There is no reason that 56.3 gr should be giving you compression in an '06... I run 56.5 gr w/ a 165 gr Interlock or SST and don't get near even a bit of compression w/ any of the cases I've tried... Fed, Win, RP...

I wouldn't say that there is an RL that is a "substitute" for IMR-4350, but know firsthand that RL15 & 150s are like PB&J in the '06.

You might want to check your scale... it might be off kilter a bit...