The short barrel configuration of the ARAK-21 upper is 12.5"
The Faxon ARAK21 Upper is intended for use with any standard AR-15 lower receivers. It will not function with the ks47 lower.
Barrel length.
No, the ARAK-21 is not compatible with Full-auto fire control groups or other fire control groups that use similar architecture.
The screws for the lower handguard should be torqued to at least 25 in/lbs
I am not sure what Optics Planet is referring to with "Groups 1" in this product title. They currently list only two versions of the ARAK-21 with this listing being the standard black anodized finish and the other being an exclusive Sand Cerakote finish.
This is the correct listing for that! It is the first option listed on the page with MPN: URSSB762
This is Optics Planet's listing for the standard Black anodize finish ARAK-21 upper. The "Complete Upper Receiver" listing is for the Optics Planet exclusive Sand Cerakote finish ARAK-21 upper.
this is the listing for the 16" barrel uppers.
Yes, all ARAK-21 uppers produced after 2021 have ambidextrous ejection ports and can be swapped between right side and left side ejection.