HK416, MR556 ARC-Fire Trigger - V2 with Mil-Spec Selectors - Ambi Controls

AS Designs V2 ARC-Fire Trigger for HK416 and MR556 with Mil-Spec Ambidextrous Selector Levers

The ARC-Fire (Active Reset Clutch) trigger is an innovative trigger system designed to reset the trigger immediately after each shot, allowing for rapid follow-up shots while maintaining one round fired per trigger action.

The V2 ARC-Fire trigger improves upon the original design with updated selector position options that better align with HK factory receiver markings, a smoother detent track, and larger cam surfaces for improved function and extended service life. This HK416/MR556-specific kit now includes mil-spec ambidextrous selector levers designed to function with the ARC-Fire mechanism.

Standard AS Designs AR-15 ARC-Fire kits are not compatible with the HK416 and MR556 platform. This kit includes the components necessary for proper function in compatible HK416 and MR556 rifles.

NOTE:

• Only the included selector levers and ASD's mil-spec levers are compatible with the ARC-Fire kit as the selector lever is part of the ARC mechanism.
• Does not require a full-auto BCG but a FA BCG will keep the trip lever from flipping backwards in the receiver and disengaging.  
• IF your rifle has a semi-auto BCG: Actuating the charging handle with the muzzle pointed upwards will disengage the trip lever.  To re-engage the trip lever, simply actuate the charging handle again with the muzzle pointed towards the ground to reposition the trip lever into the correct orientation.  

Features:

• V2 ARC-Fire trigger system
• Designed specifically for HK416 and MR556 platforms
• Mil-spec ambidextrous selector levers
• Multiple selector position configurations available
• Smoother detent track than the V1 design
• Larger cam surfaces for improved durability
• Immediate trigger reset after each shot
• One round fired per trigger action

Compatible With:

• HK416 A5 (1.8mm gas vent screw recommended)
• HK MR556 A4 (1.8mm gas vent screw recommended)
• HK MR556 A1 (will require an adjustable gas block to cycle)
• HK416 A1, A3 (will require an adjustable gas block to cycle)

Restricted States:

• CA, CT, DE, FL, HI, IL, MA, MD, MN, NJ, NV, NY, OR, RI, DC
• No US Territories or international orders.

Depending on your configuration and ammo selection, you may need to increase or decrease the gas vent screw size.  MR556 A4 rifles and pistols are equipped with a 1.3mm gas vent screw from factory.  A 1.8mm gas vent screw was optimal for our MR556 A4 11" and 16" barrel rifles using standard M195 ball 55gr 5.56 ammo.  User experience will vary, therefore, it may take some trial and error to identify the perfect size gas vent screw for your particular configuration and ammunition.  Most configurations will cycle well with a gas vent screw in the 1.6mm-2.0mm range.

Ejection patterns should be approximately 3-4 o'clock. If you observe your casings ejecting closer to 1 o'clock (over-gassed), go UP in vent screw size to CLOSE gas block. If ejecting closer to 5 o'clock (under-gassed), go DOWN in vent screw size to OPEN gas block.