The UK's Finest Independent Forum for Shooters and Gun Owners. Est 2010.

I only shoot lead bullets in a .357 Marlin U/L. I often wondered why soft lead bullets are lubricated and harder FMJ's are not. I should probably know this but don't have the faintest idea.

To reduce/prevent fouling.

Does that mean if FMJ's were lubricated it would reduce/prevent copper fouling?

ColinR wrote:Does that mean if FMJ's were lubricated it would reduce/prevent copper fouling?

This is what Moly-coating is.

This could open a real can or works, oomans. We're sure the usual suspects will pop along in a minute to offer their opinions but in the meantime we'll proffer a few facts.

Friction couple between copper and steel = 0.53
Friction couple between lead and steel = 0.41

Thus, on the face of it, for two set ups with equal surface roughness, the lead has less requirement for lubrication...

TattooedGun wrote:

ColinR wrote:Does that mean if FMJ's were lubricated it would reduce/prevent copper fouling?

This is what Moly-coating is.

Well, maybe.... Molybdenum coating on bullets makes them more slippery so the chamber pressure is reduced, this in turn means you can run a cartridge with more powder for the same pressure as an uncoated bullet when doing a like for like comparison. The Viking shoots a 22-6,5x47 Wildcat (22C) so she can run full case capacity of powder for optimal bur yet keep within an MoD range limit of 1000m/sec. This means her chosen bullet is not being over rotated to the point that the jacket separates (Other than on very warm days!)

Some people have also suggested that barrel life is improved with Moly coating however there is some controversy over this and if there is a reduction in copper it is replaced with the Moly which is not the easiest of things to remove without effort. On a personal note as it is me who copper strips the Vikings barrels, I have not noticed a reduction in copper fouling when she shoots coated bullets.

I like your thinking Badger, because that's what I thought.

Ovenpaa wrote:

TattooedGun wrote:

ColinR wrote:Does that mean if FMJ's were lubricated it would reduce/prevent copper fouling?

This is what Moly-coating is.

Well, maybe.... Molybdenum coating on bullets makes them more slippery so the chamber pressure is reduced, this in turn means you can run a cartridge with more powder for the same pressure as an uncoated bullet when doing a like for like comparison. The Viking shoots a 22-6,5x47 Wildcat (22C) so she can run full case capacity of powder for optimal bur yet keep within an MoD range limit of 1000m/sec. This means her chosen bullet is not being over rotated to the point that the jacket separates (Other than on very warm days!)

Some people have also suggested that barrel life is improved with Moly coating however there is some controversy over this and if there is a reduction in copper it is replaced with the Moly which is not the easiest of things to remove without effort. On a personal note as it is me who copper strips the Vikings barrels, I have not noticed a reduction in copper fouling when she shoots coated bullets.

This is interesting. Granted, I'd heard a little about Moly being a pain to remove, so have no real wish to look into it, but from the little I've gleaned, people mentioned that Moly Coated reduces the amount of copper fouling, however takes about 10 shots to coat the barrel uniformly with Moly after a fresh cleaning which makes the break in considerably longer than standard fouling on a barrel.

So, oomans, you put molybdenum coatings on bullets to make them slippery.

Then you find the slippery molybdenum sticks to the barrel and is hard to remove.

Bit bafflin' that one isn't it ?*








* Whilst we're thinking about such things, just how does the Teflon coat stick to a frying pan when it's allegedly 'non-stick' ?

You might like to read http://www.lasc.us/Fryxell_Book_Chapter ... cation.htm