$1.00
Trade – Roller Delayed 9mm MK12
- Phone Number: Click to view
- Condition: Like New
- Listing Type: Individual
- City: Layton
- State: Utah
- Zip/Postal Code: 84040
- Local County (e.g., Summit County): Davis
- Make/Brand: BCM / H&R
- Caliber: 9mm
- Terms: Must agree to terms
- Listed: April 7, 2026 9:38 pm
- Expires: 3 days, 3 hours

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Description
Looking to trade my super unique and very fun roller delayed mini MK12 SMG. It takes Colt pattern 9mm mags and has a roller delayed buffer system that makes it MP5 quiet and smooth. It retains the reliability of a blowback gun but is a very soft shooter, and very hearing safe with a can due to the Maxim roller delayed buffer. You should run this suppressed as the barrel sits a little inside the handguard, or you could put a 9mm blast can/linear compensator on it. I love this gun but just have more interest in lever guns than ARs right now. Here’s the build list with all of the parts and prices:
BCM Upper Receiver: $130
H&R 635 Lower: $220
ALG ACT Trigger : $88
CMMG LPK: $35
Brownells Receiver Extension: $26
Milspec CH: $20
BCM QD Endplate: $17
HAR-15 Brace: $40
Mottled A1 Grip: $20
Maxim RDB: $190
BKF Bolt: $120
Odin 416 SS 7.5″ 9mm Barrel: $169
PRI Carbine Length Handguard: $335
PRI 3 Hole Riser: $77
Metalform 20rd Mag: $31
Total: $1,518 (before tax/shipping)
Looking for a Henry Big Boy X in .357 mag or the new Protector H12 in .357 mag. Or, let me know if you have something else cool.
I have about 200 rounds through it, very solid ejection and function and it eats any 9mm brand I can throw at it. Scope and suppressor not included. Text only please, located near Hill AFB.




