Ballistically these loads are quite impressive but I don't know that I'm comfortable with your powder charges. Alliants website lists 48.7grs of RL-17 as a max load for a 180gr bullet:

http://www.alliantpowder.com/reload...ight=180&shellid=80&bulletid=189

and gets about the same velocity out of a 22" barrel with a 180gr bullet that you are getting out of a 20.5" barrel.

Using a 20gr heavier bullet with 1.3grs over the max listed load for the lighter bullet almost always means you are shooting at higher than normal pressures. I see where you say that you aren't getting pressure signs but you ARE - VELOCITY IS A PRESSURE SIGN! If you are getting the same velocity with heavier bullet and heavier powder charges in a shorter barrel no less YOU ARE USING HIGHER PRESSURES! Your rifle is probably a very finely fitted gun that won't show pressure signs on cases as a less well blueprinted one might.

I wouldn't use your powder charges with that weight bullet!..................................DJ

Remember this is all supposed to be for fun.......................