I would like to hear from someone who has shot a 1911 in .40 and .45. Or someone who has shot a Glock in .40 and .45. That would be a much fairer comparison. Same weight, same bore axis, same everything but the caliber.
Easy enough. Scroll up.
As I said, I have P250 conversion kits (full size) in .40 and .45.* When firing them back to back (180gr .40, 230gr .45), the 45 does indeed kick more. The .40 isn't quite as snappy as I expected, but it is a touch less of a push than the .45 (although it's recoil characteristics are definitely closer to .45 than to 9mm and .357sig).
*The P250 full size kit is the exact same size across platforms... the only difference on the grip frame is a larger/wider cutout for the .45 magazine. The trigger module used was the exact same one (not same model, same exact module, so the trigger pull was identical). Sig reports the same weight for all calibers (29.4oz, with mag but unloaded). It's as close as you're going to get for being able to duplicate everything about the gun but the caliber.