Lube Stars

[S Mac]

I have often read references to lube stars, I think I know the definition, but I haven't really observed them on my muzzle. I have used a small variety of lubes, most recently Ben's red and BLL. my lube is fairly soft, and hardly ever have any leading, so I'm good in that respect. Just curious what others experiences are.

 

[Josh]

This is one star, very dry and carbon-ish, this is from Lamar's Simple Lube. They are much easier to see on stainless steel barrels.

 

[Ben]

Not so hard to figure out that is a 6 groove barrel.

 

[Ben]

 

[S Mac]

So, what's it mean if mine aren't so visible?

 

[Josh]

If your groups are good and you have no leading then nothing, if you are getting leading or off groups you may or may not have too much/little.

Just stiffning or softening your lube can change your star or remove most of it. (I believe Ian and Lamar refer this to the "relax point")

Honestly is is only a tool to use in diagnosing a problem, not a be all end all, the lube star is one of the ways the rifle/load can explain what is going on.

 

[Ben]

If my barrel is lead free and clean at the end of a shooting session and I see a nice lube star on the end of my barrel and my rifle ISN'T shooting tight groups, I usually rule out an adequate amount of lube traveling to the end of the barrel as one of the factors that could be influencing the poor performance down range.

That would send me looking and investigating in the direction of poor bullet design, wrong cast bullet diameter, bad bullet fit in the throat of the barrel , a poor selection of propellant burn rate , wrong cast bullet alloy for the velocity I'm trying to achieve , etc.

My version of Ben's Red is fairly soft and is slung from the bullet upon exit of the barrel. I always have a nice lube star on my barrels , regardless of caliber.

 

[Brad]

A lube star means you have lube on the muzzle. To me it means little more.
I have shot groups with great lube stars that were horrible and great groups with no lube star.
Wet lube stars can mean lbe purging is gonna be an issue. Ever have those days where every so often a shot goes high? Ever notice it happens with a certain regularity? Lube purging is a real thing. If the muzzle is covered n wet, sloppy lube ever think the bore might be also? What happens when that goo builds to a point and then a bullet pushes it out of the bore?

Ever notice some targets have holes with differing amounts of black smear around the holes? Might be different amounts of lube on the bulletater a trip thru the bore? Are holes in the group different this way from the flyers? Hmmm

Personally I look at the target to see how things are doing. If the targets are good then I'm happy. I only look at the bore for leading or the muzzle after I notice the target doesn't look the way I expected.

Damn, I have spent way too much tme discussing this stuff wth Ian and Lamar. I need to get a life.

 

[KHornet]

Now that I have started using Bens Red w/Bll overcoat, will have to pay attention to the muzzle. Not something I usually pay any attention to UNLESS, I start noticing leading.

 

[fiver]

that light graphite lube star Josh shows is exactly what simple lube is supposed to do.
it is low enough in oil content that minor adjustments can be made to give the desired outcome based on barrel length and powder [gas] volume used.

the relax point Josh referred to occurs inside the barrel about 3/4 the way down as the gas volume drops off and the boolit relaxes.
the lube is at a pretty delicate state right there, it isn't being pressed into the barrel and it isn't sitting static so it's changing it's friction property's.
the gas is still trying to work it's way past the boolit although at a lower volume and pressure.
so you still need some flow.
the wet lubes do pretty well here cause they are dumping oil from the case to the muzzle.
the dry wax type lubes really struggle at this point, especially if the temperature is on the low side.
and can leave smears of wax behind which is immediately followed by a lot of antimonial wash.

a balanced lube treated to get just past that point will show minimal lube star and still fling off at the muzzle, but has the tenacity to take higher pressures at the throat.
it's a tunable lube so works well for those that tend to run a variety of rifles with the same basic gas to bore volume at close to the 2-K mark.
but if they chose to go beyond or way below that velocity/pressure window the ability to re-tune the lube is there with small adjustments to the wax or the oil volume.

 

[Josh]

I'm glad 2 of the 3 lube heads chimed in here, I can understand how it works but explaining it (for me) is how I work on cars... I need a bigger hammer... LOL

 

[fiver]

if you think of powder residue as a lube [it's for sure a constituent in a cast boolit lube, and is why I use graphite in a couple of my lubes]
you can get some very similar star's at the muzzle with jacketed bullets too.
stuff like 3031 will usually work it's way down and leave a little poof on the face of the barrel.

 

[Brad]

Photo is a bit blurry but it shows what I mean about the lube ring on the target. Also notice the lube booger next to the hole. This lube left a gooey lube star and was very prone to flyers.

 

[fiver]

all you need to see is the hole off all by itself with the black ring around it.
if you get 4 of them in a string of 20 you got's lube problems.

what really sucks is sometimes those extra 4 holes are only 1/2-3/4" away from the others and you think the 1-1/2" group is good.
when in reality it was gonna be great [like the ones Ben shows]

 

[KHornet]

New term: "Lube Booger", sort of get to ya!

 

[Ian]

A lube star really doesn't mean much. I like to see very little of one, maybe just some oily carbon/graphite marks. The target and bullet holes will tell you if you have a lube problem, then you can use the target and gun condition together to diagnose the problem.

Lube boogers on the paper means the lube didn't go liquid enough or flow well enough in at least one of the bullet's grooves for the temperature, pressure, velocity, and barrel length of the system. The longer the barrel the softer the lube needs to be at the muzzle because muzzle pressure is lower than it is on short barrels. Soften the lube slightly with a non-slippery middle-modifier or plasticizer like Vaseline, white mineral oil, or Dexron II/III ATF to get rid of boogers. Or use less, like only lube the rear groove or just the space in front of the gas check.

It takes very, very little lube to do the job, even at high velocity, but the lube has to be exactly where it needs to be when it needs to be and it needs to be in the correct state to do the job at different points in the barrel. One of the challenges of Extreme Lube was finding something that was fairly insensitive to quantity used, something that didn't accumulate in the bore and didn't stay on the bullet, something that wouldn't change bore friction or oil left behind when going from five grooves filled to just one, that way you didn't have to worry about it, just fill all the grooves in the neck and forget about it. Pretty tall order to get a lube to do that in everything, but part of the key was making a dry lube that was also soft to begin with but had a very high film strength and let go of it's oil slowly. Also, it had to contain slow and fast melting waxes so that it could handle any barrel length without going all liquid like poop through a goose or freeze up on a revolver bullet and not depart when it should. Lots of metal soap and a little bit of paraffin was required for my version to handle all the temps with no cold-starts. It doesn't leave much of a lube star in anything I've ever used it in.

 

[KHornet]

Good thread Ian! Could not agree more.

 

[S Mac]

Thanks for the replies, as I said I see hardly any lube stars and I guess it's a good thing.