If you look carefully, you can find longer scabbards for the longer-barrelled shotguns. They are tough to get in and out the first couple of dozen times, then it starts to shape to your gun and get smoother. If you like the idea, pick one up and try it. You can always sell it if you find it totally unworkable.
“Malo periculosam, libertatem quam quietam servitutem." (I prefer the tumult of liberty to the quiet of servitude.). Thomas Jefferson
"All that is necessary for the triumph of evil is that good men do nothing."
-Edmund Burke, Loosely translated from Thoughts on the Cause of Present Discontents. (1770)