I had a 556 for about a year. It was accurate. I had trouble out of the adjustable gas system my first time out, but after I figured it out, it wasn't a problem. Mine was the optics ready version. I mounted a mini-ACOG on it. It was a really good configuration. The things I didn't like: Weight..... it weighed what seemed like quite a bit more than an AR. Barrel....... not chrome lined. It turns out, none of the Swiss military barrels are chrome lined. I thought the whole world was past the debate about whether a chrome lined barrel was worth it. I guess the Swiss haven't figured it out yet. If I was to get another one.... I would get the classic. The AR buttstock that was on mine was really dumb. The classic folding stock is more useful to me.
For the price of what some people are asking for AK's I built my AR and have about 500 rds without cleaning. Shooting wolf I am going to try just the oil technique and see how long she goes before she starts to jam up etc. I was an AK follower but so far I am liking my AR way better...
Slightly off topic, but polymer Wolf 55 grain runs faultlessly in mine, never had any lacquered rounds to try. Had over 1000 rounds thru it before figuring out ARs run better wet. Knock the big pieces out of the mags, and I don't see an end. So far, just about 500 rounds without a patch down the barrel, or bolt dis-assembly.
