Here is my HK53k. Now this is always a crowd pleaser. I have an MFI rail which will someday get replaced with a rail welded to the receiver. This is built off a 33 parts kit with RCM CHF barrel. The receiver is a SW receiver. I have a Primary Arms 50000 hour red dot on this host. I like for my red dot to be higher than most and for me it works well. I had Jeff take a old HK stock and weld up the recoil rod and spring to it. The gun is shown with my registered Fleming sear. This is just a great host to shoot with the happy switch turned on. Still have a Vollmer conversion to show along with some other 223 hosts. Then on to the 308 and 7.62x39 hosts.