Here's the deal. A rifle cartridge needs a certain length of barrel to burn most/all of the propellent. When you use a short barrel on a .223, you end up burning a lot of the powder outside the barrel; this is the reason for the extreme muzzle flash/blast. When you put a suppressor on a short barreled .223, your burning all of that powder inside the can, which creates more pressure, more heat, and damage caused by impingement of the burning powder on the expansion chamber and first baffle of the suppressor. Many manufacturers avoid the problems associated with short barrels by using superior alloys, such as Inconel, in the construction of their suppressors. Tac-Ord states that your suppressor is manufactured entirely of 300 series stainless steel; thus the reason for the disclaimer.
Sorry [:(]