|Formerly shared as "Chesler mystery comic (coverless)", so scans are named 'Chesler-p000' etc)
Later upgraded with fc + bc from HAG
Confirmed as PUNCH COMICS #20.
See rangerhouse's PUNCH 20 (DIFF VER) LINK for an explanation.
A 48-page comic featuring Rocketman, Master Key, and Crime on the Run. It's not an issue of Punch, or the 1946 Atomic reprint issue.
The comic had no cover and is missing the indicia.