US PALM just recently released the Storm CAT 4 AR-15, and it is making some serious waves. This rifle is outfitted with ambidextrous controls, a hybrid muzzle device that reduces felt recoil, and a Hiperfire trigger ready to race out of the box. I think US PALM delivered a perfect package at a fair price point with the Storm CAT 4 rifle, and I was really impressed with how the gun shot. My friend, TC, joined me on the range to test this latest gun offering from US Palm.
US PALM Storm CAT 4 Details & More
One of the most notable differences between the Storm CAT 4 AR-15 rifle and others on the market is the Mono-Loc handguard system. Its precision rear-locking interface keys directly into the upper receiver for a more rugged fitment. It doesn’t simply come together and sit flush, as most AR-15 handguards and upper receivers do. This creates a more stable shooting foundation and prevents unwanted twisting of the handguard or any flex in movement.
The handguard itself has a continuous top rail and a seven-sided profile, with M-LOK-compatible slots for mounting various accessories. The Mono-Loc handguard ensures that mounted accessories stay zeroed or maintain proper placement even under rigorous use. If you’ve ever had your handguard tilt or shift on you after a range day or training session, you don’t have to worry about that as much with this better-engineered design.
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US PALM outfitted the Storm CAT 4 rifle with the Hiperfire EDT Designated Marksman Triggerrather than using a standard MIL spec trigger. It is a single-stage trigger designed with a unique duplex trigger bow. The higher, top position gives you a shortened pull, but a higher weight. The lower, bottom position has a lengthened pull but a lower weight. This trigger alone retails for $99 and, in my opinion, adds significant value to the rifle.
Ambidextrous Controls
Nowadays, more rifle manufacturers are outfitting their guns with ambidextrous safety selectors and charging handles to appeal to a larger audience. These are also simple upgrades/part swaps that you can shop aftermarket for and install on just about any rifle you own. The US PALM Storm Cat 4 lower receiver has an ambidextrous magazine release and an ambidextrous bolt release. These aren’t controls you can just add later to other lower receivers, so these controls alone are what make the Storm CAT 4 rifle a cut above the rest.
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The bolt release on the right side is a flat lever that is easily manipulated by your trigger finger as a right-handed shooter. The magazine release on the left side of the lower sits under the left side bolt release and can easily be manipulated by a left-handed shooter’s trigger finger. The Storm CAT 4 rifle is equipped with an ambidextrous safety selector, already installed at a 45-degree throw angle. It’s finished off with an ambidextrous charging handle, making it a complete ambidextrously designed rifle.
Hurricane Hybrid Muzzle Device
The two modifications I make most often to a rifle are upgrading the trigger and installing a muzzle device. The right muzzle device can greatly decrease the felt recoil of a rifle. The Storm CAT 4 rifle uses the US PALM Hurricane hybrid muzzle device to manage flash suppression and reduce recoil. It physically mimics the look of a twisting hurricane rather than the traditional muzzle device design of a standard birdcage flash hider or straight compensator. The spiral geometry helps redirect gases, reducing muzzle rise and breaking up muzzle flash. It is an awesome design for shooting, but it can be a nuisance to stand next to when someone else is shooting (which isn’t a problem if you’re the shooter!). It performed way better than I expected and did a great job of making the gun shoot flatter, enabling faster follow-up shots.
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Storm CAT 4 On The Range
TC and I had a blast shooting the Storm CAT 4 rifle. I mounted the AEMS-PRO-X2-GD optic to it and zeroed it at 50 yards. This enclosed rifle sight is perfect for ARs, as it features a wide viewing window and includes a four-post lower 1/3 co-witness mount to position the optic at 1.63 inches. The reticle itself can be used as a 2 MOA dot, a 65 MOA circle, or a combined reticle. It’s outfitted with Holosun’s Solar Failsafe Shake Awake technology, so it is ready to use when needed and conserves battery life when not. This was my first time using the gold reticle from Holosun rather than a green or red reticle, and I have to say the gold is the best coloring for shooting in bright, sunny days.
I tested five different loads of ammunition at 50 yards to see how the optic and ammo performed. I used the Orange Peel Sight-In Target: 8-inch targets from Caldwell to group all the ammunition onto one target. I used the Thunder Beast Arms bipod and a Wiebad Fortune Cookiebag for stability to set the rifle up for bench shooting with each load. The best group was 0.51 inches with the Hornady Match 75-grain BTHP ammunition. The other loads shot under 1-inch or 1.5-inch groups at 50 yards with a red dot optic, which I was happy with.
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After zeroing and testing the accuracy of each load, TC and I loaded my Magpul D60 magazine with some 55-grain Super Vel ammunition for some fun plinking at the range. I used the ZemCo Designs D60 Band to keep the D60 lever always pinned down. This keeps the magazine safe from malfunctions, especially if I need to drop a somewhat full magazine onto the ground.
Final Thoughts
The Storm CAT 4 was hard to miss shots with. The gun is accurate, has little felt recoil thanks to the muzzle device, and was easy to get back on target with. We were shooting out to about 75 yards with the distance we had, but ringing steel supported off a Tank Trap and unsupported offhand as well. I want to mount a scope on the rifle next and see how far I can push it distance-wise.
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In a market flooded with AR-15s that all claim to do the same thing, the US PALM Storm CAT 4 actually manages to stand out. From the rock-solid Mono-Loc handguard system to the fully ambidextrous controls, upgraded Hiperfire trigger, and surprisingly effective Hurricane muzzle device, this rifle feels thoughtfully engineered rather than simply assembled from generic parts-bin components.
It shot flat, ran flawlessly, and delivered impressive accuracy even with a red dot optic mounted. Whether you’re looking for a dependable training rifle, a competition-ready setup, or just a premium AR that already includes the upgrades most shooters add later, the Storm CAT 4 checks a lot of boxes right out of the gate. After spending time behind the gun, it’s easy to see why US PALM is making noise with this release and honestly, this may be one of the best values currently available in the premium AR market.
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US PALM Storm CAT 4 Rifle Specifications
- Caliber: .223
- Barrel Length: 16 inches
- Twist Rate: 1:7
- Weight Unloaded: 7 pounds
- Trigger: Hiperfire EDT Designated Marksman Trigger
- Furniture: US PALM 7-Sided M-LOK Rail, US PALM Grip, Magpul DT Carbine Stock
- Overall Length (Collapsed): 33.5 inches
- Overall Length (Extended): 36.8 inches
- Overall Height: 7.3 inches
- Overall Width: 2.7 inches
- MSRP: $1,399.99
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