Considering what happened to him, why the hell would Craig lie? You have to believe that he was mentally ill before the Big Event otherwise he wouldn't have turned into a lying conspiracy nutjob and killed himself with a .22 caliber rifle shot to the chest.
That's beside the point. Craig's "7.65 Mauser" story isn't in his 11/22/63 report, not in his FBI 302 and not in his testimony to the WC. In the 67/68 interview with Penn Jones, he said that the 6th floor rifle was a Carcano, but a Mauser was found on the roof. He didn't mention the Mauser in his '69 testimony in the Shaw trial. There is also no mention of "7.65 Mauser" in his 1971 work "When They Kill a President." The earliest I know for sure that he brought up seeing "Mauser 7.65" on the rifle was the "Two Men in Dallas" video, made in 1975. It took 12 years for him to bring it up, despite having plenty of opportunity to do so.
And, it ought to be noted that neither Mary Ferrell nor Harold Weisberg believed him.
And you still haven't told us where the "7.65" came from. No one would have known that was the caliber of a Mauser, except maybe the conspirators. And Craig wasn't the only one. Seymour Weitzman swore an affidavit that it was not only a Mauser, but model 7.65. He later recanted, but he was smart to do so, unlike Craig. Weitzman was in the Air Force and his experience with guns was with Thompson machine guns and pistols, not Mausers. So I ask again, where did he and Craig come up with the 7.65, which they 1st claimed to have read off the barrel?
In the late 1950's and early 60's, Argentina was unloading a lot of their old model 1891 Mausers. Those were chambered in 7.65. The M1889/1891 Mausers are fairly unique for the brand in that they use a single-stack magazine that extends below the forestock like you see on a Carcano. Later Mausers (ie, 1893 and up) use a two-stack magazine that is completely contained within the stock. Someone who had some experience with the Argentine rifles but not too much else could easily look at a Carcano and assume from the magazine that it was a 7.65.
Weitzman spent something close to a year running a chain names Lamont's. Over the years, I've seen Lamont's described as either a regional department store, or a small chain of sporting goods stores. I don't think anyone has ever nailed down exactly what it was, though it has to be the source of Weitzman's "I was in the sporting goods business" comment in his WC testimony. But he only did it for about a year, and was overseeing the sale of a panopoly of sporting goods beyond guns, so he didn't pick up too much experience from the job.