im happy that i have choosen the piston system, i've seen sometimes that di rifles have malfunction from the dirt in the system. two times ive seen a guy shooting an di rifle, first time (with an oberland arms) after finishing a stage the ro says "open action" but the guy couldnt open, the last round was stuck in chamber, after firing this round in the dirt with the ro's permission he could finish "show clear" command, now starts the cleaning process, open the gun, using chamber brush -> cleaning! this was in 2009.
last year a different shooter, the same problem with a sabre defence rifle in my squad.
this kind of malfunction i dont know from my piston rifle because it runs clean!
A failure to extract is common in the AR platform, when people fail to clean the chamber or when their extractor spring goes out. I have seen a few broken extractors, but not something I have seen a lot of. The most common reason for a failure to extract is bad ammo (i.e. steel case lacier coated, bent or dented). I have never seen an AR (GP or DI) fail to extract due to carbon fouling, but that’s not to say it never happens.
the only malfunction caused by the rifle was, after i added a ebrv2 extended bolt catch, the bolt carrier stays not back in the open looking position after the last round, the hole for the pin was 4/10 mm away from where the original h&k bolt catch was. i removed the ebrv2 and attached the magpul bad lever over the original h&k bolt catch and it works fine again.
do you think the groups are to bad or to good for more than 5000shots? im not good in shooting bondaged to a table, when im in a store in future i buy a box of good (62grn or more) ammo and try it.
I think those are excellent groups, but I have to admit I tend to doubts. I have worked with the AR platform for roughly 15 years and have yet to see that type of accuracy at that high of a round count without a match grade barrel or the use of match grade ammo. Hints my questions about the ammo and barrel. I do not doubt you or your word, just trying to get all the data behind what you’re doing to achieve that grouping. Personally I think you have one hell of a set up and if I were you I would not change a thing until accuracy changes.
i think the h&k 416 (not available here in germany!) has a chrome lined barrel, the civilian mr223 not. but the first series have a big space between chamber and first twist, some think that causes poor precision. the first pictures i've seen 2008 are made by the gun seller "waffen centrale" he gets 5 shoots in a Ø19mm paster using a g3 flash hider and a 3-12x scope at 100meters. you can find the pics in the german forum "waffen online" search for mr223, its the largest german gun forum.
here in germany is a gun smith who has build a new piston system. the piston is direct in front on the upper reciver and gets the gas from a normal gas tube. i've seen the rifles on the IWA this year, but the guy is crazy, they want to sell this rifles for 3000€ or more, the most expensive ar i ever heard of. and there has been no bullet through the barrel till now, some here think this piston system wont work propper.
heres the webside -> http://www.dar-germany.com/
you can join the "dar event" and shoot this new rifle, if it works till then.