The US Palm Cat4 Storm is an AR-15 pistol chambered in 5.56 NATO with an 11.50-inch cold hammer forged threaded barrel and a 30+1 capacity. It has a matte black receiver with a Picatinny rail, a Mono-Loc MLOK handguard, and ships with a Magpul BTR arm brace. The pistol includes a Hiperfire trigger and US Palm grip. 
 

Key Specifications 

• Brand: US Palm 
• Model: Cat4 Storm 
• Caliber: 5.56 NATO 
• Action: Semi Auto 
• Capacity: 30+1 
• Barrel Length: 11.50 inches (threaded, cold hammer forged) 
• Color/Finish: Matte Black 
   

Detailed Features 

• Cold hammer forged threaded barrel 
• Magpul BTR arm brace 
• Mono-Loc MLOK handguard 
• Hiperfire trigger 
• US Palm grip with Picatinny rail receiver

Owners of the US Palm Cat4 Storm highlight the Hiperfire trigger as a standout factory inclusion. Getting an upgraded trigger from the factory at this configuration is unusual and frequently mentioned as a genuine value-add. The cold hammer forged barrel is also appreciated for its durability reputation.

The Magpul BTR arm brace is comfortable and adjustable, which suits a range of users. The MLOK handguard gives the pistol a clean profile and practical accessory mounting. The overall package is compact and well-spec'd for a braced AR pistol.

Some owners find the US Palm grip narrower than preferred, which is a matter of personal fit. The 11.5-inch barrel in 5.56 NATO produces significant muzzle blast, which is a known characteristic of this barrel-length class rather than a deficiency of the Cat4 specifically.