The "appear" about the same except the core has the notch near the front. That notch is if you ever want to mount a grenade launcher on it, so not much use to the average target shooter.
They are both 16" chrome lined.
The core says it has a 1/7 twist, but windham says 1/9 twist. So the core will work better if you use heavier bullets. If you only ever shoot 55g FMJ, you won't
notice much difference.
The windham says that model is a heavy barrel.
So
Core = 16" Chome Lined, Standard Profile, 1/7 Twist.
Windham= 16" Chrome lines, Heavy Profile, 1/9 Twist.
So yeah, the Windham is heavier.
Either barrel offers something over the other, so there is a trade off, it's a question of what you want to do with it as to which you will need.