Experiments included 0.316" vs. 0.312" diameter in the '06 and WC820 vs. H110 in the 357.
0.312" bottom band   average 1.43"
0.316" bottom band   average 2.3"
Conclusions   The 0.312" bottom band is more accurate than the 0.316" bottom band at this velocity.   Last year I tried a 0.309" bullet and it shot poorly, so 0.312" appears to be optimal.   The purpose of this low-velocity load is to see if low velocity loads behave different than high velocity loads -- and of course, they sometimes do behave differently.
LBT 165 spitzer   average 10.2".   The dispersion was primarily vertical and the wilder shots were high.   This was lubed with LBT blue, painted with liquid alox, and coated with mica.   These were donated by "Bass Ackwards" who has had great success with them.   The barrel was clean, with very little grey wash at the muzzle.   One group was with 0.308" bullets and another group was with a bigger diameter, perhaps 0.309", I couldn't be sure because of the lube and mica.   I only shot the two groups because it was obvious that this bullet wasn't working.   I think it would have worked better if the diameter were at least 0.312".   On the other hand, it performed better than my 0.309" bullets, perhaps because the 14 BHN alloy was obturating to create a good fit in the chamber.
ogival flat point, HTWW, 0.309" with tape on case neck   wouldn't stay on the target.   This was a test to see if last week's poor performance with my 0.309" bullet was related to the sloppy neck fit.   A piece of masking tape around the case neck snugged up the fit considerably.   But it didn't seem to help.   Also, there was a very serious grey wash at the muzzle, worse than normal.
ogival flat point, HTWW, 0.316" bottom band   average 3.53".   Slightly better than the 4.2" average turned in by a 0.312" bullet last week.   The difference is probably not significant.   On the plus side, the barrel seemed cleaner than with the 0.312" bullet, having only a dark grey-black color at the muzzle, compared to a significant grey wash with the 0.312" bullet.
Conclusions   At the very least the 0.316" bottom band did no harm and may have helped a little.   I don't know why this gun likes fat bullets in its high velocity loads.   I thought it might be due to the sloppy chamber neck but if that were the case you would think the taped neck would help.   It didn't.   My gun didn't like the LBT bullets, probably because the diameter was too small.   (previous testing had shown that my gun wasn't keen on LBT lube, either).   I have probably milked the diameter issue for all it is worth, but just to be sure, next time I may try a 0.314" and a 0.3175" bottom band.   Also, I could try making the other body bands 0.316" instead of only the bottom band.   Once the diameter is optimized, I'll move on to seating depth.   Then lube and groove experiments.   And so on ..... one thing at a time.
16.4 gr. WC820   Average 8.1".   The barrel was very clean.
18.0 gr. H110   Average 4.7".   Only one group was fired because this load had already been tested and found to average the same 4.7".   The barrel was very clean.
Conclusions   I was hoping to find an accurate load with WC820 but it looks like I'll have to stick with the more expensive H110 or WW296.