Several of us on this board have been loading the small pistol primed .45 acp brass for a couple of years now, without any problems. Your theory is incorrect, as our practice has proven. You'll also find that the newer large pistol primed brass from CCI, Federal and Winchester all have larger flash holes, similar in size to what is necessary for the shooting of wax bullets, which I've also done.
This subject has been discussed at length numerous times on this forum.
Hope this helps.
Fred