No issue with TSA when I have done this on several trips the past decade though recently most airlines on USA routes are getting more aggressive about carry-on size restrictions and, in some cases, weight.
I usually fly Southwest Air so no issues there that I have encountered but Alaska and Delta will sometimes have a box template your carry-on is to fit within for you to carry-on. This is done at the gate rather than at the check-in counter. Good news is they usually just make you gate check it at $0 charge but if you have $10,000 of optics in your pack then would be unfortunate to put those items down in the unpressurized, camera-less cargo area.
I flew international on Delta last week and the security check where you place your bag on the moving belt had a restricted opening. My approved carryon barely made it through that opening so not sure what happens if will not fit. I had a plane to catch so I kept moving but made me wonder if this was a new restriction.