MP-661K High Performance Blackbird Bumblebee Barrel Breech Seal MagnusOps Qty 1

High performance breech seals (Qty 1) for Baikal MP-661K Drozd (Blackbird or Bumblebee).

• Creates a tighter seal between the barrel bushing and valve body, reducing air leakage and increasing muzzle velocity, compared to OEM seal.
• Significantly reduces shot-to-shot muzzle velocity extreme spreads resulting in more consistent shot velocities and improved accuracy, compared to OEM seal.
• Designed to withstand extreme pressures of 1600+ PSI and remain flexible at subzero temps encountered during sustained high rates of fire or when using CO2.
• Offers greater barrel breech protection compared to OEM seal by eliminating the freebore distance, inside the barrel bushing, that the BB would normally travel before entering the barrel. The BB is maintained along the central axis of the bore by the extended length seal until entering the barrel. 
  

Each kit includes 1 seal that have been coated with silicone grease.

Mason Dawson has performed a test, comparing the OEM Amber, OEM Black, Early Prototype, and Final Production Seal being offered now.  Results are perfect! 

NOTE:  For best performance, the seal should protrude from the rear of the barrel bushing leaving an air gap of approximately 0.5 - 1mm, between the seal rim and the barrel bushing.  Upon insertion of the mag, the seal will be compressed by the gap amount, creating a tighter seal.  If your barre| breech is excessively long (OEM Barrels have been found to have inconsistent threaded breech lengths) causing greater than 1mm of seal protrusion and/or binding when inserting the mag, removal of material from the breech end of the barrel to reduce its length would be the best solution.  Alternatively, you could add additional shims that sit in front of the barrel bushing (shown in above photo) or replace your existing shims with thicker ones.  Almost anything could be made to work as a shim, e.g. plastic or metal washers, aluminum coil stock/flashing, or plastic of sufficient thickness could also be cut to fit.  If you end up stacking shims, once you've got a good combination that achieves sufficient thickness, you could bond them together using epoxy or similar to create a single solid shim so you don't have to worry about losing a portion of it.  For reference, each shim in the Blackbird is approximately 0.6mm thick for a total stacked thickness of 1.2mm.  If you do increase the shim thickness, be sure to check that the valve body and barrel bushing matting surfaces are flat and parallel to each other and everything including the solenoid still lines up along the barrel axis. We ship from Izhevsk, Russia.