Re: Load for 300WM Shilen 1:10 barrel ?
Huntstat, what components are available to you? Sometimes that has a lot to do with it. If available, I like the Hodgon powders. I shoot this caliber a lot and have had best accuracy with H-4831SC. I get a little more velocity out of H-1000, but the groups open up just a bit. Still good though. I have also used RE-22 quite a bit in the past, but switched over to Hodgon after reading about the temp stability issues. RE-22 is a good powder though with lots of power.
If you are planning on shoothing/hunting to 600 yds. the 180 bullets will do plenty for you. I shoot the 180 Accubond and have had great success with it. I figure it will work for me to 800 yds. You can also go heavier if needed.
Brass, for me it's Norma. I gave up on the cheaper ones in this caliber long ago. Less consistency in my opinion.
Whatever you go with, make sure you do work up loads and watch for signs of pressure. Every gun is different. Tell us more about your gun.