That surprises me.... that the groups would open up from 1.5" to 5" going from 100 to 148 grains. I would have guessed the gun would burn 130 grains and dump the other +/- 20 and the groups might go to 3" or so.

What is your barrel length, twist and is it scoped?

I'm planning to adjust my sights for the 200SW and shoot the 200 XTP's for most range work this summer so I'm very interested in what your results are.