Winter Rust 2026: SuomAR-K - A Hybrid 80% & Printed, Suomi Mag, Rotary Delayed, Forward Cocking / Slappable, AR9 / MP5k Mashup

Posted by il_100@reddit | GunnitRust | View on Reddit | 14 comments

Registered Form 1 SBR with bonus 2 x 7" AR tube handguard Form 1 can.

Feeds from sticks and drums - should also work with coffin mags but I ain't made of money...

CMMG RDB bolt and barrel, KAK CQC buffer, BCA side charger upper, all printed parts in CF Nylon.

Generic 80% lower milled off at the mag well, fence milled off, and a printed Suomi mag adapter bolted in through the mag release hole. Aluminum mag release.

Mag adapter was based on DingoDaze's adapter and I developed it in collaboration for a different project with Zer0fux (Odysee handles).

Stock, grip, forend and foregrip are all my designs, mostly based on MP5 parts - the grip is actually based on a PSG-1 design adapted for ARs and chopped.

The forend secures to a steel OHHUNT barrel nut, 8mm rod for a cocking tube through an enlarged gas port hole in the upper. Stock rides on 8mm stainless tube, 4 8x10 sleeve bearings are press fit into the stock housing so it's smooth on opening and closing and locks up solid.