I hadn't even thought about it.. I'll ask him next time when we chat.. Very good point.. Thank youI'll say this: To him they may seem to be and therefore are the same.
For example, many years ago I was running a firearms training course. The purpose of one particular session was weapons familiarity with a number of different handguns. The pistols included a Browning pistol, (L9A1), a Glock, Walther, and a Colt 1911A1 as well as a number of others ranging in calibre from .32APC and 9mm to .45ACP. Each student had an opportunity to handle and shoot each of the pistols. During the debrief, they were asked what they thought of each handgun. Interestingly many of them felt that the larger calibre .45 Colt with greater recoil was easier and more comfortable to shoot than the .32 Walther.
The point is it was a matter of personal perception based upon a unique 'feel' each person has. I wonder if this -- this 'feel' -- is what your father means.