How to Install a Breech Seal in a FWB 300S

The Feinwerkbau model 300s, otherwise referred to as the FWB 300s, is a high-grade competition, match-style pellet rifle. These rifles are often used for airgun competition, plinking and for small varmint hunting. As with all airguns, problems may arise from time to time that require maintenance. Over time, seals in the gun such as the breech seal will wear out and become discolored. Once this occurs the weapon will lose pressure and firing will be affected. Installing a new breech seal in the FWB 300s can be accomplished with little difficulty.

Things You'll Need

  • Screwdrivers
  • Padded gun vise
  • Needle-nose pliers
  • Hooked tool (dental pick)
  • Replacement breech seal
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Instructions

    • 1

      Unload the weapon completely. Visually inspect the weapon to ensure that no live ammunition is present.

    • 2

      Secure the weapon upside-down in a padded gun vise. ensure that the belly retaining screws are accessible.

    • 3

      Remove all of the screws on the bottom of the weapon frame. Pull off the bottom portion of stock.

    • 4

      Remove the C-washer and pin located just in front of the chamber. Pull the pin out using needle-nose pliers.

    • 5

      Separate the piston housing from the barrel. Pull off the recoil track springs and recoil track from the piston housing.

    • 6

      Remove the old breech seal from the piston housing using a hooked tool such as a dental pick. Lubricate the piston. Insert the new breech seal. Reassemble the weapon.