paducahrider; normally 99% of the time, I would agree with every word you just said-- that being said, we are talking about the 243 here. And just as there are ballistic anomalies that go on with the 22lr round, that happen with absolutely no other bullet, and that goes for other 22 cal bullets as well, there is a few strange things that happen with the 243/6mm bullets. I am not sure what it is, or even how to correctly describe what is happening, but for some reason, you will find a lot, A WHOLE LOT, of 243 shooters, with very good rifles, with 1/10 twist or faster, who when shooting light bullets all the way up to 80 grains, they group ... very .... mmeh, to say the least, then start throwing in anything from 85's up to 105's, which you would think is too heavy at the upper end, and suddenly they are a one hole punch.
If I were to take a stupid guess at this, I would say that the lands/grooves aren't being made correctly, for a 6mm bullet, that is traveling over 3000 fps from a bbl, and because of this and the molten action of a bullet during it's internal flight, there is a certain amount of slippage, or on and off traction, that the bullet is getting from the bbl. And that speed and grip inside the bbl, is not consistent because of this, so the lighter bullets get ' thrown around' a bit as they go down the tube, at differing speeds, causing weird accuracy or groupings downrange.
Then again, I may not have a clue to what i am talking about, and am just
totally full of it...