I had a few problems myself when I first got into AR's...
AR's are VERY mag & ammo sensitive, PERIOD...
Pop the mags open & check for fatigued springs...
I've been lucky with just giving them a quick stretch to freshen them a bit...
Spring free length should be 1-1/2 - 2 times the length of the mag...
Green mag followers are sometimes a big help...They have an extra long "leg" under them to keep the follower from tilting in the mag...
Check the mag bodies for dents in the sides that could be hanging up the follower...
Get rid of the Black hills hunting ammo, and get ahold of some good "hot" military 5.56 ammo...
Every AR-15 I've owned, gave me trouble with hunting ammo...
.223 hunting brass is too thin, and hunting bullets have extremely thin jackets...
One or the other WILL get wedged in the AR feed ramps and jam...Trust me...
I've had very good success with Winchester Q3131A ammo...
I'm not positive, but I believe this stuff runs at 3100-3300 FPS...
Never chrono'd any 5.56 military ammo, but there is a noticeable difference from one "mil-spec" load to another...
Chances are, with only 100 rounds through this gun, it's not even close to "broken-in" yet...
I'd say 500+ and things will smooth out a little...
1000+ rounds, and it will shoot & cycle smooth as butter...
Best juice for inside the gun is "break-free" CLP...
It comes in a little black & yellow bottle, or a spray can...
Best thing I've ever used...
Your AR will love it...
All my guns are swimming in this stuff...
Very slippery & thin lube/cleaner in one bottle...
Makes cleaning a breeze too...
Another little secret that seems to work for me...
Take the bolt/carrier assy apart, and run the bolt locking lugs under a bench mounted wire wheel...
That helps to "polish" the lugs a little, and helps to "smoothen" lock-up & un-lock in the barrel extension when the bolt closes & opens...
Just remember there are a lot of fresh machined parts in there with sharp edges that 'gotta run close together...
Anyplace you can "de-burr" these edges will only help reliability...
I never had any problems with another AR after learning of these few simple fixes...
As far as "mis-aligned" gas rings, I personally think that's a bunch of crap...
I've NEVER experienced a problem due to the ring gaps being all together...
I can't even begin to count how many times I've pulled a bolt out of a perfectly good running gun, only to find all three ring gaps aligned together...
This is a "gas-ring" myth in my humble opinion...
Hope that helps you guys out a little...