Lube Purging

I'm the Tom Gray who discovered that too much lube will cause fliers.  And, for lack of a better term, called it "lube purging".  This was quite a few years ago when I was shooting the CBA benchrest matches.  You can argue the cause all day long as we really don't know for sure what's happening inside the barrel when a lead bullet with lube is fired. But, the effect of too much lube can be seen and it's for real. 

The way I found it was when I was shooting a loverin style bullet with lots of lube grooves. I had a very accurate benchrest rifle where you could see some of the more subtle effects when changing different things with the load.  With too many  of the grooves filled with lube there would be a quite predictable unexplained flier in just about every 10 shot group. 

Just for the heck of it I tried reducing the amount of lube on the bullets by wiping out the lube from the lube grooves and eventually with just a couple of grooves filled, the fliers went away. Figuring that I was getting too much lube in the barrel I repeated the test several times and with different guns,bullets and different types of lube and the results were the same.  

It turned out that there was an optimum amount of lube on each particular bullet design to eliminate these unexplained fliers. This was a simple thing to test if you had lots of lube grooves and could get more than you needed on a bullet. It's something that is easy to do. Just take your particular bullet and start reducing the amount of lube and see what happens. If you go too far, you may get leading. Clean the gun and start over if that happens. To see how the barrel is doing, look into the muzzle end of the barrel and see if there is any light flash of what I called streak  leading near the end of the barrel.on top of the lands.  If there is, the bullet probably ran out of lube before it ran out of barrel. So you have found what is too little lube for that barrel/load combination. I found that about .4 grains ( that's 4/10ths of a grain of  lube by weight,)  worked best in my benchrest rife with a tapered throat and a identically tapered bullet that fit the throat with a slight interferance fit. If a person has a sloppy bullet fit they may never see the difference as there is so much blow by on the bullet before it seals in the bore that they blow the lube off the bullet before it goes down the barrel. If that's the case, you won't see the lube fliers in the big groups that will result.  

You can argue cause and effect of fliers and they can occur for a lot of reasons. You will find folks who do tests that won't show the subtle effects of too much lube. If their rifles and bullets don't have the accuracy potential to really see the cause and effect they well poo poo the theory as they can't see it in their groups. In other words, it the bullets are bad and the barrel is bad and the bedding is bad or other things like poor bullet to throat fit are causing a lot of fliers it's too hard to see a subtle thing like a flier caused by too much lube. I.O.W. you have to have a test bed that has the accuracy potential to see the difference that the amount  of lube makes to the groups. If the gun shoots all over the place, the shooter won't see the fliers that are in the groups caused but too much lube. 

In summary, If you have a bullet that has a lot of lube grooves, you probably don't have to fill them all up. I've found that you can have too much lube on bullets and it will cause fliers. I first did these tests and got the lube fliers using the old NRA alox formula. Different lubes have different effects as far as causing fliers. During my lube testing I found that lubes that had parafin wax as a base caused more lube purging than formulas that had other types of waxes. The type of wax makes a big difference.  

Your mileage may vary. 

Tom