depending on the rifle, WCs will outshoot SMKs. WCs 'act' different than SMKs. Don't ask me why, they just do, in my experience.
IF your SMKs were moving a foot and the RBBTs are moving an inch or two confirms my thinking.
Here's what I suggest: This is major fine tuning and may not be quite right but I am confident it is in the correct direction.
From the chat below and you description of you past tests I suggest the following:
Here's my bases. Sometimes it strings - and sometimes | I'm bettin' there will be an exact powder weight that it will transition between the "-" adn "|" which results in a "." (Bug hole)
I'd suggest 3 test loads of 3 shots each.
Load 1: 71.6 gr
Load 2: 72.8 gr which is right at shot #9 which "shouldn't be way to the left [img]/ubbthreads/images/graemlins/crazy.gif[/img] You may have to do some hunting around in that area of the ladder test as there are a bunch of shots clustered in that horizonal pattern.
Load 3: From the chart it appears as though you are headed to another flat spot as the curve is starting to flatten with shot number 12. Don't know if your running into pressure there or not. IF not I'd load 3 w/73.5 gr.
I'm thinking that after these 9 shots there will be 1 more tweek and your ready to PD w/the 210s.
Also the difference between the highest and lowest velocities you listed aren't enough for a Muley to notice.
Also I'm thinkin' you shot @ 300 yds??
Just my tho'ts. Lets hear how you ended up.