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Work order — Beretta Cx4 Storm

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: medium.

Shop difficulty: Tier 2 of 3

A blowback carbine whose steel receiver/barrel sits in a polymer stock shell. The owner strip is easy, but the reversible extractor, ejector and port cover are orientation-sensitive (the cover must sit opposite the extractor), and the bolt's spring/spring guide is held by a clip. No published parts list. 73 parts (complete carbine incl. magazine per Beretta's factory exploded view of the Cx4 Storm (9mm/.40/.45) reproduced on berettaweb.com: key numbers 1-73 on the drawing. The page's text parts table (Beretta p). Pew-Takedown's rating, not the manufacturer's.

Bench time: strip ~35 min, rebuild ~55 min (estimate). Actual: strip ______ rebuild ______

Special tools:

• Drift punch — Ejection port cover
• Beretta sight tool (supplied) — Rear/front sight adjustment

Watch for:

• The ejector, extractor and ejection port cover swap sides; the cover must always be on the side opposite the extractor or cases mis-eject, and its protrusions must enter their recesses. (reassembly; Beretta USA / Fabbrica d'Armi Pietro Beretta S.p.A.)
• The bolt's spring/spring-guide assembly is held by a retaining spring clip that is levered off and pushed back into its seat. (both; Beretta USA / Fabbrica d'Armi Pietro Beretta S.p.A.)
• Beretta advises working over a table and memorising part positions because components drop. (both; Beretta USA / Fabbrica d'Armi Pietro Beretta S.p.A.)

1. Clear and make safe

1. Point the muzzle in a safe direction and keep your finger off the trigger.
2. Place the selector or safety on safe.
3. Press the magazine release and remove the magazine.
4. Pull the charging handle fully to the rear and lock the action open if the design allows.
5. Inspect the chamber and magazine well with a light, then physically confirm the chamber is empty.
   Warning: Look and feel. Both, every time.
6. Remove all live ammunition from the work area.

2. Disassemble

Field Strip

1. Complete the Clear and Make Safe procedure with the safety on.
2. Remove the buttstock retaining pin or fastener and separate the buttstock from the receiver.
   Warning: The recoil spring assembly is under compression behind it.
3. Withdraw the bolt and recoil spring assembly rearward out of the receiver.
4. Clean the bore, chamber, bolt face, and receiver interior.
5. Stop here for routine cleaning. The trigger group is a modular assembly and is not owner-serviceable in any casual sense.

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.

4. Reassemble

Reassembly

1. Insert the recoil spring assembly and bolt into the receiver and seat them.
2. Refit the buttstock and install its retaining pin or fastener fully.
   Warning: Confirm the buttstock is secure before firing.
3. Cycle the action several times and perform the function check.

5. Torque

No manufacturer torque values are recorded for this firearm.

Notes: The manufacturer's documents give no torque value. They say: "Using the screwdriver, completely screw and tighten the screw in a clockwise direction on the stock." (Carbine User Manual CX4 Storm (UT007448/00), PDF p. 39 (stock length / spacer change, rear stock screw))

Fit or check on rebuild

• Reversible parts orientation — Port cover opposite the extractor
• Sights re-zero — Sights moved for coating

6. Function check

• Verify the firearm is unloaded with no magazine inserted before each step.
• Cycle the action by hand and confirm the bolt returns fully into battery.
• With the safety on, press the trigger. The hammer must not release.
• Move the safety to fire, cycle the action, and press the trigger. It should release.
• Hold the trigger back, cycle the action, and release slowly to feel the disconnector reset.
• Confirm the magazine seats and locks positively.
• Confirm the buttstock is securely retained and the ejection port is configured for the side you are shooting from.

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

Sources

1. Beretta Cx4 Storm Use and Maintenance Manual — Fabbrica d’Armi Pietro Beretta primary
2. Carbine User Manual CX4 Storm (UT007448/00) — Beretta USA / Fabbrica d'Armi Pietro Beretta S.p.A. primary
   https://dam.beretta.com/content/dam/beretta-usa/user-manuals/CX4_Storm_Manual.pdf
3. Beretta Web - Exploded Views - P. Beretta model CX4 cal. 9mm - .40SW - .45ACP — BerettaWeb.com (unofficial Beretta site, Ugo Muffolini), reproducing Beretta product codes and exploded-view positions secondary
   https://www.berettaweb.com/sezionati/sez%20CX4.htm

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.