Had a Chance to do an initial tryout of my new Fulton .22lr upper today:
Rifle: Fulton Armory M4A2 upper on a RockRiver Arms lower w/RRA NM 2 stage trigger...2 supplied Mags
Ammo: CCI Minimags,RWS subsonics,Winchester superX powerpoints,Really old remington "valuebrick"
Range conditions:Local indoor range known for its crappy lighting,About 65deg F

Prefiring check turned up a chambering condition where the round wouldn't go into battery all the time,
The feed lips on one of the two mags looked to be a little tight compared to the other but I wanted to fire it first before I bent anything.
Firing confirmed that only one mag was the problem so I opened the feed lips a little and the problem went away..I suspect the the tighter feed lips caused
undo drag...

Testing....
Started out with the RWS subsonic to get a rough zero...Had no FTF,FTE..or any other problems with the RWS...Out of the box the upper shot about 3 1/2" right and 1 1/2" high
I had to move the windage almost all the the way to the left to zero this rifle....Fulton upper use some kind of windage adjustment in the Front sight base and I suspect this was the problem:,
If the Front sight base is adjustable for windage as I think it is I'll rezero once I read up on this some more

After about 75 rounds of RWS I switched to CCI minimags and Winchester SuperX switching between the two every 2nd mag
The CCI's worked without a hitch but the Winchesters had intermittent failure to recock the hammer..I suspect that the winchester's being a little "hotter" caused Bolt bounce when used with the
"light" 2 stage trigger....Someone posted a link for stiffer recoil springs for .22lr uppers and I may give this a try

The Remington "Valuebrick" stuff was of unknown age and I guess I shouldn't have even tried it,But I did....I had Mixed Fail to fire,Fail to eject's,Fail to feeds....Like I said the ammo is of unknown
age and the rounds that messed up sounded "wrong",So much so that I checked the bore several times...Overall I don't count this in the testing...But I used it so I thought I'd tell you.

Overall accuracy:Good....I was shooting offhand @25 yards with iron sights in a dim shooting lane and keeping all shots in a 2-2.5" circle....I suspect that with a scope and bench this
is a sub 1" rifle @50 yards...
Overall cleanliness: Good, People have said these are dirty rifles but from experience shooting about 350 rounds total without cleaning I'd say That my 9mm AR is Far dirtier
....Overall I'm happy and am looking forward to more "testing"....Thanks.........UNDERDOG

In my CIENER conversion I've found CCI minimags to be the best so far. CCI burns cleaner and causes me little to no problems, but it's more expensive. I found the Federal and Winchester to be a close second. I've tried Remmington and won't again. The Remington caused more feeding problems and the powder burns dirtier.

I will try Aguilar subsonic or other subsonics next.

Bump to show off pics..............

Nice job.