Considering one of two carbines

[grizzman]

Your asks are being a bit schizophrenic.

Lets work backwards...

1 - what is your budget for the upper?
2- what are your must haves?
3- what would be your like to haves?

Based on what you have posted, I think you would be served well with a 16 inch, light weight profile that is free-floated.

I haven’t seen absolute answers to any of these questions.

Is the primary use long-ish range precision (to what degree), or is it close range?

As was already mentioned, if it’s not a dedicated long range rig, having an 18” heavy barrel and PRS stock would be quite inappropriate.

The Colt 6960 upper mentioned above paired with any quality lower would be a good multi-purpose solution. I bought one from Brownells a few years ago on sale and it’s been a solid upper.