I'm asking for some help to figure out why my new build is short stroking.  Here is a quick list of the parts involved.

Tubb flat wire buffer spring
H1 buffer
Full auto bolt carrier
JP Rifle Bolt
JP Rifle 18" barrel
JP Rifle low profile adjustable gas block
JP Rifle rifle length gas tube

The gas block is most definitely aligned to the gas port.  I've aligned it twice.

Shooting American Eagle 55gr FMJ

I started with the gas block adjustment screw backed out 1/2 turn.  At 4 turns out, the .223 brass finally ejects.  At 7 turns out, I still can't get the bolt to lock back after the final round.  Any more turns out and the adjustment screw will fall out.

Can anyone with an adjustable gas block tell me around how many turns out it should take to make the bolt lock back?
Is it possible the combination of the full auto carrier and H1 buffer are too heavy?  I can't imagine it would be but I'm grasping for ideas at this point.

Any thoughts?

Check and make sure your gas key is not loose.

Does the bolt lock back on an empty magazine when you pull back the charging handle ?

Also do you have a regular milspec spring that you can try out ? Tubb springs are stiffer, and you're using a rifle length gas system on an 18 inch barrel.

Keep us informed of your progress.

The gas key is staked and solid.

The bolt will lock back with a mag in by pulling the charging handle back.

I do not have a milspec spring handy.  I was thinking of picking one up along with a 3oz buffer and swapping them out to see if that lightened it up enough to cycle properly.

Good gas rings?

They're brand new so I would assume they're good.

Can you stand the BCG up without it falling?

You'll need to replace the gas rings.