Can a 300 wsm handle 200 grain and 220 grain bullets?
what will be the velocities? I dont have a chrony.Thank you

I'm not really going to answer your question, but I'll venture a guess that when you get to the outer limits of this cartridge, alot will depend on your chamber and how far you can seat a bullet. Every grain will count. If you're stuck with a 2.8" COL, it'll be a different story than if you can squeak closer to 3.1", so even comparing to others' data, you may not get much useable info.
All that said, you should be able to see 2800 and 2650 fps, resp., from a 24" bbl safely. And a 200g 30-cal at 2800 ain't nothing to sneeze at!
I would start with a 60g charge of RL 19 and go up in .5g increments. I wouldn't hesitate to play with 22 or even 25 for the 220g.

www.shortmags.org Has load data from 110 to 220 gr for the 300WSM.

Check out the Hodgdon web site (www.hodgdon.com) as well as Nosler #5 manual, both have data through 220 grain bullets....