Last updated July 2026 · By Nick Hall, covers new rifles and AR platforms for USA Gun Shop
Quick take: US Palm just put its name on a complete firearm for the first time, and the compact STORM CAT4 pistol landed on the cover of Firearms News for July 2026. It is an 11.5-inch, 5.56 NATO AR-15 pistol with fully ambidextrous controls, a Magpul BTR brace, and a $1,399 MSRP. For home-defense and truck-gun buyers, that is a lot of duty-grade hardware at a working price.
What the STORM CAT4 actually is
US Palm built its reputation on AK grips and rugged polymer, so a billet AR is a real turn. The STORM line marks the company’s move into building complete rifles and pistols instead of just parts. CAT4 is the top trim in that line. It sits above the simpler CAT3, which keeps standard AR controls for shooters who want a clean, clutter-free receiver. Both guns are distributed through Century Arms, and both ship in all-black or a Storm Green finish. Name and paint aside, this is meant to be a serious working gun.
The specs that matter
The pistol is short, ambidextrous, and built from billet aluminum. US Palm machines the upper and lower from 7075-T6 billet with a Type III hardcoat anodized finish. The barrel is 11.5 inches, cold hammer forged, with a 1:7 twist and a mid-length direct-impingement gas system. It wears the company’s Mono-Loc M-Lok handguard with a full-length top rail, a Hiperfire single-stage trigger, and the Hurricane Hybrid muzzle device that works as both flash hider and brake. A Magpul BTR telescoping arm brace anchors the back, feeding from standard 30-round 5.56 magazines. Weight runs about 6 pounds, and overall length adjusts from roughly 29 to 32 inches with the brace. The safety, magazine release, and bolt catch all run from either side, and the safety uses a short 45-degree throw. US Palm rounds it out with an in-house reduced-angle grip and a flared magwell to speed reloads. None of that is exotic, but the parts list reads like a well-specced upper mid-tier build rather than a budget kit.
Why a duty-ready 5.56 pistol makes sense
An 11.5-inch 5.56 pistol splits the difference between a handgun and a rifle. Inside a home or a vehicle, a short barrel is easier to move and store than a 16-inch carbine, while 5.56 out of an 11.5-inch tube still hits far harder than any pistol round. The BTR brace lets a shooter shoulder the gun for control without stepping into NFA short-barreled rifle territory. That combination is why the AR pistol category exists, and it is why buyers shopping our list of the best cheap AR pistols keep the format in the conversation. A cold hammer forged barrel and mid-length gas also help here, since the mid-length setup runs a bit softer than the carbine-length gas found on many short ARs, which matters when you are keeping rounds on target fast up close. If you want the full rifle picture first, our roundup of the best AR-15 rifles shows where a short pistol build fits.
How it stacks up
At $1,399, US Palm is aiming at the duty-grade middle, not the bargain bin. American Rifleman reports the company is pitching $2,000-class performance at roughly a $1,300 price. That puts the CAT4 against mid-tier ARs from BCM, PSA’s premium builds, and the cheaper Daniel Defense lines. Billet receivers, a cold hammer forged barrel, and fully ambi controls are features that usually cost more. What you give up is a track record, since this is a brand new platform with limited independent testing so far. Oleg Volk’s cover feature is one of the first hands-on evaluations in print.
Who it is for and what is next
This is a home-defense and truck-gun buyer’s gun, not a match rig. If you want one AR pistol that handles close-quarters defense and doubles as a compact range gun, the CAT4 checks the boxes. Shooters who like to tinker will find standard AR-15 fitment throughout, so upgrades from our guide to AR-15 parts drop right in. Century Arms already lists the pistol through major retailers, so availability looks real rather than vaporware. Watch for third-party accuracy and reliability numbers over the coming months before you treat the duty-ready billing as proven.
Frequently Asked Questions
What is the US Palm STORM CAT4?
It is a complete AR-15-pattern firearm from US Palm, sold as either an 11.5-inch 5.56 NATO pistol or a 16-inch rifle. CAT4 is the premium trim with fully ambidextrous controls, distributed by Century Arms.
What caliber is the STORM CAT4 pistol?
It is chambered in 5.56 NATO, which also accepts .223 Remington, and it feeds from standard 30-round AR-15 magazines.
How much does the STORM CAT4 cost?
MSRP is $1,399 for both the pistol and the rifle, with street prices at major retailers typically running lower.
Does the CAT4 pistol have a brace or a stock?
The pistol version uses a Magpul BTR telescoping stabilizing arm brace. The rifle version instead uses a Magpul DT collapsible stock on a 16-inch barrel.
What is the difference between the CAT3 and CAT4?
The CAT4 is the premium model with fully ambidextrous safety, magazine release, and bolt catch, plus a reduced-angle grip. The CAT3 keeps standard AR controls and a cleaner receiver for shooters who want simplicity.
What barrel and gas system does the CAT4 pistol use?
It has an 11.5-inch cold hammer forged barrel with a 1:7 twist and a mid-length direct-impingement gas system, capped with the Hurricane Hybrid flash hider and brake.
Is a 5.56 AR pistol legal to own?
AR pistols with an arm brace are legal in most states as pistols, not short-barreled rifles, but state and local laws vary. Check your state rules on braces and barrel length before you buy.
Is the STORM CAT4 available to buy now?
Century Arms distributes the CAT4, and it is listed by major online retailers such as Palmetto State Armory and GrabAGun. Availability and finish options can vary by dealer.
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