Skinner sights has been selling barrel mounted peeps for a while, and XS has peeps for handguns.
I can't really see what the accuracy compromise is with mounting a peep forward, vs an express sight. They both have reduced span over a receiver mounted sight. The difference to me is peeps work near, and Vs work far from the eye.
Ghost rings have become very popular in the last 20 or so years. For me, they don't really function as peeps as the peep function is that the eye self centers because it naturally gravitates to the point where the greatest light transmission occurs. Since by definition the ghost ring is almost invisible, and certainly transmits light every which way, it really requires a different mode of use.
Elmer Keith had a peep on his double rifle, at a time when that was odd, or maybe still is.
After noticing that both Cowboy Action Shooting and PH work favour the express sight, it occurs that there is something specifically excellent about them. One stated reason in CAS is that it makes picking up the target faster than other sights, because it obscures the target the least. Peeps in chassis, often have a lot of stuff in the way of peripheral vision, that may not be ideal when it comes time to acquire the target. What is the reason express sights are used on DG guns? It seems that peeps are the preferred sights on bear guns that use iron sights, here in NA. But for close range work, it doesn't seem there should be a difference between what works best in NA and Africa.
Peeps have been used on Allied battle rifles, while Axis rifles seemed to have barrel mounted open sights. But these weapons have to be able to fire on targets that are either near or at great distances, out to a 1000 yards. So there may not be that much to learn from them.
