Wound up with that higher and It is really chrome bore barrel in the future. I think it's an A1E1 from some nomenclature I saw but undecided as I've in no way noticed A different just one. I figured this was produced around the time of product or service advancement https://rafaelxyxut.wikistatement.com/4391165/5_essential_elements_for_colt_m16a1_for_sale