Mike,

as promised, here's the data for your 45 gr. bullets in my .20BR.

Barrel is a Douglas, 12T, 26"
Bullets were seated to engage the lands firmly ("square marks")
Primers are 205GM's
Group sizes are average of three, five-shot groups
Velocity is average of 15 shots, at 22*F (cold!)

N540      31.7 gr.  .415 avg.   3917 fps
N550      32.7 gr.  .590 avg.   3816 fps
Big Game  33.2 gr.  .430 avg.   3737 fps

I'd expect all of these to run a bit faster at higher temperatures.
None of them are hot loads at 22*, so I think they will "probably be okay"
when it warms up.  But I'd advise anyone to approach with caution, as always.

Looks like the load with N540 is definitely the one I'm going to try on
coyotes.  HOPING to make it out next Saturday.  Will let you know how it
goes as soon as I'm able to put one into old Wiley!

Thanks!

- Dave