Dan,
Understand about knobs on a Lyman 48, mine came to me with the 1/4 minute clicks, and has had these knobs for at least 30 years.
The stock on my rifle is a modified M1922 (not an NRA Sporter) two stock reinforcing screws, and a recess for the cut-off have been added.
The pistol grip and cap treatment on my rifle is like yours,the grip is left full and tapers down on the bottom to the size of the cap.
My grip cap is horn, oval shaped, tapering on the sides to a flat oval on the top. Center mounting screw.
How does this compare with the cap on your rifle? I am unable to determine this from the photographs.
My receiver is a Springfield Armory M1903, 1921 production.
The barrel is by H.M.Pope.
Thanks, and best regards,
Rick
