Ill answer in my experience with my keymod
whats the accuracy? depends on ammo. I hit my 12X12" steel gong at 150 yards all day LOL
can it shoot 556? yes
how do you take it apart? stoopid easy, I can take it apart and clean it in 5 min. it is a battle rifle built to strip and fix in the feild. one latch and the upper pivots away and the gas and bolt assembly slides out.
how durable is it? bury it in mud and shoot it. submerge it in water and shoot it. I havent done this but I have seen the videos.
does it take standard ar mags? yes I have had luck with LAR, PCV beowulfs and standard AR mags
hows the trigger, can the trigger be replaced with a better one? no, but the new keymod versions are much much better. same as the new bolt.
are spare parts available for purchase anywhere? wolverine is the main dealer/importer for all XCR products they have it all.
how reliable is this thing? ftf, fte, rounds stuck in chamber? light strikes? Im over 1000 rounds down the pipe with only a few double feeds. not one single FTF or FTE or light strike. the adjustable gas system is great for this!
hope this helps