Hop-Up Assembly

1. Pull the inner barrel from the hop chamber.
2. Slide the bucking onto the barrel — Airsoft Mutation LC 60° is the reference. The bucking lip seats in the barrel window; the AEG-cut tab seats in the chamber slot.
3. Lubricate only the outer surface of the bucking with a light film of silicone. Never grease the bucking lips or the contact patch.
4. Drop the assembly back into the hop chamber. The bucking must seat with no twist and no lip rollover.

1. Drop the 3mm Infinity nub (or the bucking's matched nub) into the chamber nub seat with the concave face down toward the patch.
2. Verify the nub presses the patch evenly across its full width with the hop arm at the lightest pressure setting. Any uneven press = nub orientation wrong or chamber wear; correct before closing.

If the chamber is a Maxx M4A: unscrew every screw on the unit, Loctite (Blue) each one, re-tighten. Maxx ships with screws barely above hand-snug; they walk loose inside one range trip and the dial loses zero.

1. Close the chamber with hop set to zero.
2. Chrono five rounds of the customer's actual play-weight BB at field FPS. Document the average.
3. Walk hop up one click at a time. The BB stops dropping at approximately 35 m and starts to rise. Stop one click before the rise.
4. Re-chrono. Hop pressure adds 5–15 FPS — adjust spring only if final FPS exceeds field cap.

The 60° / 3mm Infinity combo holds:

• 0.28g cleanly to ~60 m
• 0.32g cleanly to ~70 m
• 0.36g cleanly to ~80 m
• 0.40g cleanly to ~90 m

Do not chrono with 0.20g and tune hop with 0.32g on the same build. Match chrono ammo to actual play ammo.