Update; After some more measuring and slugging each cylinder, as best as i can measure without a micrometer all cylinders seem to measure at .4520. From what i have read the newer rugers are more consistent in there cylinders, and mine was manufactured in 2012. I have found a very good shooting load with 9.2 gr. of W231 and the missouri 255 gr. SWC with an 18 BHN. This gives me an average 1033 fps with an extreme spread of 30 and average deviation of 10. This is the most consistent and accurate load i have found so far. It is a nice target load and i'm sure it will put down a pa. whitetail! It shoots a nice cluster at 25 yds., now i have to practice my offhand shooting. I did purchace a lee .452 sizer to run my bullets through, then lube with lee liquid alox. Hope to eliminate the little leading i was getting. Have 50 rounds loaded up and ready to do some shooting. Have some 250 gr. xtp's loaded up a little faster ,but i really wanted to shoot lead with this gun. Thanks for everyones advice!!