I know this deal may not be for everyone...
No BCG, CH, or rear sight. Not chrome-lined. But it does have 1/7 twist, fwd assist, and dust cover...
https://www.armsunlimited.com/Colt-Expanse-M4-16-inch-Upper-Receiver-Assembly-p/ce2000ck.htm
No BCG, CH, or rear sight. Not chrome-lined. But it does have 1/7 twist, fwd assist, and dust cover...
https://www.armsunlimited.com/Colt-Expanse-M4-16-inch-Upper-Receiver-Assembly-p/ce2000ck.htm