Would this be with a pistol grip as well? Because that would be illegal unless the stock was fixed.
This 1100 was built in the 70's so it is pre ban, a pistol grip is just fine.
Now that i have torn down and have a better understanding on the anatomy of the 1100 i see that without serious modifications the AR srock will not work. They are not overly clear on the websites for the grip adaptor pertaining to the 1100. They will fit an 870 just fine, if you can find them but without relocating the recoil spring assembly that is in the stock it simply wont work. I read a decent amount of information on the mod and it was never made overly clear that without serious modification it cant be done, and since no one offers to relocate the recoil spring anymore its kind of a lost cause for the 1100. From what i read about the company that did it, they didnt do many and the work was pretty shoddy.
In searching i actually came across a link to this thread many times. I wanted to add this info here to hopefully help anyone in future and save them some trouble. I spent a good many hours looking into this mod and it is just not something that can be done easily.