SRS pull bolt air displacement is 41 cc, the second largest volume for bolt action on the market after our HTI. This bolt can accept any APS 13 mm springs. Stock spring type and muzzle energy may differ from one country to another, please check directly with your retailer. The cylinder is made of stainless steel (23.8 mm bore), and the monolithic bolt handle is made of steel, equipped with M8 bolt knob. The piston has an aeronautical grade aluminium body and head, a steel piston end, and a 70° synthetic rubber piston cup. The spring guide is made of fiber glass reinforced Nylon, it’s equipped with 2 dampening orings and a thrust bearing. The bolt dust cover is perforated, and the red piston is acting as a priming indicator.
 
The piston sear is made of steel, and the aluminium trigger is adjustable in preload. The trigger housing is made of fiber glass reinforced Nylon. The piston sear height can be adjusted by moving the trigger box forward or backward. The steel safety is ambidextrous.
 
Outer barrel (CNC, aeronautical grade aluminium) is very deeply fluted and threaded (M14x1 CCW thread). It’s equipped with .308 QD muzzle brake (SBA-FHD-06). Proper timing of the muzzle brake is compulsory when used with QD DTSS suppressor replica. Inner barrel (6.05 x 578 mm, brass) and hop-up rubber (silicone 60°) are of AEG type.
 
The two-way CNC aluminium hop-up unit, directly attached to the quick-change barrel assembly, is allowing barrel switch in seconds while keeping your hop up setting. Hop up setting is done by two screws on top of the rifle, through the receiver, with the provided key, without removing the barrel. Hop-up can alternatively be used with two larger setting screws at the cost of quick-change keeping hop setting ability.