to get the benefit. Also, you get buildup every few hundreds of rounds and get a moly ring, which causes huge pressure/velocity spreads. Sporatic performance. Its messy, and you need a separate tumbler.
I just got to the point, where I just wanted to buy bullets and shoot. I didn't like having these heavily fouled bores, and worrying if it was pitting my barrels.
Another tip, make sure you get the stuff made for guns. Some out there, used in the machinery world for large bearings, can and will pit your barrel.
I went down this road. In the end, not worth it to me. It works. A properly moly'd barrel shot with a moly'd bullet, you can gain 100-150fps. But, you have to venture out on your own with load data. Go past max and understand the signs of trouble. Carefully chrono'ing your load. It cuts down copper fouling. And an added benefit of repeatable cold bore performance. I can vouch for this.
Sounds groovy don't it?
Here is the bad news. Its hydroscopic. Sucks up moisture. And if you remove it every range session, then it takes several shots or "moly treating" of the barrel to get back to where you was before. So most guys leave it in the bore. Don't clean but every 100's of rounds to get the benefit. Also, you get buildup every few hundreds of rounds and get a moly ring, which causes huge pressure/velocity spreads. Sporatic performance. Its messy, and you need a separate tumbler.
I just got to the point, where I just wanted to buy bullets and shoot. I didn't like having these heavily fouled bores, and worrying if it was pitting my barrels.
Another tip, make sure you get the stuff made for guns. Some out there, used in the machinery world for large bearings, can and will pit your barrel.
02-23-2010, 02:56 PM
#6
Guest
Posts: n/a
Moly has been around for a long time. It will lube about anything under temp. The only advantage over your oil lubes is it handles high temps without going away.
I would suggest some dry graphite or lithium for your derby car
I would suggest some dry graphite or lithium for your derby car
02-23-2010, 04:25 PM
#7
Spike
Join Date: Oct 2007
Location: S. Central NC
Posts: 21
On a microscopic level moly (Molybdenum disulfide) is made up of round or oval platelets. The platelets have a magnetic-like attraction to metal. As the platelets attach to the the metal the attraction weakens so they will only build-up to a certain thickness (a few microns), the rest of the platelets slide off.
When you coat a bullet with moly and fire it through a barrel some of the moly on the bullet attaches to the bore of the rifle. After a few rounds the bore is coated with moly as well as the bullets so the contact between the bore and the bullet is reduced which means less friction.
How less friction? As Tubbs (I believe) explained it.
You take a board, prop one end up on a table with the other end on the floor (a ramp), you put some magazines in a cardboard box (for weight), put the box on the high end of the board and give it a little push. The friction between the board and the box doesn't allow the box to slide very well. But, if you take a few decks of cards and spread them out the length of the board then put the box on the board it will side down the board very easily. The cards kind of act like the moly platelets.
That's the best explanation I've heard for the lubricity of moly.
It does work. Take your pet load and load a few rounds with non-moly coated bullets and load a few with moly bullets and fire them through a graph. Fire the non-molys and watch the velocities, then fire the molys. With each moly shot the velocity will drop until the bore is coated and the velocities stabilize. Less friction, less pressure, lower velocity.
As far as the moly debate goes...I'll just pass along this information and leave it at that.
When you coat a bullet with moly and fire it through a barrel some of the moly on the bullet attaches to the bore of the rifle. After a few rounds the bore is coated with moly as well as the bullets so the contact between the bore and the bullet is reduced which means less friction.
How less friction? As Tubbs (I believe) explained it.
You take a board, prop one end up on a table with the other end on the floor (a ramp), you put some magazines in a cardboard box (for weight), put the box on the high end of the board and give it a little push. The friction between the board and the box doesn't allow the box to slide very well. But, if you take a few decks of cards and spread them out the length of the board then put the box on the board it will side down the board very easily. The cards kind of act like the moly platelets.
That's the best explanation I've heard for the lubricity of moly.
It does work. Take your pet load and load a few rounds with non-moly coated bullets and load a few with moly bullets and fire them through a graph. Fire the non-molys and watch the velocities, then fire the molys. With each moly shot the velocity will drop until the bore is coated and the velocities stabilize. Less friction, less pressure, lower velocity.
As far as the moly debate goes...I'll just pass along this information and leave it at that.
02-24-2010, 04:55 PM
#10
Fork Horn
Join Date: Feb 2004
Location:
Posts: 215
I've used it in all my rifles for well over 10 years and have had zero problems with it...my target 6PPC has almost 2000 rounds in it and I had the bore scoped last fall and it looks as good as new, no spider cracking in the throat or anything..I will never shoot anything but moly or danzac coated bullets..they cure all Barnes X-bullet fouling problems in my hunting rifles, I've never let one sit for long and clean them all the time and have never had any rust problems or any other thing wrong, everyone get excited about all the black that just never leaves the patch, that's right, it's not supposed to leave..it fills in all the little marks and scratches and little nicks here and there..I can't see why so many people abandoned it so quickly...great stuff, almost as good as Danzac..