I am absolutely delighted about the number of times this post has been read! I hope that everyone who reads it has or will pass it on to everyone they know. I believe it will be critical information in time to come, my belief based on the political postion of this nation.
You can stop worrying about pressure problems anywhere in the gun. Many millions of shotshells have been cut and shot, originally using paper hulls, with roll crimps, then star crimps, then plastic which are the best. If someone out there whould have had a problem, one of you readers would have heard obout it and said so by now. -- Cut shells used to be a legal deer ammo in Michigan, and listed in the game rules as such. Might still be, and even if not specifically banned, legal buckshot can be cut and remain legal. It probably being the most reliable and deadly cut shell one can make, though calling it most deadly would be hard to proove, as deer hit with any fine shot cut shell, through the chest, drop in their tracks every time.
To perhaps relax you a bit more about swage pressure in the choke. Many years ago I cut a 16 guage single barrel down to 18 1/2 inches, for easy carry in an auto.. But I didn't like the open choke bore, so I split the barrel lengthwise with a hacksaw, by hand, and closed the end down to an extra full choke diameter. The seams were gas welded with mild steel rod. The hole was rounded up by hammering the wide part till the bore measured fairly round, then I polished it well, so it looked like a factory choke inside. Now, if any of you are welders you will quickly admit that I weakened the barrel a LOT, compared to factory, and remember I choked it extra full! I shot a LOT of cut shells through that stubby gun and it never changed size up front or anywhere else. In fact, I welded a peep sight on the back of the barrel, and a bead which I filed to shape on the muzzle end. This a necessity because my choke 'leaned' a bit to one side, giving a poi maybe 6 inches off if sighted over the barrel as one would with a factory gun. My, my, what a deadly thing that was, on game, not to the shooter, nor dangerous.
If you don't clearly understand that I thinned the barrel considerably when I polished it up, and softened it dramatically with my welding and mild steel filler rod, ask an experianced welder so you KNOW I was shooting a very much weakened barrel. Now, please, no more fretting posts about pressure problems! Please???