Used ML guns are a bit of a conundrum unless you have the means to examine the bore with a bore scope. Alternatively, a tight patch that rides full length without irregularities. Reason I mention this is that I once had a T/C Renegade in .50 caliber that was quite accurate and reliable. Point being there are good ones out there, just use your noggin when examining them.
If you're a sport give some thought to a flintlock. I have one that fires reliably and is stupid accurate. .45 caliber, 60" twist.
Shorter version, look around, you'll find something.
DD
