I haven't shot in awhile, but by U.S. Air Force standards I was a marksman with the M16 : )
During basic training I shot fairly well, but missed the scoring part of the target twice. I'm a good enough shooter that on one of the misses I knew I jerked the trigger, the other miss I should have been on target but the bullet didn't cooperate. Basic Training used M16's chambered for .22 long rifle, and NOT the .223, so there is some slop in the barrel for that round and it's not as accurate.
The other 5 times I shot the real .223 version I qualified for Marksman each time.
I did qualify on the .38 snub-nose revolver too, but didn't get marksman with it. Again, I missed marksman by 2 shots...again one was a jerked trigger, the other I should have been dead on but the bullet ended up hitting the dirt in front of the silhouette (bad round, maybe?). For getting Marksman with the .38, one got 12 rounds close, 12 rounds a bit further away, and 12 rounds at medium range. All had to be double action, no cocking the trigger beforehand, and you had to pop up from behind a barrier, fire off 6 rounds, pop down behind the barrier, reload, then pop back up with the other 6 rounds. And you had to be relatively quick, you didn't get a lot of time.
Then you had to place all 36 rounds in the silhouette, and 30 of those rounds had to be within a small circle on the chest, to get your Marksman badge. I placed 30 rounds within the circle, but like I said I missed the silhouette with 2 rounds :(