You might think about leaving the thumbhole buttstock on there and adding a couple of inches to the barrel. BATF regs specify the attachment mustbe, as a minimum,spot welded or silver soldered in place to qualify as "permanently attached". Red loctite doesn't meet their definition. Could be something as simple as apiece of steel tubing with an inside diameter the same as the outside diamter of the barrel's muzzle. These guns are a real handful with just the pistol grip.