Similar from tacticatalhttp://www.shotgunworld.com/b ... p?t=124070
Sounds like youve got the bases covered bro.
Have at it. Post us a pic... everybody likes a pic.

 

As said before you look pretty set up for the extention. You mentioned wanting to use the old style cap. I guess you mean if you take off the extention. If so, you need to get one of the friction spring retainers instead of the plastic one that worked with the dimples. This will work, but you will have to check to make sure the cap stays tight because you would not have the little spint and ball like thing on the barrel ring that the older models had that worked with the old style cap. Any gunsmith could add that to your express bareel if you wanted it. The gun will work without the magazine spring retainer, but you have to push the spring down and screw on the cap at the same time. If hunting where a plug is needed, some wardens take a dim view of the plug coming in and out with just taking off the cap.

 

Were you get the factory extention and clamp from?