Philadelphia Ordnance can supply an ATF approved blank firing 10 1/2" barrel for your semi-auto Thompson. This barrel will make your Thompson look correct - like an original military Thompson - but there is no Short Barreled Rifle (SBR) paperwork or tax required. When this blank firing only barrel is fittted to your gun it is still a firearm, but it is not considered to be an SBR.
The Phila Ord barrel is precision machined from 4140 steel and has front muzzle blast - not sideblast. The blank adaptors can be removed and the bores checked and cleaned thru to the chamber. To fit the Phila Ord barrel you remove the old barrel and screw on the Phila Ord barrel as you would with normal barrel change.
The Phila Ord barrel is suppled with three adaptors, wrench, instructions, and copy of ATF letter stating that the barrel is legal (non-SBR) when fitted to your rifle.
We have adaptors available for the popular blanks.
NOTE: The bore of a compensator is smaller (0.465") than the 1/2" (.50 cal.) diameter of the adaptors.Therefore when setting up for blanks you can either a) not pin the compensator to the barrel and screw the comp on and off as needed, or b) bore the compensator to 1/2" before pinning it to the barrel.
The compensators on current production M1927A1 semi-autos are pressed on to the barrel. They cannot be unscrewed and fitted to the blank barrel. Older semi-autos do have threaded compensators. The Phila Ord barrel has the correct thread for original military compensators and new production compensators that have the correct thread. The compensator assembly consists of three parts - the compensator, the front sight, and the pin which pins the sight to the compensator and the compensator to the barrel.