On hunting rifles, without a suppressor, 20 inches is my limit and I wear hearing protection every time I shoot anything. I have a couple of rifles with shorter barrels like a Marlin Marauder in 35 Remington with a barrel a little over 16 inches that I might shoot at the range, but I'll double up on the hearing protection.
To me it's just not worth putting up with the increase in blast and loosing a couple of inches in barrel length just doesn't make the rifle that much more handy.
