GLC, if you can, get the cantilever barrel! My setup caused all kind of problems for me to work out. Back around 1985, when I decided to dedicate the 1100 to slugs, the only rifled barrels available were the Hastings with iron sights. I think they only made two back then, one for the 1100, and one for the 870. With BRI sabots I got one hole groups at 50 yards, so I decided to scope it. Tried the side mounts, where you use the trigger pin holes. I did not like all the flex and movement, so had my gunsmith drill and tap for Weaver mounts. The top of the reciever is a little too thin to thread, so this mount is on the left side, about 45 degrees from vertical. The rings he put on put the scope over the center of the gun. I put a Redfield 2-3/4 Widefield scope on it, and got a couple of groups under 2 inches at 100 yards, one even going just under an inch. But I could never hold zero from one year to the next. I suspected the loose fit of the barrel to the reciever, combined with removing it for cleaning, was causing this. I pounded a copper shim .005 thick in with the barrel, and after a couple of years with no problems, I took the drastic step of epoxying the barrel in, and have had no change in zero in about ten years. Oh and I also swiched the wood stock out for a Bell and Carson composite. And the front sight being visible in the scope bothered me enough to remove it, and have the barrel cut back from 24 to 21 inches. (Thought 20 might be a little short, so went 21 just for something different). Some years ago, Winchester bought out BRI, and those are the slugs I still use. Have made kills from 14 feet, to 125 yards with them. The gun is so light, and the field of view from the scope so big, that I can get on a deer jumped from it's bed about as fast as I do with my SxS on rabbits or grouse. I don't see any need to modernize this thing when it works so well. (and since I have so many $ tied up in it.) :-D