I also have a Mossberg Maverick 88 with 18.5" barrel.
I added sling studs and an elastic 5 rd. cuff to the butt.
So far it operates perfectly with out any problems.
I'd like to note if you've never shot one of these short barrel wonders LOL your in for the surprise of your Life.
Have'in shot 3" 00 Buck shot in mine I found out quick how loud it was and the flame LMAO !!!! that came out of the barrel was similer to a Mosin Nagant M-44.
Something else that grabbed my attention was the load of Buck Shot travels a pretty good ways instead of spreading fast like I thought it would.
It is truly to me the Ultiment Home Defence weapon and then some LOL.
I carry it just about every where I go now as a back up to my carry pistol.
These Beast will not show any mercy within it's range and if Maverick sold a 20ga. I would much prefer the 20ga, for HD. It is unbelieveable the Fury unleashed by these short barreld shotguns.
One shot would be like being hit by a machine gun...A.H