Thanks for the kind words on the rifle.
There are questions on that peep site, I’ll do my best to describe its construction and installation.
That peep sight was a client requested add on after he saw another rifle in my shop with one installed. I saw sites similar to this installed on some rifles at a CLA show a few years ago. I was having trouble with seeing the back site on my own flinter and was looking for new options. I made a copy of what I saw at the show, installed in on my gun and was impressed with the results. I have since made several of these peeps sites and mounted them on a wide variety of muzzleloaders. I have had nothing but good reviews from the owners. Many shooters report being able to double the distance that they feel confident in hitting a target over what they could do with traditional sights.
This peep site is a simple contraption easily made with a mill and lathe, with a little more work, a hack saw, file and hand drill would produce the same product. The peep site body is a 3/4” piece of cold rolled bar stock, 1/4” - 5/16” wide, mounted upon an 8X32 screw shank that is set into, in this case, a 1/4” hunk of cold rolled, that is about 3/4” long, that has been turned down on the lower end to 1/8”, drilled and tapped thru to accept the shank. A collar of brass with friction ridges filed into the sides, acts as a “lock nut” when turned down on the shaft against the collar. An oblong “peep tunnel” is milled in the center of the body of the peep, roughly the shape and size of a large cold capsule. Upon the muzzle side of the peep body, mill a slight channel 1/32” deep and work out with a dovetail file. I use .040 brass for the flange that the peep is in, trim to size and work that like a dovetail on a sight to fit it into the dovetail on the peep site. Leave a few 1/1000’s of the flange standing proud of the surface of the peep body. This flange will slide laterally in that dovetail for your windage adjustments.
A set screw to secure the flange is necessary, A pan head machine screw does the trick. Drill and tap a hole on the top side of the windage flange channel that is close enough that part of the head of the screw catches the upper side of the flange. When tightened, this screw holds fast the windage flange that is slightly thicker than the channel in which it is mounted. A peep hole +/- 1/16” is drilled thru the center of this flange.
The “stalk” is a shank of #8-32 all thread. Turning this shank in or out provides elevation adjustment albeit only in 1/32” increments if that is the pitch thread you use. I have found 1/32” elevation increments for these muzzleloaders to me more than sufficient. Drill and tap a blind 8-32 hole in the bottom of the peep body, screw in the shank, secure it in place with a quick shot of silver solder. Leave the shank long, 1.5” or so, you can always cut it down later.
Installing the site is relatively simply, However, care must be taken to get the mounting base at exactly top dead center upon the wrist and perpendicular to the center of the bore else it will look crooked to the eye of the shooter. The position of the site relative to the shooter is an individual measurement and should be worked out with the person whose rifle the site is being installed. The collar is set into the wood in a hole bored to match the OD of the part a bit of epoxy will secure it in the hole.
On those rifles with a long tang, such as a Mountain Rifle, the mounting collar piece is eliminated and a boss is soldered onto the bottom of the tang at the proper position then the tang and boss are drilled and tapped perpendicular to the bore of the barrel. A couple photos are attached of one of these sites mounted in this fashion.
To dress up the site some add incremental marks on the muzzle side of the windage flange and a center mark upon the body of the peep. These are not MOA reference marks by any means but it gives the user points of reference when sighting the piece in. On really fancy sights I have added a running leaf engraved boarder around the edge of the site body just for fun.
Are these sights truly historically correct? I’m not certain, but others on here will probably know. They are primitive in design that much is certain so they don’t look out of character for the period of these rifles.
The peep sight eliminates the problem many people have with clearly seeing that back sight 14” from their eye. In addition to eliminating the problem of the fuzzy back sight, you increase your sight radius by as much as 15” - that alone makes a big difference. One big problem however, especially for hunters, that peep situation really cuts down on available light. Shots 20 minutes after sunset or in the woods on a cloudy day can be pretty difficult thru a peep site like this. Like everything else in life, its always a compromise.