Most good athletes in my Army experience were pretty good with the rifle.
Do any of you remember the five event Army PFT of the push up, sit up, mile run (I think), the inverted monkey crawl, and the overhead ladders. The first four I could max, but I never got better than 80% on the overhead ladders and that was on a good day.
Congrats on your Marine, Auditor: that's super. My step dad retired as a Master Gunny fifty years ago this year. Most gentle man, I knew. Some of his friends who served with him at Okinawa and the Chosin Reservoir remember him as a man who never got distracted from the job, ever.