Lines of Effort
Effort QuietAir is a 4.5mm air rifle suppressor that might not be able to be built legally in the United States without payment of a $200 tax. Thus, we catalog it here for Americans visiting overseas, or folks who live in jurisdictions which don't have legal difficulties with making air rifles even quieter. It may serve as a starting point for a .17" HM2 suppressor design, perhaps with water-cooling to keep the ABS baffles from melting, and possibly with CO2 injection to prevent first round pop. Interestingly, it may serve as a catalog of illegal plastic brick constructions in the United States.
Plastic brick holes typically are of 4.9mm diameter, which will easily accomodate the common 4.5mm pellet or BB (.177" caliber in the United States). The design above, which we enclose the MLCAD file for, is a simplistic suppressor design, which does not incorporate modern baffle techniques. However, such a construction of plastic bricks in the United States may constitute a felony under the National Firearms Act, so Americans should seek an opinion from BATFE's Technical Branch before actually assembling any plastic bricks to designs shown here.
A recent conversation with a BATFE agent at a Texas gun show confirmed the difficulties of producing such an airgun suppressor in the United States, and the agent suggested we write the Tech Branch for an opinion, which we intend to do, after receiving input from the plastic brick, airgun, and firearms communities.