Peep sight.

[user 48679]

While not the best location for a peep sight (nearer to the eye is better), here's a Skinner barrel dovetail mounted peep sight:

http://www.skinnersights.com/barrel_mount_6.html

Marbles also makes barrel dovetail mounted peep sights:

 

[Winchester97]

While not the best location for a peep sight (nearer to the eye is better), here's a Skinner barrel dovetail mounted peep sight:

http://www.skinnersights.com/barrel_mount_6.html

Marbles also makes barrel dovetail mounted peep sights:

I have one of the skinner barrel mounts as well as a few williams barrel mounts. I have found they work great with a larger aperture installed, or as a ghost ring with the aperture removed for hunting. I was skeptical being that far away from your eye, but no worries here.

 

[Nameless Hunter]

I have on of the Marbles on my GPR. Not bad for what it is. Did a modification. Now like it better.

https://www.muzzleloadingforum.com/threads/marbles-bullseye-modification.125873/post-1739690

 

[Eric Krewson]

Well, I have been building guns for a while, drilling and taping holes ain't a big deal for me.

As you can see from my picture I didn't make a sight to be the exact width of my tang and everything looks a little sloppy, I don't like sloppy. Before I drill another hole in my tang I will have to make a sight that looks like it grew out of the tang.

I just got a new hip, things haven't gone as well as I had hoped (I am 6 weeks out from surgery). Standing in my shop for anything over an hour gets uncomfortable. The sight in the picture may get a drop of JB weld under it.

 

[Nameless Hunter]

Well, I have been building guns for a while, drilling and taping holes ain't a big deal for me.

As you can see from my picture I didn't make a sight to be the exact width of my tang and everything looks a little sloppy, I don't like sloppy. Before I drill another hole in my tang I will have to make a sight that looks like it grew out of the tang.

I just got a new hip, things haven't gone as well as I had hoped (I am 6 weeks out from surgery). Standing in my shop for anything over an hour gets uncomfortable. The sight in the picture may get a drop of JB weld under it.

Best wishes on the new hip getting better!
My mother-in-law had both knees done at 88 and 89, but I'm guessing a hip requires a bit more recovery effort.
I have the same "perfectionist" affliction - it has caused my many extra hours, 'cause "good enough" sometimes isn't good enough...