Thanks kuduae. I had read your previous post on cocking piece apertures. Based on your post, I purchased a used PH16 to use on my rifle. Fortunately, I was able to use the PH16 "barrel" on my Sportarget. You did a lot of metal modification to make the 16 work on your rifle.
The wood on that George Gibbs 1903 is beautiful! My 1893 Steyr by George Gibbs has a bolt release aperture that looks like a precursor to the Lyman 36.