Professionals for a Massacre is a 1967 spaghetti western starring George Hilton, who did quite a few of these types of films. Edd Byrnes, who was in the 77 Sunset Strip TV series and in Grease also stars. I enjoy Spaghetti Westerns, and this is one. There's nothing here to set it above the rest, but it's a fine enough entry in the field.
Reviews? I can't find them. Anywhere. Rotten Tomatoes doesn't even have a listing for it.