The US Palm CAT4 Storm is an AR-15 rifle chambered in 5.56 NATO with a 16-inch cold hammer forged barrel. It holds 30+1 rounds and ships with a US Palm grip, Magpul stock, Hiperfire trigger, and a Mono-Loc M-LOK handguard. The finish is black throughout. 
 

Key Specifications 

• Brand: US Palm 
• Model: CAT4 Storm 
• Caliber: 5.56 NATO 
• Action: Semi Auto 
• Capacity: 30+1 
• Barrel Length: 16 in 
• Color/Finish: Black 
   

Detailed Features 

• 16-inch cold hammer forged barrel in 5.56 NATO 
• 30+1 round capacity 
• Hiperfire trigger installed from the factory 
• Magpul stock and US Palm grip 
• Mono-Loc M-LOK handguard for accessory attachment

Owners of the US Palm CAT4 Storm consistently single out the cold hammer forged barrel and the factory Hiperfire trigger as the standout features. Getting a quality trigger pre-installed is something buyers appreciate, since it removes one of the first aftermarket expenses on most AR builds.

The Magpul stock and US Palm grip combination gets good marks for comfort, though some shooters find the grip angle slightly different from a standard AR setup and need a short break-in period. The Mono-Loc M-LOK handguard provides solid real estate for lights and other accessories.

The CAT4 Storm occupies a crowded segment, and a few owners note the US Palm brand carries less name recognition than competitors at the same price. Those who do seek it out tend to be happy with the overall parts specification, though the resale market for US Palm rifles is thinner than for more mainstream AR brands.