I picked up a Walther KKJ over the holidays. Guess on the serial number it is around 1959 or 1960 vintage. I guess at some point in that history someone wanted to get it closer to the KKM, as the front sight is a globe and there is no rear sight, or even the barrel band. I’m not sure if it was removed, or if the barrel had been swapped for a KKM barrel. There are no marks on the barrel from a previous band (few marks at all...this rifle is in very good condition).

It did come with a Weaver B4 scope. I guess that was the solution to the lack of rear sight. I think I’d like to go ahead and get a peep sight for it. I also freely admit I’m not an expert on the matter. Is there a recommendation here for something different and cost effective? Think indoor ranges mostly, occasional outdoor range, not in competition. I’ve found the Walther basic (https://www.carl-walther.com/products/sporting-arms/accessories/466.72.01.1.html) and sport (https://www.carl-walther.com/products/sporting-arms/accessories/2789281.html). Champions Choice lists the sport for $211 (out of stock). I only know those because Walther sight on Walther rifle, but that’s certainly not a requirement.

Also, any resources on effective small bore shooting with peeps?

What you are look at are entry style match diopters. A mounting base is needes as well.Such a diopter is overkill for a KKJ if it´s used for recrational shooting only.

Check out if there is an 11mm Rail milled into the receiver of your KKJ. If so, you can use it as a mounting platform. 11mm is a standard in the world of small bore and air rifles Lymann is probably a much simpler and cheaper peep sight for this standard as well.

It appears to be the standard 11mm rail. And, you’re right, a $500 match peep is overkill. $211 seemed overkill as well, though 52 euros for the basic Walther peep seemed reasonable. I haven’t found that in the US, though Pyramid Air has some other sights at reasonable pricing for recreational use. Just not really sure what my best option is. Or maybe any of them, at this point, for experimentation sake.