Gas Port Size for 12" unsupressed barrels?

[LRRPF52]

So I've just gotten a 12" barrel, assembled it today verified the gas block was aligned correctly. Everything looked good...
Took it out for test fire and the BCG would not LRHO. I fired 2 mags with 1 round and they would hang on the magazine but not fully engaging the bolt stop. I fired a mage with 3 rounds and had to hand cycle each one. It would recock the trigger, but not strip the round.

So I'm wondering does anyone know the minimum gas port size to function a CAR length gas system on a 12" barrel?
I was using under power wolf ammo for the test firing.
Don't really wanna say who the manufacturer is yet because don't want to be knocking a good barrel company, but I had the same problem with a 300BO 7.5" made by them. They did great at opening the port up for nothing, but I wanna be sure I'm not talking outta my butt when I start addressing the issue if it is an undersized gas port.

Thanks for any input.
SS33

How did you install your gas block and how did the block fit to the journal on the barrel?

If it was a slip-fit, there might be gas leakage.

A .068" port should run fine with most ammo.

I did notice that 90gr Federal TNT would not cycle fully unsuppressed when using the stiff Maxim Defense short recoil spring that comes with their PDW brace and tiny buffer.

As soon as I attached the ThunderBeast Ultra 5 .30 cal can, it ran like a raped ape, even with the Bootleg adjustable gas bolt carrier turned to the suppressed position IIRC.