what .223/5.56 ammo gives the best performance as far as accuracy and velocity out of a 10.3" chrome lined barrel with a 1-7 twist?
Accuracy and Velocity may end up being two mutually exlusive goals with that short of a barrel.
You’ll likely have to find out what ammo your barrel likes best in the accuracy departement. And the only way to get decent velocity out of such a short barrel is with lighter bullets. 
lol, that’s kinda what i figured. i’m thinking about trying some type of 62gr. ammo and see if maybe it will be a happy medium
i shot some 55gr wolf today and the best i could get was 2" groups at 50 yards standing using irons. i’m new to shooting so rag on me too bad:D
The last time markm and I went shooting I was shot my 11.5" with Magpul MBUS’s and used mostly 55gr. ammo. I was able to hit our steel target out to 220 yds. As for groups…could care less really. Minute of perp is generally good enough for me.
Why not try some Black Hills 77gr. Match or Hornady TAP if you really are concerned about group sizes? Probably a better choice of ammo for self defense anyways.
you’re right, i shouldn’t really be concerened with group size. i should just work on consistency with hitting targets out at a distance. what is the opinion on the TAP training ammo?
I haven’t used Hornady TAP training ammo yet only the 75gr. 5.56 TAP.
Velocity is king in a SBR as it will extend the fragmentation range.
So the Hornady T2 and BH’s MK262 are my two personal choices.
C4
who has the best deal on these?
My go to ammo for SBRs:
10.5" - 12.5" guns:
BH Mk262 Mod 1
Hornady TAP 75gr
Prvi 75gr
14.5":
LC M855
Federal Fusion 62gr
My 10.5in has 2 mags of Silver State Armory loaded 70gr. Barnes TSX
and I have SSA loaded 77gr. Sierra OTM in my 16in Middy.
alittle OT but i’m using my friends registered lower until i get the stamp back for mine and was wondering if i need to re-zero the sights when i change the lower over to mine?
they are the exact same lowers. i can’t think of any reason why it would affect anything but i’m still learning so…
Don’t worry about re-zeroing.
There will be no issues.
I hope you don’t have a short barrel upper on his lower because if you do you are in violation of the NFA.
Actually if his name is engraved on the side of the lower and registered to him doesn’t he have to be in possession of it unless he has had it removed from the registry (short barrel mounted to it or not)?
i take the upper off when we leave the range and he is keeping my receiver in his safe until my stamp comes back. i assume this is ok?
that’s kinda what i figured but was one of those" you never know unless you ask" kind of things for me
If his buddy is with him what does it matter if he puts his SB upper on it? Not a permanent change now is it? And yes once registered the lower/SBR needs to be in the “possession” of the registered owner. That doesn’t mean someone else can’t shoot it while at the range.
i probably should have been more clear about it when i said i was using someone elses lower
I read it as borrow, ie take it home.
I’m sure the op is keeping it all legit. I’m just trying to keep him out of jail.
thanks, i appreciate it:) jail=bad