Testing Bullet Lube at 3000 fps

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Testing Bullet Lube at 3000 fps

Postby mtngun » Sun Oct 23, 2016 4:59 pm

I'm down to my last few globs of the discontinued Rooster HVR lube so I have no choice but to find a new favorite lube. Previous tests have given me a pretty good idea what will work and what won't, but nonetheless I'm going to conduct even more tests and let the results guide my final choice.

The plan is to shoot ten 10-shot groups with each lube at 3000 fps, without cleaning in between the 100 shots. Why? Because "cast bullets at 3000 fps has a nice ring to it, don't you agree?

Even 100 shots each may not be enough to prove a statistically significant difference between some lubes, nonetheless "100 shots each" has a nice ring to it. :cool:

The tentative list of lubes to include in the test:

-- HVR as the previous "gold standard"
-- LBT Blue (the so-called hard version)
-- White Label Carnuba Red
-- White Label Commercial 190 degrees
-- White Label 2500 (preferred by Larry Gibson for hi-vel use, last I heard)

I may add one or two more lubes to the list, but it's not feasible to test every lube out there unless I win the lottery and retire. :D Once a new "gold standard" lube is chosen, I can always use it to do a one-on-one comparison with other lubes.

I thought about giving homebrew lubes another whirl. I've learned a few things since my last attempt at homebrew lube, and I suspect now I could equal HVR without too much difficulty. However, that could take some time and I never seem to have enough time. Also, I don't mind paying a few bucks for storebought lube because it's a minor cost compared to what I spend on powder, primers, barrels, etc.. I can always revisit homebrew lube later if the spirit moves me.

It takes the better part of a day to load and shoot 100 shots, allowing the barrel to cool for a minute between each shot and for 10 minutes or so between groups. At any rate after 100 full throttle shots at the bench I've had enough, so this comparison test may take several weeks or even months, depending on how often Mr. Murphy visits my range.

For today I shot HVR. This will be the control load, the "gold standard" against which the other lubes will be compared. I'm hoping one of the other lubes will prove to be at least as good as HVR.

The test rig and its control load:

-- Remington M700 switchbarrel bench rifle
-- Pacnor 6-groove 14" twist 7BR which I have discussed in another thread
-- 34.0 gr. WC845. It's not my favorite powder but it was sitting on the shelf, and that counts for something. :D
-- CCI #450 primers
-- 100 gr. GC spitzer
-- J.R. brand reclaimed shot oven treated @470F
-- nose sized to match the taper of the throat
-- final sized 0.284" (the barrel's groove is 0.283")
-- seated for 0.015" jam

Today's target. Group #0 was a warm-up group using wheelweight alloy, while groups #1 - 10 are the "official" groups using reclaimed shot. This will be the standard that other lubes are expected to at least equal.

I repeat for emphasis -- the barrel was not cleaned between groups! At the end of the day I pushed one patch through with Ed's Red, and the only reason I did that was to deter corrosion, not because the barrel was dirty. There was nothing on the patch other than some black carbon. If the barrel had been fouling we would expect groups to open up as more shots were fired, but that didn't happen. If anything groups became smaller and more consistent as more shots were fired, indicating a stable barrel condition. Pacnor makes a good barrel, and HVR is a good lube.
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The cartridge as loaded today, and with today's luckiest group. If I could shoot groups like that every time I'd be a happy caster! 8-)
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My chrono has no printer so this is as close as I can come to providing tangible proof of the velocities.
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Taran stats and velocity stats. "D10X" is what Taran predicts the average 10 shot group will be with that load. Some of the Taran group sizes are a few hundredths different than my field measurements with a ruler and that's due to normal measurement tolerances.
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Re: Testing Bullet Lube at 3000 fps

Postby mtngun » Wed Oct 26, 2016 9:47 pm

Update: Grey's #24 will be included in the shootout, thanks to a CBA member who volunteered to donate a sample. The good thing about Grey's #24 is that it is well known and respected in CBA circles, so that makes it a good reference point. The bad thing about Grey's #24 is that it is no longer available, so if it should "win" the shootout, that won't help us one iota in our search for a lube to replace HVR. :?

Thoughts on leading and on so-called "lubrication": this particular 7BR barrel does not lead appreciably with HVR, not even at 3000 fps. But it is possible that some of the other lubes in this test may lead, so let's go ahead and talk about leading.

I have observed at least 3 distinct kinds of leading in various firearms over the years:

1) leading near the peak pressure point due to failure to seal. In revolvers, this often shows up in the forcing cone, while in rifles it may appear 2" - 4" from the breech. Typically it leaves lead in the corners of the rifling grooves, and this lead can be difficult to remove, almost as if it were soldered in place, which may well be the case. This "peak pressure" leading is caused by hot gases blowing past the bullet. With a plain base bullet, the high combustion temperatures may actually melt the corner of the bullet base. There are several possible solutions, like coatings, gas checks, better fit, etc., but with regards to bullet lube, I think this is where a "sealant" type bullet lube can help, by functioning as a tough o-ring rather than as a slippery lubricant. The catch 22 is that the best "sealant" lube may not be the best lube in other respects -- an example being my experiment with Permatex #2 gasket sealer as a bullet "lube," working surprisingly well in a snub nose revolver but making a mess in a rifle.

2) streaks of lead near the muzzle due to the bullet actually beginning to melt due to sliding friction and/or heat from combustion gases. Whereas "peak pressure" leading is worse in the corners of the grooves, sliding friction leading may be worse on the lands. Sliding friction will be highest at the muzzle because velocity is highest at the muzzle. Also, the bullet temperature will be highest at the muzzle due to the accumulative heat absorption from both sliding friction and from the base's exposure to the hot gases. Pressure has fallen dramatically by the time the bullet reaches the muzzle, so the "sealant" qualities of the lube matter less while the lubrication qualities matter more.

A popular theory is that leading at the muzzle means the bullet was "running out of lube," but I find it easier to believe that the bullet simply got too hot. Of course those two things may be related -- if friction was high because the lube failed to reduce friction for whatever reason, the friction will create more heat! But on the whole, I have not noticed that any particular quantity or quality of lubricant is required to avoid leading at the muzzle, the lube just has to exist and it just has to possess some modest lubricating qualities.

In addition, it may be that a bullet lube acts like a "coolant." Harold Vaughn, in "Rifle Accuracy Facts," demonstrated that the carnuba wax used in conjunction with moly coating effectively cooled the hot gases because of the energy required to vaporize the wax. One can imagine that this vaporization process may create a thin layer of cooler gases at the bullet base as the molecules of lube shed by the bullet are vaporized.

3) a soft grey "wash" or mist, typically most visible near the muzzle. I believe this is lead that was vaporized by hot gases -- most likely there was some gas cutting near the peak pressure point. The vaporized lead was then carried along with the hot gases down the barrel until combustion temperatures drop enough to condense the vapor, leaving a mist or a "wash." The grey "wash" is easily removed with a wet patch.

Our understanding of cast bullets continues to evolve, and I reserve the right to change my mind, but at this moment I believe that a bullet lube is firstly an o-ring and secondly a lubricant. Too much emphasis has been placed on the lubrication qualities -- hence we have lubes with slippery ingredients like jojoba oil, castor oil, Mobil One, moly, etc. -- and not enough emphasis on the o-ring qualities, which require toughness and tackiness.

There is nothing about HVR that suggests it has exceptional lubricating qualities -- it is a hard, tough, and tacky lube, not a slippery lube -- yet it works very well. Likewise, Alox is viscous and tacky, but not particularly slippery.

Lube Stars: another popular theory is that an adequately lubricated bullet should leave a "lube star" at the muzzle, Yet HVR does not leave a lube star, so I do not believe in the "lube star" theory.

Lube Purging: another theory is that residual lube may build up in the barrel until finally a bullet comes along and pushes the residual lube out of the barrel. According to the theory, the unstable bore condition results in fliers. Well, I agree that a stable bore condition is desirable, but when I do bore scope inspections I don't detect gobs or streaks of residual lube in my barrels. In fact, it stands to reason that any residual lube would be consumed by the the hot combustion gases.

That said, I have, in certain loads in certain firearms, observed residual lube in the neck area of the chamber, though not in the barrel itself. Have you ever seen a fired case with a streak of lube on the neck? Well, I have. What happens is that as the bullet enters the throat and is engraved by the rifling, the lube that is displaced by the rifling is forced to go somewhere .... and the only place it can go is backwards, squirting lube into the neck area, and sometimes in the entrance of the throat. I suspect that happens often but that most of the time the "squirted backwards" residual lube is consumed by the hot gases, and only under certain circumstances does residual lube survive. When the next round is chambered, the residual lube may make it a tight fit, or it may push the bullet to one side causing a flier. For the most part this "lube squirting backwards as the bullet engraves" does not seem to be not a common problem,

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Re: Testing Bullet Lube at 3000 fps

Postby mtngun » Sat Oct 29, 2016 4:35 pm

Today we continued the lube shootout, this time with White Label Carnuba Red. Range conditions were 10 - 15 mph wind, partly cloudy, and occasional mild mirage -- pretty much the same as last week.

Carnuba Red averaged 1.41", compared to 1.48" with HVR. 3 groups were MOA or better, though only barely.
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Disclaimer: it's sometimes impossible to pick off every bullet hole for the mean radius calculation when the group is one ragged hole, so when that happens guesswork comes into play. But the one ragged hole problem is the kind of problem I want to have.
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Summary to date:
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Re: Testing Bullet Lube at 3000 fps

Postby mtngun » Sun Oct 30, 2016 2:09 pm

The lube shootout continues with Gray's #24, which is no longer in production but I included it in my shootout because it is highly regarded in the benchrest community. The best it could do was a lousy 1.10".
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Stats:
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And the shootout highlights to date:
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Was Gray's 24 significantly worse than HVR? According to a student's T-test calculation based on their mean radius data, there is a 76% probability that Grays is less accurate than HVR, and an 85% probability that Grays is less accurate than Carnuba Red.

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Re: Testing Bullet Lube at 3000 fps

Postby mtngun » Tue Nov 01, 2016 6:32 pm

Continuing the 3000 fps lube shootout ..... First up, White Label Commercial 190 Degree. This is a "commercial" hard lube as opposed to a high-performance hard lube. The commercial hard lubes are formulated to be non-sticky while the better high-performance hard lubes are formulated to be "tough & tacky".

I've had good luck with some "commercial" hard lubes in a revolver, but not so much in high velocity rifle. Today was no exception.

FYI starting with a cold, clean barrel ("clean" meaning wiped with Ed's Red two days ago) the first fouling shot landed 3" high, the 2nd fouling shot landed 1" high, and the 3rd shot landed within the normal POI zone. Different barrels have different personalities but that sort of start-up behavior seems typical for this barrel regardless of lube.

Groups #1 and #2 were fired without cooling between groups. Then I switched to my usual routine of allowing the barrel to cool while I loaded the next 10 rounds (approximately 10 minutes). Groups #3 - #5 threw the first shot high, presumably due to letting the barrel cool for 10 minutes.

I have observed this "first shot high" phenomena with other lubes, including HVR, but Commercial 190 seems to do it to an extreme. So I altered my routine, shooting groups #6 - #10 without cooling between groups. That eliminated the "first shot high" fliers. Nonetheless Commercial 190 turned in an overall poor performance, not particularly surprising for a "commercial" lube.

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Switching to LBT Blue .... this is the so-called "hard" Blue, though it's not very hard compared to a true hard lube. It's more of "medium" hardness in my book.

During the first group with Blue (#11), I screwed up a shot by failing to return the rifle to battery. It was quite obvious because the rifle nearly fell out of the front rest when it recoiled, and the bullet was a wild flier. I don't like to dismiss fliers but in this case it was definitely operator error, so I disregarded that shot and fired a make-up shot.

Blue turned in several fine groups, but it also turned in some poor groups. :( Overall, Blue did much better than I expected, considering it has been a poor performer for me in the past, particularly in a revolver.

Today's luckiest groups:
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Today's Stats:
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Summary:
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T-Tests using mean radius for each group:
-- 98% sure that Commercial 190 is less accurate than Rooster HVR.
-- 99% sure that Commercial 190 is less accurate than Carnuba Red.
-- 69% sure that LBT Blue is less accurate than Rooster HVR.
-- 81% sure that LBT Blue is less accurate than Carnuba Red.

As my shooting mentor used to tell us when we scored our targets "Read it and weep, Gentlemen." :lol:

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Re: Testing Bullet Lube at 3000 fps

Postby mtngun » Sat Nov 05, 2016 11:02 am

Today we tested White Label 2500. No coating, just an old fashioned lubed bullet. Including the 3 fouling shots (2 at the start, 1 after pausing to reload 50 shells) 103 shots were fired without cleaning the barrel.

I'm guessing that the wild flier in group #9 was due to some defect in the bullet, not due to a lube problem, but nonetheless I just report the facts and you can judge for yourself. If you disregarded group #9 then the average group would have been 1.42", a tie with Rooster HVR and White Label Carnuba Red. At any rate 2500 did a respectable job.
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The lucky group of the day, with an unlucky "heartbreaker" shot at 12 o'clock.
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Stats:
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Summary for all lubes to date, listed from best to worst. Note that White Label 2500 has the least velocity variation so far. :)
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Taran overlay of all 100 shots. The overlay is only appropriate when every group has the same point of impact. If the POI changes because of scope adjustments, lighting, mirage, barrel heating, etc., then the overlay is no longer appropriate. Most of the time the POI does in fact shift a little from group to group for whatever reason, so I normally don't use the overlay. Well, today's groups had nearly the same POI, though not quite, so just for fun I did the 100 shot overlay.
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Student T-Tests based on the mean radius data for the 10 different groups:
-- 30% sure that White Label 2500 is less accurate than Rooster HVR.
-- 43% sure that White Label 2500 is less accurate than Carnuba Red.

In other words, we aren't sure that White Label 2500 is significantly less accurate than HVR or Carnuba Red.

I've decided to add White Label BAC to the the shootout.

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Re: Testing Bullet Lube at 3000 fps

Postby mtngun » Sat Nov 12, 2016 4:46 pm

Today we tested White Label BAC, which is a blend of the NRA formula plus Carnuba Red. The maker describes it as:
This lube is a mix of my Carnauba Red and 50-50. It gives performance similar to Carnauba Red, but does not need a heater. Slightly softer than the 2500+ lube.

But .... the sample of BAC they sent me is what I would call a "medium" hard lube. It was harder than the 2500 lube and it would require a heater. I'm not complaining, I'm just stating the facts.

According to the meter in my back pocket, BAC is the tackiest lube that I've ever encountered, and I consider that a good thing.

Aaaand .... it appears that BAC won the lube shootout.
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The luckiest group of the day:
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Stats for White Label BAC:
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Summary for all lubes, listed from best to worst:
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Student T-Test Results for BAC, based on the mean radius for the 10 groups:
-- 56% sure there is a difference between HVR and BAC (that's too close to call).

-- 44% sure there is a difference between Carnuba Red and BAC (not significant).

-- 66% sure there is a difference between White Label 2500 and BAC (probably significant).

So it's a virtual tie between Carnuba Red and BAC.

Correlation Between Velocity Variation and Accuracy ?
A scatter plot of %velocity standard deviation vs. mean radius doesn't seem to show a correlation.
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Concluding Thoughts:
-- there was no significant leading with any of the lubes. Folks, high velocity per se does not cause leading.

-- accuracy averaged 1.5 MOA for the 700 shots fired in this test. :cool:

-- the accuracy differences between lubes were small and easily overshadowed by the group-to-group variation. Unless you fired 100 shots with each lube and did statistical analysis, you might not notice a difference in accuracy.

-- while conventional CB wisdom tends to diss hard lubes, the "tuff & tacky" hard lubes were the top performers. It's the non-sticky commercial lubes that give hard lubes a bad name.

-- there is no pressure data for the WC845 powder used in this shootout, so I can only guess that pressures were 50,000 psi or more judging by Quickload estimates with similar powders like H335 and WW748. The high pressure did not seem to hurt accuracy. I agree with some other hi-vel experimenters that accuracy at high velocity is limited mainly by RPMs acting on imperfectly imbalanced bullets. There are other things that can go wrong, but those other things are fixable.

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Re: Testing Bullet Lube at 3000 fps

Postby mtngun » Sat Nov 26, 2016 8:36 am

Update: after using BAC for a while in my lubrisizer, I have settled on a heater setting of 35C (95F). The maker claims no heater is required and that's probably true if you are operating out of an un-airconditioned garage in the South where the ambient temperature is 95F. :lol:

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Re: Testing Bullet Lube at 3000 fps

Postby Bjornb » Tue Dec 20, 2016 2:01 am

Lube is about the only area where I'm not in 100% agreement with Larry Gibson. When I first started shooting HV in 2014 (using the Goodsteel/Gibson 30 XCB cartridge and bullet), White Label 2700+ quickly established itself as the go to lube, shooting more consistent groups than 2500. Love your test; wish all shooters would use your scientific approach.


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