So I just put together my latest, no issues in assembling. I have a situation that I have not encountered yet though.

If I draw the CH rearward and release, the bolt locks up into battery . But if I ride the handle forward,  then I have to physically lock the handle and seat the bcg using the FA.None of my other builds share this characteristic.

The gas tube appears centered and I see no markings on it from impact. I have not lubed everything yet and am wondering if that is my issue.  Any insight?

Specs: all new parts
F/K surplus A2 upper
14.5" Colt SOCOM bbl
PSA premium bcg
standard CH
standard SS carbine gas tube
standard GI bbl nut/delta
RAS M4(not that it matters?)

Lube bolt and carrier, cycle it 10x, and it should be fine.

Ill get after it here in a bit. My thinking as well. Just wanted a 2nd

ALL new parts?     Break in.      Had a new ARP nitride barrel and new nitride bcg hanging up for first 15 rounds.     Fired ok, would not cycle.   Brass was siezed in the chamber.

Had to put pressure on CH and bump butt stock for first 10 rounds..........then it got smoother.   After 15 rounds no problems.    Lube helps but new parts need a break in.

Yes, all parts are new.

Never ran across this with my other builds. This is new to me so I figured I would ask. Others were smooth as silk. Figured, better not ram it around until I got a few opinions. Thanks.

There's nothing wrong with what you have.  Don't need to do anything.  If it's problematic when shooting, then start worrying.  

Most of mine won't drop fully into battery if I ease the bolt forward, but I've not had any problems with any of them.

So lube seems to have helped some. Still, not like my others. Riding the handle causes the  bcg to stop just short of battery.
FA to seat it, not gritty at all.

Im gonna soak the bcg in some Mobil 1 overnight and run some rounds through it tomorrow.
Unless our ice storm here is what they say it will be

I am guessing new parts/tolerances is the "issue".

Thanks for the input.

If this is happening when chambering a round it is just break in.
If this is without ammo then you may have a problem.
I would look to see what was rubbing and make sure the BE is clocked right.

So, I have to withdraw my previous comment.  Mine all close without issue when I ride the bolt forward.  However, they're not new.  

If you drop the bolt on a cartridge, does it drop into battery?  If it doesn't, you obviously have something to look at.  But, if it does, just get to the range and shoot it, and then worry later.

BE timing appears correct. Markings from contact/engagement are uniform on BE and bolt lugs.

Bcg locks into battery with a round. I have messed with it a bit, seems a little better. Im going to try a couple of other bcgs, see what happens.

Another cleaning and heavy lube too.

Update: it's the bolt/bcg.
Tried 3 others, zero issues. This one does it in all my others.

It's better with lube, and seems to be working in.Im gonna give it a few more reps to break it in and shoot it. I'm calling it new parts syndrome for now.

Thanks to everyone for weighing in.