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Beretta Cx4 Storm

• moderate
• Shop tier 2
• medium confidence
• Pistol-Caliber Carbine
• blowback
• pistol caliber
• ambidextrous convertible
• shares pistol magazines

field strip ~3 min · reassembly ~5 min · detail strip ~25 min

Specifications

Model-specific safety

• The Cx4 is fully ambidextrous and the ejection port, charging handle, and magazine release can all be reconfigured for left or right side operation. Confirm the current configuration before shooting it, particularly if it is not your carbine.
• It feeds from Beretta pistol magazines. Confirm you have the correct magazine type for your model.
• The recoil spring assembly is under compression.
• This is a simple blowback in pistol calibre, so it fouls quickly.

Under spring tension

• Recoil spring assembly
• Magazine spring
• Hammer spring

Easily lost parts

Buttstock retaining pin · Bolt components · Recoil spring assembly

Tools

No tools required for the field strip.

Shop difficulty

Shop tier 2 Tier 2 — moderate among rifles and carbines, for the full job: strip to the parts that get coated and put it back together working. 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.

Parts: 73 numbered 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), from 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 berettaweb.com [3].

Bench time: about 35 min to strip, 55 min to rebuild (estimate). Estimate: field strip, bolt (extractor, ejector, spring/guide, clip, cocking handle), ejection port cover, recoil pad and spacers, sling swivels, trigger group out of the stock shell, sights. Rebuild longer for orientation of the reversible parts.

Small parts: 8 pins, 12 springs, 2 detents or plungers (counted by name in the text parts table (64 positions). Pins: swivel pin 004, sight pin 015, trigger bar pin 036, trigger pin 038, hammer pin 041, cheek rest retention pin 047, pin 050, inertia bolt s)

What comes off for coating

• Bolt and barrel: bolt, extractor, ejector, spring/spring guide and retaining clip, cocking handle, ejection port cover, recoil spring assembly, sights — drift punch
• Stock shell: trigger group (removed as a unit), recoil pad and spacers, sling swivels and screws, magazine release

Special tools

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

Known pain points

• 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)
  Source: Carbine User Manual CX4 Storm (UT007448/00) — Beretta USA / Fabbrica d'Armi Pietro Beretta S.p.A. dam.beretta.com [2] — “MUST always be mounted on the opposite side of the extractor in order to avoid possible mis-ejection of the case.”
• 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)
  Source: Carbine User Manual CX4 Storm (UT007448/00) — Beretta USA / Fabbrica d'Armi Pietro Beretta S.p.A. dam.beretta.com [2] — “Remove the retaining spring clip from the spring / spring guide assembly”
• Beretta advises working over a table and memorising part positions because components drop. (both)
  Source: Carbine User Manual CX4 Storm (UT007448/00) — Beretta USA / Fabbrica d'Armi Pietro Beretta S.p.A. dam.beretta.com [2] — “It is advisable to carry out the field stripping and the assembly operations over a table to catch components should they drop.”

Fit or check on rebuild

• Reversible parts orientation — Port cover opposite the extractor
  Source: Carbine User Manual CX4 Storm (UT007448/00) — Beretta USA / Fabbrica d'Armi Pietro Beretta S.p.A. dam.beretta.com [2] — “MUST always be mounted on the opposite side of the extractor in order to avoid possible mis-ejection of the case.”
• Sights re-zero — Sights moved for coating

This is Pew-Takedown's rating, not the manufacturer's. How tiers are rated. Forum reports are owners' experience, not specifications.

Procedures

Torque specifications

No sourced torque values from the manufacturer are recorded for this firearm. Where a fastener has a specified torque — action screws, scope bases, muzzle devices, barrel nuts — get it from the manufacturer or a gunsmith rather than estimating it.

What the manufacturer does say: 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))

Materials and factory finish

As stated by Beretta. Prep, masking and cure depend on these; a polymer or aluminium part, a nitrided or anodised finish, and a blued steel part are each a different job. Variants with other finishes may exist — check the maker's page for the exact SKU on the bench.

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.

Maintenance

Lubrication points

• Bolt body where it rides in the receiver
• Recoil spring guide
• Hammer and sear pivots

Cleaning notes

Pistol-calibre blowback actions foul heavily and quickly. Clean the bolt face and receiver interior regularly and keep lubrication moderate.

Suggested inspection interval: roughly every 1000 rounds. This is a general guideline, not a manufacturer specification.

Wear parts to inspect

Recoil spring assembly · Extractor and spring · Bolt face · Magazine springs

Common issues

Also covers

The procedures above are reported to apply to: Cx4 Storm in 9mm, .40 S&W, and .45 ACP. Verify against the manual for your specific model.

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Sourcing