Smith and Wesson AR 10 upper and lower

[Big plat]

I have a 308 win 1/10 5R Smith and Wesson complete upper with carrier group and charging handle. I I am trying to find a lower that will work with this smith and Wesson upper or will this complete upper only work with a smith & Wesson Lower???  Thank you for your help 

[shooterrex]

You posted this in one place already.

Once is enough.