Here's a tip for all those NSF guys who are planning to get marksmanship for their ATP. Its old news already, but I'd wanna stress this out: Take your heaviest lens and aim at one point for 10 mins every day. For me I attached my 500mm f4L to my camera and aimed at one point for that amount of time. In the end at the range, ATP was so easy. Scored 100% for my ATP! With M16, not SAR21 some more! Easy money too.
Hope this helps!