Is it just bias for and against molly or do some youse both?

[Regis G]

Yep, another molly question after reading all the posts. When molly is mentioned, it seems that everyone is absolutely "for" or absolutely "against" the use of molly coating.
Is there anyone that has a gun that shoots best with molly and another gun that doesn't like molly? In other words, is there someone who really likes molly coated bullets but has found that one of their guns simply shoots better without molly?

I'm going tomorrow morning to test my 243, 95gr HPBT Sierra with the identical loads with and without molly. That's before I coat the new box of 500.
Thanks,
Regis

 

[M.Stilley]

Yeah. I only use moly on two rifles. The rest use bare bullets. I only use moly when that extra 50-75 fps (or lower pressure for the same velocity) matters. If you don't need to "hot rod" a certain cartridge to meet your needs, then I don't see the need for the extra cost and work.
Not to start a fire here, but in my personal experience bare bullets have produced more consistent targets for me. Ymmv.

 

[mikecr]

The test you speak of, identical loads with & without moly, is meaningless.
If you've read all the posts implied, you should have picked up on the need to load develop specifically for moly coated, which leads elsewhere from uncoated.
And keep in mind that use of moly in a barrel is more committed than for other coatings we use today. That is, once you've laid a moly layer in your bore, it's difficult to undo. It's not like you can just go back & forth in the same barrel.

I only use moly when that extra 50-75 fps (or lower pressure for the same velocity) matters.

You don't understand moly. It does not increase velocity. It lowers burning temperature, reducing both pressure and velocity. More powder is added to recover that velocity. The lower jacket friction provided with the coating helps bullets stay together in hot rods, and well managed moly fouling extends intervals between copper foulouts, and can provide for pre-fouling.
The notions of higher velocity with bullet coatings is a myth..

 

[Regis G]

The test you speak of, identical loads with & without moly, is meaningless.
If you've read all the posts implied, you should have picked up on the need to load develop specifically for moly coated, which leads elsewhere from uncoated.
And keep in mind that use of moly in a barrel is more committed than for other coatings we use today. That is, once you've laid a moly layer in your bore, it's difficult to undo. It's not like you can just go back & forth in the same barrel.


You don't understand moly. It does not increase velocity. It lowers burning temperature, reducing both pressure and velocity. More powder is added to recover that velocity. The lower jacket friction provided with the coating helps bullets stay together in hot rods, and well managed moly fouling extends intervals between copper foulouts.

I expect now that my test will not yield my desired results. And the thorough cleaning necessary between sets. Well, this one has done pretty good with molly so, I'll be sticking with it and coat those 500.
Thanks
Regis

 

[ireload2]

Moly disulfide in the presence of moisture can create sulphuric acid.
I do not use it because I prefer top use my energy on other load characteristics.
If I did use it it would be with carefully controlled experiments with a single rifle.
You might check out others experiences with pitted bores.
http://www.sprinco.com/articles.html

Moly has sulphur in it. I once saw an engineering problem where a large insulator was made of Delrin acetal polymer and was exposed to the exhaust of a Blackhawk helicopter. This insulator was attacked and damaged by the moisture from dew and rain reacting with the sulfur in the helicopter exhaust residue. The solution to the problem was to use a more chemically resistant polymer PET. This was the machined plate version of the plastic used in 2 liter soda bottles. The insulator was about 4 inches in diameter and about 1.5 " thick and there were 4 per helicopter.

 

[Regis G]

Well, I did go to the range this afternoon (96 degrees) and shot the test loads. Each 5 rounds Sierra 95gr HPBT
- 41.8gr IMR4350 Molly coated 3015fps average No coating 3033fps average
- 42gr Win760 Molly coated 3007fps average No coating 3096fps
Before shooting these I warmed/fouled the barrel with 5 shots molly coated 33gr Varget (2650fps).

BTW, With the uncoated Win 760 I got a 0.655 group at 200 yards. Others weren't near that close.
Thanks all,
Regis

 

[M.Stilley]

You don't understand moly. It does not increase velocity. It lowers burning temperature, reducing both pressure and velocity. More powder is added to recover that velocity. The lower jacket friction provided with the coating helps bullets stay together in hot rods, and well managed moly fouling extends intervals between copper foulouts, and can provide for pre-fouling.
The notions of higher velocity with bullet coatings is a myth..

No, sir, you don't understand it. Reducing barrel to bullet friction does nothing with your "burning temperature". Using the same powder charge, this decreased friction lowers velocity 1-2% and peak pressure about 5%. Once you work your load back up toward your original bare-bullet pressure, you will have gained a little bit of velocity, maybe 3%.

I'll stand by my original statement: if you can't use a bigger cartridge, and you have to have that extra 50-75fps, then give some sort of friction reducing bullet coating a shot.

 

[dbramley]

If you were going to coat, why wouldn't you use HBN instead of moly

 

[Capt. Oblivious]

I use moly in all my rifles but for a little different reason than you guys. Here in sunny S Africa we only have a couple off local powders to choose from and most off them are decent but with one problem, we cant get enough powder in most cases (powder isn't "Slow" enough) to fill it up without running into pressure. With the bigger magnum cases WM/RM/LM the problem just gets bigger and your siting with a case and big heavy bullet that you want to use for LR shooting but your only filling 92% of that case with powder and your dying to get your ES in single digits. With Moly and the "side effect" off being able to get a bit more powder in the case im able to get allot off calibers to 100% full and even close to 97-98% full with the bigger magnums. I have only been using Moly for a couple months and for now im very happy with the results. When my current Moly supply runs out I think I will be moving over to HBN

 

[fgregorio]

The test you speak of, identical loads with & without moly, is meaningless.
If you've read all the posts implied, you should have picked up on the need to load develop specifically for moly coated, which leads elsewhere from uncoated.
And keep in mind that use of moly in a barrel is more committed than for other coatings we use today. That is, once you've laid a moly layer in your bore, it's difficult to undo. It's not like you can just go back & forth in the same barrel.


You don't understand moly. It does not increase velocity. It lowers burning temperature, reducing both pressure and velocity. More powder is added to recover that velocity. The lower jacket friction provided with the coating helps bullets stay together in hot rods, and well managed moly fouling extends intervals between copper foulouts, and can provide for pre-fouling.
The notions of higher velocity with bullet coatings is a myth..

M Stilley's observation is deeper than what can be read on a first approach. You can get the extra velocity because you can increase your loads further without signs of pressure.
In my competition rig, I use HBN coated and hoover pointed HBC 155.5gr for a mv of 3144 fps,10 shot es 12 fps sd 4 fps or less. 46.9gr varget, 25 thou off, annealing pre every reload, seating with micro wilson on 21 century hydro seater. Batch order decreasing seating pressure. Most days it goes sub quarter.
Barrel is a hand picked Bartlein 5R 1/11. 28 inch. It started as a 35 inch but the constriction point was found at 28 inch- I said "cut and crown".

 

[fgregorio]

Ah to clarify. The standard similar uncoated proj rig uses 45 gr varget , mv 2980 fps for similar chamber pressure (primer print).

 

[mikecr]

You can get the extra velocity because you can increase your loads further without signs of pressure.

You don't get more velocity without increasing pressure. You increase your load to do that. Moly cools the burn through it's latent heat of vaporization. It's the only friction coating we use that does this.
The proof that friction itself does nothing to change our MV can be seen with use of tungsten disulphide (WS2). It is way way way(+3 other ways) more slippery than moly, and does not change MV or pressure, one bit.

 

[Brians356]

You don't get more velocity without increasing pressure. You increase your load to do that. Moly cools the burn through it's latent heat of vaporization. It's the only friction coating we use that does this.
The proof that friction itself does nothing to change our MV can be seen with use of tungsten disulphide (WS2). It is way way way(+3 other ways) more slippery than moly, and does not change MV or pressure, one bit.

+1
Cooling effect of MoS2 vaporization has been well documented.
-

 

[gunsandgunsmithing]

+1
Cooling effect of MoS2 vaporization has been well documented.
-

Where? I'd like to learn more about this. Can it really be significant in our application? We're not burning moly, we're burning powder..of course, with the exception of some very tiny amount that may burn away from an already tiny amount that it takes to plate a bullet. I'm very curious about this and am serious. Please provide a link or something. I tried a quick search and found nothing relative to our application in firearms. FWIW, I don't shoot moly but have recovered several WS2 coated bullets and most of it stays intact rather than being burned away. Moly may be totally different. That's why I'm asking. TIA--Mike

 

[mikecr]

We're way past moly's heyday.
Can't today, but tomorrow i'll try to dig up something out of an old laptop, or backup drive.

 

[chino1969]

I will never use moly in a custom precision barrel. My reason is simple. A match grade barrel costs approx. $300.00. Add another $200.00 to chamber and fit. I will not introduce anything into that bore the barrel maker does not recommend. To my knowledge, none of the upper tier barrel makers recommend moly. I have shot moly in factory barrels but have laid off the practice. I have a borescope and examine my bores before & after cleaning. Once moly is introduced into a bore it is hard as hell to remove. A match grade hand lapped barrel bore is a glimpse into near perfection. Why change that?

 

[gunsandgunsmithing]

I will never use moly in a custom precision barrel. My reason is simple. A match grade barrel costs approx. $300.00. Add another $200.00 to chamber and fit. I will not introduce anything into that bore the barrel maker does not recommend. To my knowledge, none of the upper tier barrel makers recommend moly. I have shot moly in factory barrels but have laid off the practice. I have a borescope and examine my bores before & after cleaning. Once moly is introduced into a bore it is hard as hell to remove. A match grade hand lapped barrel bore is a glimpse into near perfection. Why change that?

I haven't used moly in years, but I can tell you why I do use WS2. I've won grand aggs with 400 rounds through the barrel without cleaning..more than once...that's why. It reduces fouling to the point where I believe cleaning is more a detriment, long term, than not. I typically clean after a full day of shooting without a drop off in accuracy. With that said, a feel a cleaning rod, jag, etc. is more likely to hurt the bore than anything we put in them. The less I have to do that, the less likely to damage the bore in some way. It's all about what you feel works best for you. I too have a borescope and it and the targets tell me when I need to clean. I've used the same method for several years. It's what works for me. In BR, believe me, if I felt cleaning more would gain me any small amount of advantage..I'd do it more.

 

[mikecr]

There are advantages to WS2 (some over the others) with at least one of them unique:
1. It acts very similar to powder fouling. So much so, that your first shot with it is as likely to be with your best.
2. It cleans right out, just like powder fouling.
3. It does not affect MV or tune over bare bullets.
4. Coated bullets seat with consistent lower friction/force.
5. It acts to extend copper foul-out intervals (like the others).

I've used WS2 for ~30yrs now, or more.
I used it prior to merchandising and fade away as Danzac(always hated this brandnomer).

 

[CJ6]

[QUOTE="mikecr, post: 36838292, member: 106605"Danzac(always hated this brandnomer).[/QUOTE] It (Danzac) always makes me think of a script the Vet would give for a hyper-active dog.

 

[TAJ45]

Ok, I've read abt moly off and on for years, have formed an opinion. I know I did not research the chem end of it like some posters here but still have one question I haven't seen addressed:
If powder is the main cause of throat erosion, wouldnt increasing the charge by the amt needed to regain the original velocity increase throat wear?