His is a long stroke Type 3. Finding Type 2 piston/tappet gas block for an XCR-L might be a trick even from RobArms. Not sure they even offer that configuration anymore. It's not on the current configurator on the site. You'll need to call RA direct or Nate (navalbeaver above) may be able to help you out if you really want short stroke (Type 2 gas system).