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Let's try using a bit of logic.
An 1100 uses a mature and reliable design that has many parts little changed even from the predecessors that also had some versions available as magnums.
If you have a standard frame with a 2-3/4" barrel using the standard 2 holes in the gas cylinder and shoot high brass heavy loads through that barrel, nobody is going to say that shooter is abusive to the gun. Sure, there are less abusive situations if we look at just the impact inside the gun, but guns are meant to be used, and used with the most effective load deemed necessary. If that happens to be a modern heavy turkey load (such as 1-5/8 oz. at 1250 fps), that is still within the designed parameters. All that pressure is being applied to the mechanism through 2 gas holes.
Now look at that same frame with only one change: a 3" barrel of any type, steel shot or whatever, just as long as it has one gas hole. What is a heavy turkey load for 3"? About 1-3/4 oz. at 1300 fps, and all of that pressure hits the mechanism through ONE hole. How in any way, shape, or form, can that be considered abusive to a non-magnum 1100 frame assembly, if the other situation is not considered abuse? There is absolutely no strength difference to the frame or internal parts, and the barrels are of identical construction, save the chamber length and a gas hole. The action bar (inertia) sleeve is heavier for the magnum, but that is not because it is needed to reduce abuse to the magnum frame: it is there to increase the action reliability when using lighter high-brass loads (2-3/4" varieties), since one hole of gas bleed needs more mass to keep the parts moving against the action spring for the full stroke. The gas only has a small amount of the total stroke length to apply pressure and get the parts in motion, so more inertia can aid reliability.
Logic prevails: any other conclusion doesn't match reality.
Don't take anything I say as encouraging any shooter to go against any manufacturer recommendations, but I have already gotten assurances that I have the correct answer here and now.
kirbythegunsmith