See, I am going to have to disagree there tahunua001. I will put my Hk against any DI gun for reliability. I promise eight out of ten times you will have to clean yours first. As far as specific pressures, the Hk has a self regulating gas block. It has never failed to fire any round, including low powder sub sonic loads or any hand load I have used. While reliability may be an issue for some piston manufactures or piston conversions, an LWRC or Hk are very reliable, I will even say more so under certain conditions.
ok first of all, you are comparing a $3000+ H&K to a $1000 DPMS project rifle. that's like challenging a turbo'd Jetta to a race when you drive a Lamborgini Diablo.
secondly, I mentioned that Piston ARs do not foul as quickly as DI, so your assertion of being more reliable because I'll have to clean first just goes on to re-enforce my statement. however, give me a cleaning kit and I can keep my AR going just as long as you can keep yours(within reason).