Reflective designs have real drawbacks, but that is how the REC7 firearm was initially threaded. Compactness in OAL is nice, but residual heat retention in both the can and the barrel end causes rapid deterioration. The design still pops up here and there. In short, avoid it if possible, especially in FA. The threading finally moved out to the end of the barrel (standard birdcage, where it should have been) and now one would want the newer blast can design. Thundertrap 6.8, new XM version is now out.