I just got my form 1 approved to convert my auto ordnance Thompson to SBR. Got a gunsmith lined up to change the barrel. Problem is, auto ordnance/kahr is sold out of factory 10.5 inch barrels. And due to shut down in Massachusetts, there will not be any available for the forseeable future. My question is, has anyone ever done a conversion like this with an aftermarket barrel? There are numerous of these options available. But most say, mil spec. And this is a closed bolt semi auto. Im just not 100% sure the barrel fits on both it and the open bolt full auto the same way?