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Work order — Beretta A400

Taking the firearm apart for a job such as refinishing, and putting it back together to specification. Generated from the Pew-Takedown entry last updated 2026-10-29. Confidence: high.

Shop difficulty: Tier 2 of 3

Gas gun with the recoil spring on the magazine tube (no buttstock tube to fight), a trigger plate that drops out on one pin, and a do-not-touch gas valve. The traps are moderate: bolt, rods, spring and piston stop stacked on the tube together, a trigger plate that needs the hammer cocked and the release held, orientation of gas parts, and the cocking-handle groove. Low Tier 2. Pew-Takedown's rating, not the manufacturer's.

Bench time: strip ~45 min, rebuild ~60 min (estimate). Actual: strip ______ rebuild ______

Special tools:

• Long stock-bolt socket on extension — Stock bolt
• Punch set — Trigger plate and bolt pins

Watch for:

• The trigger plate goes back only with the hammer cocked and safety on, the release button held down while the plate is rotated in, and the retaining pin inserted only when the holes are centred. (reassembly; Beretta)
• Breech bolt, operating rods with sleeve, recoil spring and piston stop are stacked on the magazine tube and pushed in together, which takes some juggling on a flat surface. (reassembly; Beretta)
• The self-cleaning gas valve assembly must not be stripped; Beretta sends it to a gunsmith. (disassembly; Beretta)

1. Clear and make safe

1. Point the muzzle in a safe direction and keep your finger off the trigger.
2. Engage the crossbolt safety.
3. Pull the bolt handle rearward to eject any chambered shell and lock the bolt open.
4. Cycle the action repeatedly, catching each shell as it ejects, until no more shells feed from the magazine tube.
5. With the action open, inspect the chamber and look up the magazine tube with a light.
   Warning: The chamber AND the tube.
6. Physically confirm the chamber is empty and remove all live ammunition from the work area.

2. Disassemble

Field Strip

1. Complete the Clear and Make Safe procedure, inspecting through the ejection port, the loading gate and the chamber. Check that the hammer is decocked.
   Tip: Work over a table. Beretta advises it so components are caught if they drop.
2. Check that the carrier stop pin is pressed all the way down. If it is not, push it down.
   Tip: This comes first, before anything is unscrewed. It is the step the generic shotgun procedure leaves out.
3. Pull the breech bolt all the way back so that it stays open.
4. Unscrew the front cap of the fore-end anticlockwise.
5. Holding the shotgun by the barrel, pull the fore-end straight out toward the muzzle.
6. Pull the barrel out of the stock and receiver assembly while holding the piston inside the gas cylinder.
   Tip: Hold the piston as the barrel comes off, or it comes with it and lands on the floor.

Breech bolt stripping

1. The breech bolt assembly only needs to come apart in order to clean its components. Beretta says so explicitly.
2. Keeping the index or middle finger of your left hand on the cocking handle, press the release button and let the breech bolt move forward slowly until it stops.
   Warning: Control it with a finger on the cocking handle. Letting it run forward is how parts get damaged.
3. Press the head of the breech bolt until the groove on its neck lines up with the edge of the bolt body.
   Tip: The cocking handle will not come out until that groove is aligned. If it feels immovable, the head is not pressed far enough.
4. Keeping the head depressed in that position, pull the cocking handle out of the breech bolt — forcefully.
5. Working over a flat surface with the ejection port pointed upwards, pull forward on the breech bolt assembly, the operating rods with sleeve, the recoil spring and the spring holder together, to force the breech bolt out of the receiver.
   Tip: Ejection port up, and all of it forward as one. This is not a rearward extraction.
6. If you also need the trigger plate out: engage the safety with the hammer cocked, press the carrier stop pin if it is not already pressed, drive out the trigger guard retaining pin with a pin punch or awl, and remove the trigger plate by pressing on the trigger guard toward the barrel first.
   Tip: Beretta notes the trigger plate only needs disassembly to clean the trigger mechanism.

3. Refinish

The components the procedures above separate. Coating, masking and cure are outside this database; follow your coating system's instructions. A part the manufacturer marks "factory fit" should not be swapped or reworked.

No manufacturer statement of materials or finish is recorded. Identify each part's material before choosing prep and cure.

4. Reassemble

Breech bolt stripping

1. Reverse the steps of "Breech bolt stripping".

Reassembly

1. Install the trigger group and its pin.
2. Slide the bolt assembly into the receiver and install the bolt handle.
3. Reinstall the gas piston and seals in their correct orientation.
   Warning: Reversed components will not seal.
4. Seat the barrel fully and install the forend.
5. Hand-tighten the magazine cap firmly.
6. Cycle the action several times and perform the function check.

5. Torque

Notes: From Beretta's semiautomatic shotgun user manual (A300, A350, A400, 1301), which prints the unit as "N/m"; in a torque specification that can only mean newton-metres.

Fit or check on rebuild

• Gas valve not disturbed — Beretta forbids disassembling the self-cleaning valve; leave it assembled and mask it.
• Stock drop/cast spacers returned as fitted — The spacer set determines the customer's fit; mark and refit them as removed.
• Function check: safety, trigger/sear release, disconnector and feeding with dummy rounds — Standard after any detail strip; a mis-assembled sear or disconnector can double or fail to fire.

6. Function check

• Verify the shotgun is unloaded — chamber and magazine tube — before each step.
• Cycle the action fully and confirm it locks closed.
• With the hammer cocked, engage the safety and press the trigger. The hammer must not fall.
• Disengage the safety and press the trigger. The hammer should fall.
• Load two dummy shells into the magazine and confirm they feed and eject one at a time.
• Confirm the magazine cap or takedown fastener is tight.

If any check fails, the firearm is not safe to fire. Stop and see a licensed gunsmith.

Sources

1. Beretta Semiautomatic Shotgun User Manual (A400, A350, 1301) — Beretta primary
   https://dam.beretta.com/content/dam/beretta-usa/user-manuals/semiauto_Manual.pdf

Educational guide only. Some information comes from non-authoritative sources. Always consult your manufacturer's manual and a licensed gunsmith. Verify your firearm is unloaded before every procedure. Full disclaimer: https://github.com/Fundamental-build-LLC/Pew-Takedown

Legal notice: this material is third-party information compiled from sources of varying reliability and is provided for general informational and educational purposes only. It is not gunsmithing, technical, safety or legal advice, it is not verified or endorsed by any manufacturer, and it must not be taken as fact. Any work on a firearm beyond the routine field stripping described in its own owner's manual should be performed only by a licensed and insured gunsmith. You use this material entirely at your own risk. Fundamental Build LLC and the project's contributors make no warranty of any kind and accept no liability for death, injury, damage or loss arising from its use. Full terms: LEGAL.md.