Testing Friction Reduction of Bullet Coatings

[Michael Courtney]

I used some snake oil in my 30/378 Accumark. Did the before and after on the crony, before 180 grnx 114.5 Retumbo 3480 (hot) treated the barrel
then i used 190 grn Berger with 110.5 Retumbo 3460 fps
Groups 3 shot x 3 avereged .54" For me Accuvel works ..

A significant reduction in pressure and less than a 1% reduction in velocity for a slightly heavier bullet, probably indicates a significant reduction in barrel friction. However, it is not evident that the Accuvel rather than the change from a solid copper X bullet to a jacketed lead Berger was the cause of reduced friction. Our testing has shown that solid copper TSX bullets tend to have roughly 50% more friction than jacketed lead bullets. And we believe that the older X bullets without the grooves would have even more friction.

Sound scientific testing requires only changing one factor at a time. Different pressure observations can be caused by different primers, different lots of brass, different temperature between the two tests, different lots of powders, etc. In our friction tests, we have been careful that the only thing we changed was the explicit factor under study. This has allowed us to accurately quantify the friction of different bullets.

Assessing the effectiveness of Accuvel is further hindered by the fact that no scientific data appears to be available, and the company appears to be out of business.

 

[jake50]

A significant reduction in pressure and less than a 1% reduction in velocity for a slightly heavier bullet, probably indicates a significant reduction in barrel friction. However, it is not evident that the Accuvel rather than the change from a solid copper X bullet to a jacketed lead Berger was the cause of reduced friction. Our testing has shown that solid copper TSX bullets tend to have roughly 50% more friction than jacketed lead bullets. And we believe that the older X bullets without the grooves would have even more friction.

Sound scientific testing requires only changing one factor at a time. Different pressure observations can be caused by different primers, different lots of brass, different temperature between the two tests, different lots of powders, etc. In our friction tests, we have been careful that the only thing we changed was the explicit factor under study. This has allowed us to accurately quantify the friction of different bullets.

Assessing the effectiveness of Accuvel is further hindered by the fact that no scientific data appears to be available, and the company appears to be out of business.

Sorry there was a small misprint it was a 180 Nosler BT not Barnes.
I have used it also on my 243 same thing happened . Yeh the web site no longer exists , but i still stay in contact with the inventor Funny thing when it worked i didnt want to tell anyone ,just to keep it to myself. I have used Militec-1 in one of my other rifles it did nothing . All the differing primers etc would not increase or decrease velocity to such an extent, all bullets were seated the same OAL same primer etc. As i said i am happy it works for me.
Cheers

 

[Michael Courtney]

Sorry there was a small misprint it was a 180 Nosler BT not Barnes.
I have used it also on my 243 same thing happened . Yeh the web site no longer exists , but i still stay in contact with the inventor Funny thing when it worked i didnt want to tell anyone ,just to keep it to myself. I have used Militec-1 in one of my other rifles it did nothing . All the differing primers etc would not increase or decrease velocity to such an extent, all bullets were seated the same OAL same primer etc. As i said i am happy it works for me.
Cheers

The 180 NBT has a much thicker jacket than the Berger, so I would expect more friction. It also has a harder lead core (harder lead alloy) which also tends to increase friction in the bore.

Also, using a different primer can cause several different effects:
1) We've tested primers that increased barrel friction by 50% or so.
2) Primers with softer cups will appear to show higher signs of pressure because they are more distorted even if the pressure is the same.
3) Retumbo is an unusual powder. Changing a single component (bullet or primer) can have more pronounced effects than other powders in the same range of burn rates.

Sound science does not allow for confidence drawn from observations ascribing causality to one factor when multiple factors were changed. Even if one factor seems more likely than others, the confidence level will be low. Furthermore, the ability for observations to be repeated by independent parties is important to the scientific method. The lack of ongoing product availability make further testing difficult with regard to friction redicing claims. It also makes discussion more academic and not very relevant to shooters because even if the stuff works, they can't get it.

 

[jake50]

I wasnt trying to market it for the maker , i just said it works for me..

 

[Michael Courtney]

I wasnt trying to market it for the maker , i just said it works for me..

Cod liver oil really works for me.

Ever since I started taking cod liver oil, stopped smoking, and lost 50 lbs, I've shaved 2 full seconds off my time in the 100 yard dash.

Women find me more attractive too.

That cod liver oil really works for me!

 

[jake50]

Cod liver oil really works for me.

Ever since I started taking cod liver oil, stopped smoking, and lost 50 lbs, I've shaved 2 full seconds off my time in the 100 yard dash.

Women find me more attractive too.

That cod liver oil really works for me!

Good,, stick to it.

 

[Outlaw6.0]

Cod liver oil really works for me.

Ever since I started taking cod liver oil, stopped smoking, and lost 50 lbs, I've shaved 2 full seconds off my time in the 100 yard dash.

Women find me more attractive too.

That cod liver oil really works for me!

LOL! Here I was thinking you were all business....


I would like to get some info in regards to the Monometal bullets (specifically Barnes) as I shoot a BUNCH of those. I believe it was your first post discussing 223 projectiles. If I recall correctly, the barnes TSX experienced a friction reduction of less than 1% with the HBN coating correct? Any hypothesis on why that would be? Lack of bearing surface maybe?

 

[Michael Courtney]

LOL! Here I was thinking you were all business....


I would like to get some info in regards to the Monometal bullets (specifically Barnes) as I shoot a BUNCH of those. I believe it was your first post discussing 223 projectiles. If I recall correctly, the barnes TSX experienced a friction reduction of less than 1% with the HBN coating correct? Any hypothesis on why that would be? Lack of bearing surface maybe?

None of the lubricants tested reduced the friction in the Barnes bullet more than 1%, and MS2 and WS2 actually increased the friction. With the 55 NBT, HBN decreased the friction by 15%, while WS2, MS2, and Lubalox all increased the friction. For the 62 BFB, the coatings decreased the friction by 7% to 15%.

Based on these observations, an educated guess might be that bullets with thinner jackets and softer cores might tend to get more friction reductions by coating.

I'll leave it as an open question why the Barnes bullet got so little benefit. One hypothesis is that it is the smaller bearing surface due to the grooves. Another hypothesis is that it is due to the hardness of the copper and larger normal forces between the bullet and barrel.

We have repeatedly observed that steel core bullets and solid copper bullets tend to have much larger friction (uncoated) than jacketed lead bullets, and jacketed lead bullets with thin jackets and soft lead cores tend to have less friction than "stouter" bullets with thicker jackets and harder lead cores.

It has also been reported to us by other parties in private communication that attempts to use coatings to reduce the friction of (ungrooved) solid copper bullets have been unsuccessful. This is consistent with the observation that Barnes itself was once coating their bullets but has since stopped marketing coated bullets.

I've also seen data (not as careful a study as our published friction work) that suggests that solid brass bullets (uncoated with grooves) have friction closer to solid copper bullets (uncoated with grooves) than to thin jacketed soft core match type bullets.

Don't get me wrong. I'm a big fan of solid copper bullets, and especially the Barnes TTSX design and I'd recommend them highly for a number of applications. My family's elk loads in both 25-06 and 30-06 use Barnes TTSX bullets. But the increased friction is a trade-off of using solid copper bullets, and we are careful to use data developed specifically for solid copper bullets and carefully watch for pressure signs when working up loads. In .308 Win, I have been unable to work up a suitable load for solid copper bullets that was fast enough for the range capabilities I desired.

 

[Outlaw6.0]

I still utilize some of the Barnes XLC coated bullets (6.5- 140's). They discontinued the manufacture of the XLC at roughly the same time (running from memory here) as the original X bullet. Coincidence?

With solid copper acutally being softer than the guilding metal used in the jacket of todays "normal" bullets, I would tend to think you would see more compression/deformity as the bullet enters the lands? I understand difference in thickness of a jacket vs full copper construction but one would think a softer surface will deform faster & easier.


Maybe i'm crazy....


gun)

 

[barnesuser28]

I still utilize some of the Barnes XLC coated bullets (6.5- 140's). They discontinued the manufacture of the XLC at roughly the same time (running from memory here) as the original X bullet. Coincidence?

With solid copper acutally being softer than the guilding metal used in the jacket of todays "normal" bullets, I would tend to think you would see more compression/deformity as the bullet enters the lands? I understand difference in thickness of a jacket vs full copper construction but one would think a softer surface will deform faster & easier.


Maybe i'm crazy....


gun)

Since lead is much softer than copper i think when a gilding metal jaketed bullet enters the lands it compresses the lead core very slightly where as a solid copper bullet wouldnt compress as much.

That is my hypothesis but i am more than likely wrong though.

 

[Outlaw6.0]

Since lead is much softer than copper i think when a gilding metal jaketed bullet enters the lands it compresses the lead core very slightly where as a solid copper bullet wouldnt compress as much.

That is my hypothesis but i am more than likely wrong though.

Then you get into the mechanics of compression which I know nothing about of course. my thought process is, when you compress something it has to go somewhere right? When your lead core is totally encapsulated in a jacket, where can it go?

 

[barnesuser28]

Then you get into the mechanics of compression which I know nothing about of course. my thought process is, when you compress something it has to go somewhere right? When your lead core is totally encapsulated in a jacket, where can it go?

Think air compressor. All the air just gets pushed closer together.

If the lead cant compress enough it can just move forwand into the extra space in the nose of the bullet providing there is room which in most cases there is.

 

[Outlaw6.0]

Think air compressor. All the air just gets pushed closer together.

If the lead cant compress enough it can just move forwand into the extra space in the nose of the bullet providing there is room which in most cases there is.

That isn't going to fly Lead holds the second most density of common metals next to gold, you are in no way going to compress lead, at least in our application. Now, of course you can easily displace it, that is the wonder of the material. From a projectile standpoint, not only do you have to essentially crush the jacket of the bullet (for lack of better terminology) but you have also got to displace enough of the core to allow the depression of jacket. Now, wouldn't it require less effort to displace that extra material into the bands along the shank of a Barnes bullet especially when the material you are working with is softer?


My assumptions are pure hypothetical SWAG of course

gun)

 

[barnesuser28]

That isn't going to fly Lead hold the second most density of common metals next to gold, you are in no way going to compress lead, at least in our application. Now, of course you can easily displace it, that is the wonder of the material. From a projectile standpoint, not only do you have to essentially crush the jacket of the bullet (for lack of better terminology) but you have also got to displace enough of the core to allow the depression of jacket. Now, wouldn't it require less effort to displace that extra material into the bands along the shank of a Barnes bullet especially when the material you are working with is softer?


My assumptions are pure hypothetical SWAG of course

gun)

Oh ya i forgot that.

Ya you make good points and you are probably right. I bet Michael will have an answer.