>>541
https://www.colt.com/detail-page/enh-patrol-rif-556mm-16-301
EPRライフル単体の説明にはM-LOK Capable Handguardとありますが
https://www.brownells.com/rifle-parts/receiver-parts/receivers/upper-receivers/m4-enhanced-patol-rifle-5-56-upper-receiver-groups-prod136815.aspx?avs%7cManufacturer_1=COLT
アッパー単体販売にはCenturion Arms free float M-LOKR handguardsってありますよ
https://centurionarms.com/5-56-mlok-rail-9-5in-15in/