Residual lube in grooves during flight affect accuracy?

[geargnasher]

Cast boolits "go to sleep" same as any other boolit. A typical round-nosed, gas-checked .30 caliber is usually quiet by 3-400 yards, then it hits the subsonic transition and all goes to heck again. Most guys aren't shooting them that far for a number of reasons, including expectation levels or loading ability.

I've proven over and over again that lube jettison is critical to fine accuracy by doing accuracy comparisons between slightly modified versions of the same lube. For example, I have a "summer" version of Felix lube, which is simply the original recipe plus a teaspoon carnauba wax. This lube won't group quite as well in several of my rifles in cold weather (below 50 degrees) no matter how hot the barrel because the lube isn't coming off at the muzzle any more. Lube flecks are often visible on 100-yard targets. Deleting the Carnauba and adding a tablespoon of vaseline or ATF completly takes care of the issue, accuracy returns, and the lube flecks disappear. The winter lube starts causing "purge flyers" about every three or four shots predictably in hot weather due to, I believe, the lube being "too slick". Point-blank jettison tests and lube recovery (collecting the spatter off of shiny posterboard and weighing it) usually yield about the same recovery as the summer formula does in warm weather. The guns shoot the same, from first shot through long strings, hot or cold, same exact load and components, with only a tweak to the lube and the observable difference in lube spatter recovery. I've done it enough to pretty much conclude that if the lube isn't leaving the boolit, it spoils accuracy, and that whether the lube does or doesn't all leave at the muzzle is primarily a function of the lube's viscosity.

Gear

[44man]

Bullets going to sleep is certainly believed in by many bench rest shooters and high power competitors.

It is true! I have had a lot of experience with it during my varmint and IHMSA days. It can be seen through a good scope. Even a 240 gr bullet from a model 29 does it, just going to a 250 gr will stop it.
It is the result of over spin.
Cast BR shooters usually use a slower twist for the closer ranges.
A faster twist is better for real long ranges. They really do go to sleep at some distance and close range groups are larger then long range.
I liked the 220 Swift over the 22-250 because of the twist. I could shoot a heavier bullet farther while the 22-250 wanted a lighter bullet.
The Swift never shot good 100 yard groups but it could head shoot chucks at 600 yards. My sight in distance was 350 yards then it was easy to dial for distance with the big Balvar 24 scope.
A gun like this is very hard to work loads at 100 yards.

[btroj]

Exactly!
Shooting 200 yard reduced course highpower matches I learned that a lighter bullet often shot tighter groups than the heavier ones. Go past 300 yarss and things reversed.

The longer i shoot cast the more convinced I become that lube flinging off the bullet quickly is a good thing. A softer lube is a good thing here.

[beagle]

IMO, based on messing with gyroscopes, bullets do "go to sleep" and stabilize down the flight path. I'm not certain that this is accomplished in a hundred yards but it does happen is my belief. Now, whether this affects the shedding of lube or whether shedding of lube affects this penomonen is the question in my mind./beagle

Bullets going to sleep is certainly believed in by many bench rest shooters and high power competitors.

[beagle]

Then, there's the "shock/bump" when the bullet enters and leaves the sound barrier. This has to have some affect on the stability and also on the lube sloughing as well./beagle

[DrB]

Conservation of momentum says lube flinging from the bullet one direction means the bullet has the opposite resultant vector of the sum of the momentum vectors of the lube bits (it goes the other way). may not be much because the lube bits don't mass much.

Also, you will upset the axis of rotation some because of the conservation of angular momentum... This may damp out downrange depending.

Then you have the shove of gas venting around the bullet with separating lube at crown departure. Anyway you look at it greater uniformity in what the lube does is going to trend to improve accuracy. A very hard coating that stays with the bullet might have as much or more accuracy potential (think gilding metal jacket) as a bullet lube that cleanly flings/ blows off at the muzzle (relatively soft/untacky lube or a good pp load for example).

Uniformity and consistency are keys to accuracy.

See y'all in another month.


Good shooting and best regards,
DrB

[popper]

Not trying to be argumentative, but a bullet responds to forces acting on it, in or out of the bbl. Outside it's wind, air resistance, gravity, lube sluffing, mechanical imbalance, shock wave changes and of course the force vector that pushes it forward. I believe the OP is saying aerodynamic forces can stabilize or damp out and put it to 'sleep'? Shooters evidence on bullet profile vs accuracy tend to disprove that theory, i.e. short vs long, pointy vs flat. A bullet leaving the muzzle with a nose-up attitude may very quickly align itself due aerodynamics, but could just as easily tumble or spiral out of control. I believe the theory behind boat tail designs is to REDUCE aerodynamic effects. It reduces the turbulence and size of the low pressure zone (shock wave) behind the bullet and reduces the deceleration forces. Note the discussions about base deformity and accuracy. Pointy noses 'pin' the shock wave to a stable position, RN and FN don't. A poorly thrown pass doesn't get any better down range, although it MAY appear so. Read a good article 2 yrs ago about spin-drift in cross wind, uphill/down hill shooting which explained these phenomena.

[44man]

Lot of theories and math about cast. WFN will not stabilize, etc but I shoot them to 500 meters from revolvers and clang a ram every shot. I never had a problem because it is a proper boolit hardness, case tension and velocity.
We have so many forces acting on any bullet/boolit it is crazy but only the military has worked it out for each bullet none of which are cast with all kinds of shapes. We are on our own.
To even think of math makes me want to quit shooting so I just do the shooting to see.
Gear maybe does much more then I do and he has never been wrong in all the years we have been here.
You fellas go way out to make sure there is not an air hole in a boolit but you just can not ignore any out of balance even if from lube.
I just had a thought for you to try. Pound a lead shot into one side of a GG and shoot some. Sounds nuts! Be fun to see though.
Remember the Juenke device to check balance of a bullet? I wanted one until I found it will not work on lead.
Anyway, don't leave anything to chance. If you think of something you might be right. Put away the pencil and make some tests.
My idea of a bullet that goes to sleep is that it has reached the perfect spin for the forward velocity. That reduces outside influences better. It is like a gyro with the perfect spin, it resists all motion and tries to correct everything.

[btroj]

Sort of like a top. First start one and they wobble a bit. Once the settle down, or go to sleep, they spin, well, like a top!

Lube that flings off at the muzzle every shot can't influence the bullet later on. Lube that stays on past the muzzle can influence a bullet.

I prefer having the lube gone, no chance it can cause issues later on.

[Alan in Vermont]

I'm not really convinced that ..5 gr. of lube is going to matter one way or the other if only part of it leaves the boolit. Could well be that I never could shoot good enough to detect it, I sure know I can't now. But I'm having fun anyhow. Then again, I'm not prone to making hard to believe claims about my abilities either.

[geargnasher]

I'm not really convinced that ..5 gr. of lube is going to matter one way or the other if only part of it leaves the boolit. Could well be that I never could shoot good enough to detect it, I sure know I can't now. But I'm having fun anyhow. Then again, I'm not prone to making hard to believe claims about my abilities either.

Nobody's trying to convince you, only present the facts as we've found them.

If you don't think half a groove full of lube will affect the way a boolit flys, drill a dimple in the bottom of a lube groove or in the side of a boolit's nose some time and see how they shoot at long range.

Gear

[btroj]

The lube not coming off is a problem.
What if it doesn't at all one shot, does partially at 25 yards another shot, and does entirely at 75 yards on another?

Variations in bullet weight are an issue. Now we are talking about variable variations. What could be worse?

[popper]

I removed ~ .5 - 1 gr from the base band of 175 40SW. 10 rnds formed an arc 2" from POA @ 25 yds. Talk about predictability. Higher rpm exacerbates the problem. Bullet path is not a line, but is ALWAYS a nutating spiral to the target. Trick is to keep the radii of the spiral small.

[btroj]

A handgun at 25 yards is far from ideal for testing the effect of bullet defects. Try an accurate rifle at 100 yards as a minimum.

[Huntducks]

Not for one min. do I feel 2-3>10's of lube will effect accuracy in any maner that you can hold and shoot that well.

Now spin drift will effect accuracy the longer the shot as much as 1" at 300-400 yds right hand twist bullet goes to right. A normal handgun shooting at 100 yds or less might see a slight movement in spin drift.

[Larry Gibson]

I'm not really convinced that ..5 gr. of lube is going to matter one way or the other if only part of it leaves the boolit. Could well be that I never could shoot good enough to detect it, I sure know I can't now. But I'm having fun anyhow. Then again, I'm not prone to making hard to believe claims about my abilities either.

If the lube comes off in chunks and does not come of equally around the circumference of the lube groove then the bullet is unbalanced around the rotational axis. DrB describes the laws of ballistics that make the bullet lose accuracy from such effects and is quite correct. The higher the RPM the greater the effect the imbalance causes and the greater the loss of accuracy. Knowing simply that all precision match shooters, especially long range and bench rest shooters, strive to use the most balanced bullet possible and that includes cast bullet bench rest shooters should give us a good indicaton that throwing lube off unevenly is not good for the balance of the bullet and thus not good for accuracy.

In the 6.5 Swede and .308W at HV threads this subject came up and was discussed at length. I posted pictures of my chronograph screens that had strips of thrown off lube that were not the length of the circumference of the lube grooves. The bullet holes also showed "tails" and lube residue showing the lube was coming off unevenly. Accuracy with such was not good. However, once I went back to a softer lube (Javelina) lube was still evident on the screens but not on the target and accuracy wasmuch improved.

Unless you are using the wrong lube, pushing to high enough RPM to throw the lube off and are conducting extensive enough testing you probably won't notice any difference. If your having fun and enjoying your shooting with cast bullets then all is well on your end. Some of us are prone to enjoy the more essoteric side of the sport though and such interests us. I'll leave the judgement on your shooting abilities to you

Larry Gibson

[runfiverun]

Cast boolits "go to sleep" same as any other boolit. A typical round-nosed, gas-checked .30 caliber is usually quiet by 3-400 yards, then it hits the subsonic transition and all goes to heck again. Most guys aren't shooting them that far for a number of reasons, including expectation levels or loading ability.

I've proven over and over again that lube jettison is critical to fine accuracy by doing accuracy comparisons between slightly modified versions of the same lube. For example, I have a "summer" version of Felix lube, which is simply the original recipe plus a teaspoon carnauba wax. This lube won't group quite as well in several of my rifles in cold weather (below 50 degrees) no matter how hot the barrel because the lube isn't coming off at the muzzle any more. Lube flecks are often visible on 100-yard targets. Deleting the Carnauba and adding a tablespoon of vaseline or ATF completly takes care of the issue, accuracy returns, and the lube flecks disappear. The winter lube starts causing "purge flyers" about every three or four shots predictably in hot weather due to, I believe, the lube being "too slick". Point-blank jettison tests and lube recovery (collecting the spatter off of shiny posterboard and weighing it) usually yield about the same recovery as the summer formula does in warm weather. The guns shoot the same, from first shot through long strings, hot or cold, same exact load and components, with only a tweak to the lube and the observable difference in lube spatter recovery. I've done it enough to pretty much conclude that if the lube isn't leaving the boolit, it spoils accuracy, and that whether the lube does or doesn't all leave at the muzzle is primarily a function of the lube's viscosity.

Gear

using a completly different set of lubes i have the exact same findings.
in fact during the summer i can willingly & predictably blow groups by adding more lube to the boolit or by using the 'wetter' winter fomula.

skim through the "quest" sticky that is still ongoing, you can see and read how lube ingredients affect our shooting,and help follow through on some of the testing.

[geargnasher]

Not for one min. do I feel 2-3>10's of lube will effect accuracy in any maner that you can hold and shoot that well.

Now spin drift will effect accuracy the longer the shot as much as 1" at 300-400 yds right hand twist bullet goes to right. A normal handgun shooting at 100 yds or less might see a slight movement in spin drift.

It happens, whether you believe it or not. Lube that hangs on too long can increase 100-yard, .30 caliber groups by as much as an inch quite predictably. I'm not the best bench shooter in the world, but I can usually hold at least 1MOA at any range with adequate optics and the rifle thrown across a shooting bag, so the effect of partial lube purge is plenty obvious even for me.

Gear

[44man]

Gear, I will be 100% interested in your lube tests.
I am lazy and stick with Felix for my revolvers but YES, I see different group sizes as weather changes. It happens with about any lube.
Right now the .44 is the worst offender with the larger calibers showing very little difference.
I have to think of twist rates along these lines of lube purge. My BFR's all have very fast twist rates while the SBH is 1 in 20".
The BFR 45-70 has 1 in 14", the .475 has 1 in 15" and the JRH has 1 in 15".
Is that why I see less change? Does a slower twist need a more specific lube?
Thinking of twist and going back to when I had the Marlin .44 with the 1 in 38" rate might shed light. Best range was 50 yards no matter but here is a lube test I did. I used hard LBT Blue on the left group and Felix on the right.
Food for thought anyway.

[popper]

A handgun at 25 yards is far from ideal for testing the effect of bullet defects

But it did prove the point. The experiment was done because I was curious about base damage. The way I damaged the base also unbalanced it. If tried @ 100, it wouldn't have hit the target. I posted the target pic a while back. Holes were round (surprised me) and undamaged were @ POA, damaged were in an arc 11-6 oclock around POA. You can do as suggested, drill a hole to remove 0.5,1.0 gr from the lube groove and see what happens. I predict that the further from the CB center of mass the worse the inaccuracy gets.