You can try to hide it behind the frizzen spring but it's still visible. A little off center - no big deal, within reason. As demonstrated in the drawing, it's a sore thumb, no way to see it otherwise. That's far too off center. If you want your rifle to look like an old rifle, it needs to be relatively centered - a good majority of locks were purchased locks, and the holes in a casehardened lock plate would surely have been drilled first. Most original rammers or even old replacement rammers taper down to the 5/16" max range, quite a few even smaller @ 1/4" at the inner iron tapered tip, so I don't see any issue with edging into a full 3/8" rammer hole. With a really nice rifle - meaning a really appealing piece, good architecture - everything in the lock/breech/rammer area is a juggle, especially with some of the later Lehigh and Bucks pieces. There are one heck of a lot of antiques that evidence lock bolts edging into both the rammer hole (lots of notched lock bolts) as well as notching the barrel. Many lehighs with ramrod holes practically running right into the barrel channel at the breech. There sure is going to be some juggling there.