Hk MP5-40 sear host built by Jayson of Investment Grade Firearms. This was built using a brand new demilled German Hk MP5-40, and a Special Weapons receiver. The original gun was new, it was a crime to have to cut the original receiver up, but the kit of genuine German parts was a real catch. The SW receiver was the final perfected model. I have built several of these guns with Jayson, and they have been in perfect compliance. As this gun was built from a brand new gun, it was my favorite. This gun was tested by Jayson in full-auto before it was finished; it ran perfect and it is in perfect condition.