Here are some of my Muzzle break raincovers.
The one on the left is a standard 1"
The second one was sold for the muzzlebreak of a 98 flatline, thats why it has a longer attachment section, but its perfect for going over the Armson muzzle break on my Bushmaster pump.
The third is 7/8
The fourth is for Sheridan brass, it even has a slot cut for the front site.
The fifth is a Taso that was broken so I cut off the ends and slid them over the porting on a Smart Parts All American, wraped some padding and slid the outer shell back on.
The ones on top are spares 1" and 7/8