Replacement regulated ASA HEAT CORE Body for Milsig M17 Important Notice:This is an regulated HEAT CORE body set up to 20 joules. It does includes complete regulator and Pressure Release Valve . It is what M17G3 and M17A2 come with. It is used together with a softer main bolt spring and lower input pressure (under 20 joules) to maintain a balanced system. Failure to do so may result in improper cycling or malfunction of the full-auto mode. For set up over 20 joules stiffer main bolt spring and sear springs are required. it is also nessessary to readjust Pressure Release Valve Compatibility:With proper springs, technically compatible with the following models: M17 G3 T17 M17 A2 / M17 A2 PMC M5 Magnus M17 CQC / PMC M17 ELITE M17 SMG M17 XDC M17 DMR MK3 / Paradigm Pro Not Compatible With: Older blowback models including K-Series MK1/2 and Paradigm 1