I'm looking at the Swede RB shotguns coming in right now and would love to get one for duck hunting here in north Dakota. My questions are, do these have choked barrels? My model 20's barrels are all heavily choked which is great for sharptails and waterfowl. Second, if I decide to get a gun with a poor bore and line the barrel down to the next gauge do you think it will handle regular target/bird loads if I chamber it to 70mm or will the action stretch? The pressure of the original 12.7x44 round was 11760 psi psi and Max pressure for a modern 12ga shell is 11400 psi so I assume it would be fine I'm only looking at commercial action guns. If lined it would make a great heavy duck gun but not much of an upland gun.