I think you are correct. A 5" gu is about tthe limit for comfortable holster carry, especially if your getting in and out of a vehicle. I have some 6 and 6 1/2 inch guns and they are great, but don't go anywhere but tithe range much anymore.

Longer than that is just a pain. I have a 8 3/8 500 and it is asx handy as my carbines. . My XP 100s and Contender the same.