Your input desired on design of barrel friction experiment with bullet coatings

[Michael Courtney]

We've developed a method to accurately determine the average frictional force between the bullet and the rifle bore that is accurate within 1-2% and requires about 20 test shots to determine the friction of a particular bullet/coating/bore combination.

Naturally, our next inclination is to quantify the barrel friction resulting from different bullet coatings: HBN, Moly, and WS2. We are leaning toward testing each coating in each of two bullet designs, a conventional jacketed lead bullet and a solid copper bullet in our .223 test rifle. Of course, the rifle barrel will need to be thoroughly cleaned when moving between coatings and before beginning.

A few questions, if you are willing to lend your advice to our experimental design:

1. Should we also test lubalox, the Combined Technology coating? This would constrain our design to one of the .224" bullets available from the factory with this coating. We would also obtain the equivalent uncoated Nosler ballistic tip and get them coated with the other three coatings. Frankly, we'd prefer not to test lubalox, because it locks us into the ballistic tip, and we'd rather test a match bullet from Sierra, Berger, or Hornady. On the other hand, we do think Nosler might be exaggerating the friction reducing claims of lubalox and it would be nice to debunk test the claim.

2. In order to enhance uniformity (because we have so little bullet coating experience), we plan to send the bullets to NECO for moly coating and SSS for HBN. Is there a commercial service that offers WS2 coating, or do we need to roll our own here? Perhaps you can suggest someone with experience coating bullets with WS2 who might be willing to coat a couple of boxes for us. Is WS2 even still used as a common bullet coating? Is it a waste of time to test it, or is there interest?

3. Our .223 Rem test barrel has a 1 in 12" twist which limits us to bullet weights up to 69 grains at our test facility. (We can shoot heavier bullets because of the thin air up here.) Is there a particular match bullet you'd recommend. A bullet with the most uniform bearing surface would be optimal, because preliminary testing (uncoated bullets) suggests that bearing surface has an impact on friction, and it would be optimal to minimize confounding factors so we can emphasize the effects of the coating.

Of course, any other insight or advice you can offer would be greatly appreciated.

 

[necchi]

Welcome to the forum, you'll have an opportunity to share with and hear from some of the top shooters and loaders in the country here.

Without any more info than you have supplied here I'm already sceptical of any information or honestly represent the data you compile because of this statement;

On the other hand, we do think Nosler might be exaggerating the friction reducing claims of lubalox and it would be nice to debunk test the claim.

It seems you already have a bias opinion and goal in mind with your new found method and with that kind of mind set actual data can be scqued in favor of a predetermined goal.

you do have an option of deleting this post and rewriting it if you look in the upper corner of your original post;
http://forum.accurateshooter.com/index.php/topic,420319.0.html

 

[Michael Courtney]

Having a hypothesis that a marketing claim is not supported with data is not the same as having a bias.

What is our basis for the hypothesis that lubalox does not significantly reduce barrel friction?

1. The manufacturer has been making the claim for at least a decade but has not published any data in support of it.

2. Bullet coatings that reduce friction such as moly and HBN usually result in higher max loads. Nosler publishes a lot of load data for lubalox coated bullets, but to my knowledge, the max loads they publish for lubalox coated bullets are the same as they publish for uncoated bullets. If the coating reduced friction, the max loads would be higher for coated bullets.

3. Independent measurements from both our lab and from Bryan Litz shows that this company tends to publish BC claims significantly higher than those independently measured.

 

[Michael Courtney]

I would like to know who "we" are ?

www.btgresearch.org

We've published ballistics work in Precision Shooting, Varmint Hunter Magazine, Applied Acoustics, WSTIAC Quarterly, Medicine, Science, and the Law, and Neurosurgery, among others.

 

[necchi]

2. Bullet coatings that reduce friction such as moly and HBN usually result in higher max loads. Nosler publishes a lot of load data for lubalox coated bullets, but to my knowledge, the max loads they publish for lubalox coated bullets are the same as they publish for uncoated bullets. If the coating reduced friction, the max loads would be higher for coated bullets.

Welcome to the world of hand loading as done by the general public in a country rampant with litigious lawyers and the corprate lawyers that maneuver to avoid litigation.

A short study of load data from as little as 10 years ago to what's found in current load manuals and widely available on the internet will show you max loads have gradually become lower and lower.
We/They simply can't make everything idiot proof. If you spend anytime at all on loading forums such as this, you'll see first hand many "new to the hobby" individuals will simply cruise the internet for a few days and feel they will be proficient with grandpa's old loading tools and immediately seek "max load" data for a gun that may not be in pristine condition.

The industry suppliers have learned long ago the hobby is loaded with Bubba and Clem backyard ballistitions.

In summary,
If you look at a Nosler load book you'll see the data is the same for coated and uncoated bullets,, Why? Simply because it's safe.
It's up too the individual loader to proceed with caution above listed Max loads to seek for higher velocity, range and accuracy all the while looking for and understanding the the pressure signs and dangers possible for the gun and individual physical injury.
It's not a common practice to advise to anyone to load over max at any time. Many experienced loaders do indeed go over listed max loads frequently, but you'll seldom see it posted or advised.

Good Luck, I for one simply won't shoot any "lubed" bullets. I don't like what the stuff does to my bore. Any gain for the typical sportsmen or Bench shooter is less than the PITA it is to clean up. That of course is my humble opinion and others will be different.
Not All, Tournament winning shooters and successfull sportsmen use lubricated bullets,

 

[Michael Courtney]

I started reloading 14 years ago and have handloaded a variety of coated and uncoated bullets, keeping careful records of my results. Some of the material in reloading manuals can be attributed to liability lawyers, and this might be the case with the max loads for lubalox being the same as for uncoated bullets. However, it might also be that lubalox does not reduce barrel friction significantly enough to increase the max load. Consider a previous thread on this forum:

http://forum.accurateshooter.com/index.php?topic=3746450.0

FYI: I called Nosler and they said coefficient of friction (with lubalox) should be identical to copper.

My experience is that lubalox and moly do add significantly to the cleaning chores, especially when switching back to uncoated bullets and chasing small velocity spreads. However, our research also shows that many uncoated bullets lose 200 to 1000 ft-lbs of energy to barrel friction, so coating bullets offers potential opportunity for significant increases in muzzle energy if the energy lost to barrel friction can be significantly reduced.

 

[RDavies]

All the political and legal mumbo jumbo aside, I,m keen to hear your findings, not so much for getting more velocity, but for how long these coatings can increase time between cleaning. Something to keep in mind is that some barrels with shoot 100 rounds of naked bullets and still retain accuracy, while others are super accurate for 15-20 rounds, then drop off. Testing only a few barrels might not give a valid comparison.

 

[KevinThomas]

cr500 brings a very relavant point to the table that almost no one ever talks about; how many "naked" rounds can be fired before there's an actual degradation in accuracy. We see claims that a bore needs to be cleaned every 20-25 shots to maintain peak accuracy. While this may be true where benchresters are concerned (and I'm not fully convinced of that), it simply isn't the case for the vast majority of shooting that the rest of us do. Even competitive shooting. Highpower shooters routinely fire a hundred rounds or so before they even have a chance to clean their bores, and the last strings of fire (600 yards) are normally the ones that place the highest demands on accuracy. Yet, the accuracy remains intact.

I'll go out on a limb here and say that I think there was absolute truth to the 20-25 rounds statement when it was first voiced by Townsend Whelen, Julian Hatcher and the other great gunwriters of the period when cupronickle was the standard jacket material for bullets. Since the introduction of 95/5 gilding metal and its becoming the defacto industry standard, I think the original figures have been parroted by gunwriters ever since, regardless of it's validity. I believe Derrick Martin once went an entire season without cleaning his rifle, and he continued to shoot High Master scores (97%+ average). Personally, I'm convinced the whole cleaning obsession is greatly overblown these days.

 

[necchi]

Good points,
Experience with my guns and cleaning is,
Each gun is unto itself unique.
It may be hard to quantify what's best for "clean" for "all guns" from a single experiment.

Some Gentleman are just good shooters, it's a hard lesson when you try to replicate everything a good shooter has, then hand him your gun, and watch as he shoots it better than you.

 

[expiper]

I have used WS-2 for several yrs...started with Danzak then bought it from source in Canada......no problems with any of it .....still shoot the same and clean the same .....the bore seems to be less copper fouled after 50-60 shots....so there is less to clean out!!.....in my "backyard ballistician" estimate it slows bbl wear and minimizes fouling.....didnt do ii to attain more vel. or prevent cleaning ,,,,just to make things easier on bbl wear and tear....contact me off line if you want....Bubba...(aka Roger)

 

[CPorter]

I have coated bullets with all three lubricants and in my opinion ws2 is probably the better lube. It sticks the the bullet better that moly and seems to be easier to get more consistent results than with hBN. Both ws2 and hBN seem to clean out of the barrel easily but hBN is the least messy.

Test them all and if you have the inclination try mixing. One test that might be beneficial to all is how well each one bonds to copper and steel using the same method. Since we lube bullets it should logically follow that the one that sticks to copper best would have superior lubricity.