Description
S&T T21 Tappet Plate (S33 – Black)
This is a replacement tappet plate in black for the S&T T21 electric rifle, listed with the part reference S33. The tappet plate is the part inside the gearbox that moves the air nozzle back and forward, opening the hop-up chamber to let each BB in and then pushing it into place before the shot.
S&T makes the T21 as a bullpup AEG, and a dedicated replacement part lets you repair it without guessing at compatibility with generic parts. A worn or broken tappet plate is a common cause of feeding problems, double-feeding and BBs dribbling from the barrel, so replacing it is often a quick fix for a rifle that has stopped feeding properly.
What the tappet plate does
Each time the sector gear turns, a cam on the gear pulls the tappet plate back, drawing the nozzle away from the hop-up so a BB can drop in from the magazine. A spring then returns the plate, pushing the nozzle forward to seat the BB in the hop-up rubber and seal the chamber. If the plate is cracked, worn or its spring is tired, the nozzle may not move fully, and feeding becomes unreliable.
Tappet plates are a wear item in any AEG, especially in rifles run at a high rate of fire or with heavy use over many games.
Fitting
Replacing a tappet plate means opening the gearbox. Remove the battery and magazine, follow the T21’s disassembly guide, and decompress the spring safely before splitting the shell. Note how the tappet plate spring is fitted before removing the old plate, and test the nozzle movement by hand before closing the gearbox.
If you are not confident working inside a gearbox, have the part fitted by an experienced airsoft technician. Opening a gearbox means dealing with a compressed spring and a lot of small parts, and incorrect shimming or reassembly is the most common cause of noise and early wear.
Key features
- Replacement tappet plate for the S&T T21
- Part reference S33
- Black finish
- Restores reliable nozzle movement and feeding
- Common fix for misfeeds and double-feeds
- Dedicated part, no guesswork on fit
Compatibility
Listed for the S&T T21. Gearbox layouts vary between bullpup models and generations, so compare the part in the images with the tappet plate in your rifle before ordering, and ask us if you are not sure.
Care and maintenance
Use a light touch of grease where the tappet plate slides against the shell and gears, but keep grease away from the nozzle and hop-up. Check the tappet return spring whenever the gearbox is open, as a weak spring causes feeding problems.
Store the rifle with the battery disconnected, and clean the hop-up and inner barrel regularly so feeding issues are not mistaken for a tappet fault.
Who is it for?
S&T T21 owners and technicians repairing feeding problems or replacing a worn or broken tappet plate.
Please note: Tappet plate only; the tappet spring and other gearbox parts are not included unless shown. Always wear suitable eye protection when testing airsoft replicas.
