I have been using the .200 Swift for over 30 years and consider it to be one of the premier classic varmint rounds. It does have its little quirks, though. You don't want to try to load it to its maximum pressure, unless you are willing to trim a bunch of brass off the neck every shot. The case has a lot of body taper and a gently sloping shoulder - bad combination for case growth at higher pressures.

Load it to the .22-250 level of performance - around 3700 with a 55 grain bullet - case life should be good and accuracy as well. I have used IMR 4064 in conjunction with the Sierra 55 grain Blitzking bullet in the past - great varmint load in my Remington.