All, SWMBO asked me to straighten up my desk prior to the arrival of dinner guests this PM. In so doing, I came across a few of the targets I fired using the group-buy CB. They were good enough (Maybe "instructive" is a better term.) The rifle is a Win. Mod. 70 "Westerner" (blind mag.), which is glass-bedded, has had the trigger adjusted and wears a 16x Tasco Mag IV 'scope. The latter, I might add, has performed flawlessly for the last 15yrs.. The cases (LC '67, match) were neck-sized in a Lee collet die, expanded with a Lyman M-die, but seated with a 24yr. old Ly. seater die since the seater that came with the collet die has lately been producing a lot of run-out. The 30-150-TL-PB's were'nt weighed, but segregated by cavity: Cavs. 1 & 2 drop almost identical CB's, as do #'s 3 - 6, but the latter four are different enough in weight (than the first two) to merit separating them. I also tried sizing some to .311" and lubing in a normal fashion v. leaving some unsized (.313" - .3135") and TL'ing them in Liquid Alox.
Alloy: Essentially WW's (a thing of the past?) + 1% Sn.
Primers: WLR, as I've had great luck with them and they were (notice the past tense) easy to obtain.
Powders: I've tried both WC 820 and Blue Dot, but prefer the latter for this CB because it burns much more efficiently than 820. I.e., WC 820 does better with heavier CB's and charge weights, which are incompatible with a 140gr. plain-base CB and 14gr. - 15gr. charges.
Results I: The WC 820 loads were dirty, producing OK accuracy, but also high extreme velocity spreads and a leaded bore. I got ~100fps./grain with it, but it won't be near and dear to my heart in the future with the Lee CB.
Results II: Re-examining the newly-found targets (fired @ 50 yds.), I had 9 shots in 1" x 1.25", with 1 flyer to screw things up when using 13.5gr. Blue Dot (~1,530fps, +-23fps) and unsized CB's. A second group of 10 did the same thing except 9 went into 1" x 1" + a flyer.* Those sized to .311" grouped 2X larger than the unsized ones. Another test using ~12.5gr. B. Dot was equally accurate (1,503fps, +-17fps), but with little bore leading.
Conclusion: Since the unsized TL'ed bullets outperformed the sized ones, I'll take the path of less resistance next time and leave them in their natural state. Casting hotter and water-dropping them won't hurt either since they should virtually eliminate bore leading with the plain-based CB's.
*By comparison, my best gas-checked CB's, a RG-4 @ .311" and a tapered (Hanned die) Ly. #311291 @ .3095", body and .302", nose will group (10 shots)into 3/4", sometimes with a flyer, at the same distance.