Hi, I have just picked up a box of 500 x 350gr SMK for the Cheytac and am looking to develop a load. I have used Retumbo in the past 134 - 135gr, under the Jamison 350gr SMK, Jamison brass, Fed GM215 for about 3145fps. Unfortunately Retumbo powder isn't always available in my area. Just wondering if any one has used viht N170 or Ramshot Magnum with the above bullets and would be prepared to share their data? I am using a Stiller action, Lawton 32" barrel 1:11.5 twist. Thanks.