Charles E
I tend to agree with you respecting the Juenke. Here's what I "think" it does. I think the machine measures the rf energy reflected by the lead core. In so doing, it can predict an out of round bullet (the amount of deflection, i.e., the amount of reflected radiation, will vary if the top of the core is not is not perpendicular and concentric with the steel balls as the bullet rotates) and variations in the length of the bullet by comparing its cross sectional area -- the magnitude of the deflection, i.e., where the needle points on the scale.
The problem, as you suggested, lies in the first application. If during the core seating operation, you get a substantial amount of bleed by, or unequal amounts of bleedby, the total amount of deflection will be horrible even though the bullets may shoot like a house on fire because the amount of lead bleed by is not enough to upset the bullets CG during flight, but it is enough to skew the needle deflection. I actually tested seated cores on the machine and found this to hold true, hence the reason for my hypothesis. This situation is, of course, innocuous. The other aspect, however, is not.
I have a bullet die that makes bannana shaped bullets. One "side" of the o-give is markedly more tapered than the other giving it a sort of bananna shaped appearance. These bullets are wierd. Three or four will go into a tiny hole then one will zing into the next county. They don't shoot consistently well at all. Never did. They all show huge defections on the Juenke and getting the amazingly small multishot mini groups wouldn't be expected.
This got me thinking. Ever notice how the meplats of some bullets are round and flat whereas others are flat on only one side -- the side the extractor punch hits. I did several experiments and found I could create these uneven meplats by either using too small a punch and cocking the jacket / unseated core on the core seating punch or by allowing the edge of the seated core to hang off the punch during the point up operation. Both of these poor bullet making techniques created the dreaded bannana shaped bullets, but to a far lesser degree than my horrible die. The Juenke would detect the difference by showing greater deflection, but in the real world, the only way to distinguish between a bullet with too much bleed by and a cockeyed bullet is to spin them, preferrably at 160,000 rpm or more, towards a target and observe the results.
The absolute reflected energy, ie, there on the dial the pointer points, is indicative, I believe, of the total reflected energy and is an objective indicator that something about the bullet is different, i.e., longer, shorter, fatter, or skinnier. And, unlike the above described scenarios, you don't have to guess whether the difference is or is not innocuous. If they show up on different points on the scale, they will probably show up on different points of the target.
Now you know why I don't make bullets anymore.
