Thank all of you for your replies!
Yes, you can get the 200 gr going pretty easy. In fact, the guy I buy ammo from has a 230 grain hard cast bullet....but he loads them full strength. I buy from Doubletap Ammo at :
They have been very good to deal with....personal service for now...if they grow I know that may change, but for now the service is great. In fact, the owner sent me a new 24# spring free without being asked for my Kimber. He said the 18 # wasn't enough and tossed it in my order for nothing! Now, I appreaciate the freebee, but more importantly I appreciate the thought that I needed more than what the factory supplied!
That's a good point about downloading it to a 40 cal to make it really quiet...but, if it can hold up to the 10MM at full power it oughta' be really well built.