01-26-2017, 06:09 PM
I had to conform it myself. The first Grendel I built was so over gassed it was unshootable. I had to tear it down and measure the entire gas system before I noticed the size of the gas port. I measured it with a drill bit blank at .125 inches(number 30). When I called Black Hole, and was mad as fire, they told me the gas ports on Grendel are oversized to allow for lower chamber pressures, and lower overall gas pressures from the rifle length gas system and the Grendel round. When they changed the gas system, they just assumed that everyone building a SPR would be using an AGB, so they went much larger that the maximum port size for an 5.56. When I ask about wear on the barrel, they said if it starts to open up before 5k rounds they would replace it for free. An Anderson Gas block on the 5th click made the rifle shoot like a dream. Now I use JP's, because they work just a little smother that the cheap ones.