Pete:

I don't think I can buy into this lube purging thing, although I do beleive there is such a thing as too much lubrication. Too much lubrication is more a fault of very deep grease grooves which structurally effect the bullet allowing the bullet bases to slug up differently shot to shot. I have noticed that some combinations of powder, primer and lube cause a fouling condition to occur, this condition is a hard glass like substance in the throat area and will cause erratic muzzle velocities. Cleaning with JB Bore Paste will restore accuracy and consistant MV (with proper load). Recent testing has revealed that minimum lubrication will suffice to velocities over 1600fs (plain base bullets), throat fouling occuring before "leading".

Best Regards,

Pete;
Keep up the good work. I am really interested in this subject. I, specifically, am interested in the details. Discussions like this can prove extremely helpful to a lot of people struggling with various issues.


Dale53

Pete,

Sorry I haven't been on the forum more lately, I,ve been spending as much time as possible doing some ballistic testing while the good weather lasts (no snow).

The comments I made regarding minimum lubrication refer to the actual experience I have had during Jim Bortons tests here. Jim's 3 groove bullet showed no signs of leading and was actually spraying lube particles on my chrono screens 10ft from the muzzle. Jim did encounter fouling (not leading) at higher velocities which resulted in erratic MV's and enlargement of group sizes. As a result of Jim's tests I am of the current opinion that a 2 GG bullet will have a excellent chance of performing well. 

With respect to not filling all the GG's of bullets, while it may prove that lesser amounts will not cause "leading", I'm not sure that it will prove to add to the accuracy of that bullet, in otherwords a bullet made especially made for less lube would be structurally more sound. In the past when I was making bullet moulds, my designs where round bottom grease grooves, .030 wide x .012 deep for 32 cal with 5 GG's, this design is identical to Jim's 5 groove bullet. If I where to make moulds again, I beleive I'd reduce the depth of the GG's even more, to .005 perhaps and 2 or 3 GG's, ideally no grease grooves I think would be best. 8)

The MV's for Jims 32 Miller are very consistant in every way, single digit ES's and SD's., some of the best I've ever seen regardless whether cast bullet or jacketed. His uniformity is equally well at the downrange screens. 

More test work is needed to suggest any conclusive results, so far this year I've noticed some unexpected trends with cast bullets, but until I complete my testing I prefer to remain mute, lest I sound like a total moroon. ??? Its not that I have secrets, just want to make sure of the facts and not create new myths.

Regards,

  Ok! Here's what I came up with on the testing today. Was windy enuf to get the flags standing straight out at times so had to wait for the conditions, so the groups migth not really be indicative of what could have been done.

  Test gun, of course, was the .32/40 Schoyen-Ballard with a 1-16" twist. Bullet was a taper bump swaged Barnett clone weighing 205 grs. with 6 grease grooves. Powder charge was 14.2 grs. of 4227. SPG lube. Rem. 2 1/2 primers. Breech seated 1/32" ahead of the case which engraves the bullet about 1/3rd into the base band. Three alloys were tested..... 1-20, 1-25, & 1-30. Two 5 shot groups were fired with each alloy...... one group with 4 grooves filled with lube, and the other with all grooves filled. All groups measured center to center of widest shots. All shots were chronographed. After each group was fired the gun was cleaned and one fouler shot fired before starting the next group. Here's what I came up with.

1-20 with 4 grooves lubed. Group = 13/16"
MV = 1405.2
SD = 9.4
ES = 25.5

1-20 with all grooves lubed. Group = 5/8"
MV = 1403.2
SD = 5.4
ES = 12.8

1-25 with 4 grooves lubed. Group = 5/8"
MV = 1402.6
SD = 12.8
ES = 30-9

1-25 with all grooves lubed. Group = 3/4"
MV = 1407.9
SD = 5.7
ES = 14.3

1-30 with 4 grooves lubed. Group = 11/16"
MV = 1402.3
SD = 4.7
ES = 12.2

1-30 with  all grooves lubed. Group = 7/8"
MV = 1400.0
SD = 9.4
ES = 23.7

  Since this was a pretty small sample probably nothing conclusive can be taken other than the MV's were fairly steady thru-out the whole test, and the gun seems to like 1-25 best, which has been the case in all previous work.
  Not being a statistician maybe someone else can pull something else out of this. would like to hear about it if you do.

PETE

Dale53,

  If you knew me better, and as my friends will tell you, I'm never satisfied with what I get out of any rifle. Just gets to the point where I get tired of foolin' with it and move on to something else.

  You and the guy I bought the Schoyen from seem to think that what I get with it are ok, and he claims it's as good as he ever got from it. Well, I think it can do better! Thus the other question about "Another Powder".

  I'll agree, and I'm sure we'll hear the same from Brent, that more shots are really needed to gather enuf data to make an analysis meaningful. I think the data I put up pretty well proves that! But, things could be so close in any event that nothing can be proven other than either way would be ok.

  Tomorrow I want to settle the question of whether 1-25 is the best alloy, and then we'll see how it goes. Will you give me a little slack and say another 10 rds. of each would be enuf?? 

PETE

Brent;
I have read and do not disagree...

And it is STILL pretty dern good shootin'

Dale53

This is, indeed, a very interesting & informative thread. The discussion about sample sizes etc is similar to another discussion re set triggers vs accuracy that's happening now on Rick Shay's BPCR forum. Very interesting discussions about testing methods, sample sizes, trends, group sizes etc etc.

I ain't no statistician or even a good mathematician, I quit studying calculus after 5th semester Differential Equations at the State Cow & Chicken School. But I did absorb one or two things about some of it.

First, one group (or one of anything else, for that matter) isn't enough to predict anything. Even three of something isn't really enough data to reliably indicate much other than a (barely) possible trend.

Second, in my mind the trend is the important thing. If a trend can be identified and then quantified, future results can be reliably forecast. Sure, occasional aberrations will appear but then they can be ID'd as aberrations outside of the established trend line, and their relative importance can be better evaluated.

If we have only one or two samples of something, how can we know that these aren't anything more than chance aberrations instead of reliable repeatable data? Answer, we can't! That's why I don't carry around any 'braggin' groups' in my wallet, they don't mean nuthin without knowin' the (Paul Harvey) Rest Of The Story.

Reminds me of a very enthusiastic silhouette shooter of my acquaintance, who has been on the cusp of making Master for some time now but just can't seem to get over the hump. I believe it's because he chases his spotter, IOW he's using too small a sample from which to predict his trend. He will always correct his sighting to compensate for the previous shot, regardless of how it correlates to anything before that. He is assuming (there's that word again) that his previous shot was a perfect cartridge that was fired in a perfect manner under absolutely identical conditions and so naturally if he missed then his sighting needed adjustment.

Well, sometimes that just ain't so. Sometimes a single sample is indeed an aberration, and a second or third sample is needed to show the true direction of the trend. I believe my friend would do better in the long run if he would fire a second or even a third shot with the same sighting before deciding to change, instead of chasing his last shot all over the place. A lotta Highpower shooters have discovered this over the years, but my friend just can't resist anyway.

Same with accuracy testing. To assume a single sample is conclusive or even very indicative is often the grossest folly. Folks end up chasing their tails without ever establishing any sort of reliable repeatable trendable data, and they never are able to figure out what happened except that they KNOW they coulda woulda shoulda done better.

So I think we need to pay attention to Brent when he tells us how many samples we need.