300BLK Piston Kit – P Series Adjustable Micro Block


SKU: FGAA-03300 Categories: ,


Availability: Backordered 4-6 weeks



This system will work with 300BLK and a Pistol Length Gas System.

Kit includes:

  • Patented One-Piece Low Mass Bolt Carrier
  • P Series Micro Block – Adjustable (5 Settings – 100%/74%/53%/32%/11%)
  • Bolt Spring
  • Drive Rod with Bushing and Lightened Spring
  • Installation Instruction Card
  • Our Piston Kits No Longer Require the Receiver Bushing or Installation Dowel


The Adams Arms Piston System:

  • A short stroke free floating piston system.
  • Is Self-Cleaning.
  • Carbon and gases are expelled forward, away from operator.
  • Corrosive resistant coating processes.
  • Harmonics are not transferred into the barrel.
  • Doesn’t vent directly to atmospheric pressure; this eliminates flash signature and super sonic crack which is optimal for night vision and suppresses fire.
  • Has a Lifetime Warranty.


For 300BLK we only recommend a Pistol Gas Length (4.846″ from barrel extension to shoulder) and a Low Mass Carrier for optimal performance.

We recommend using a standard barrel nut or barrel nut with similar measurements for proper fit and function of the kit. Many aftermarket proprietary barrel nuts do not offer the clearance for the drive rod or proper seating of the spring and bushing.

Micro Gas Blocks should have the set screws torqued to 55-60 in-lbs


Installation Instructions: CLICK HERE


*We only guarantee the reliable cycling of Sub-Sonic ammunition with the use of a suppressor. As 300 Blackout is not a mil-spec cartridge, some tuning may be necessary depending on grain weight and suppressor used. We recommend barrels longer than 7.5″. Contact Support@adamsarms.net for any questions.

Additional Information

Weight 2 lbs
Dimensions 18 × 5 × 3 in
Product Type

Piston Kits

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