Description
The CIA HG00010001AA-N US PALM CAT4 556 PSTL 11.5 is a purpose-built 5.56 NATO pistol that brings the reliability of a short-stroke gas piston system to a compact, maneuverable platform. Chambered in 5.56 NATO and built on an 80% lower receiver, this pistol offers shooters a lightweight, accurate option for home defense, truck gun, or range use. At $1,299.99, it delivers proven US Palm engineering and a durable finish that holds up to hard use.
| Manufacturer | US Palm (CIA) |
|---|---|
| Model | CAT4 556 PSTL 11.5 |
| Material | 7075-T6 aluminum upper and lower receiver (per manufacturer specs) |
| Compatibility | 5.56 NATO / .223 Remington magazines |
| Finish | Type III hard coat anodized black |
| Weight | 5.8 lbs (unloaded, per manufacturer specs) |
| Condition | New |
Key Features
- Short-Stroke Gas Piston System — Why it matters: Keeps the action clean and reliable, especially when running suppressed or with lower-quality ammunition, reducing fouling in the bolt carrier group.
- 11.5-Inch Barrel with 1:7 Twist — Why it matters: Stabilizes both light 55-grain and heavy 77-grain projectiles, giving you accuracy out to 300 yards while keeping the overall length short for close-quarters use.
- US Palm Enhanced Bolt Carrier — Why it matters: Features a nickel-boron coated carrier that reduces friction and makes cleaning easier, so you spend less time scrubbing and more time shooting.
- Free-Float M-Lok Handguard — Why it matters: Provides a rock-solid mounting platform for lights, lasers, and grips without affecting barrel harmonics, improving accuracy.
- Adjustable Gas Block — Why it matters: Lets you tune the gas system for suppressed or unsuppressed use, reducing felt recoil and minimizing wear on internal parts.
Who It’s For
This pistol is built for shooters who want a compact 5.56 platform without sacrificing reliability. It’s ideal for home defense because the 11.5-inch barrel keeps it short enough to maneuver in tight spaces, but long enough to maintain good velocity. It’s also a solid choice for truck guns, range toys, or anyone who wants a lightweight pistol that runs on common AR-15 magazines. New gun owners will appreciate the piston system’s cleaner operation and less frequent cleaning schedule.
Pros & Cons
- Pro: Piston system runs cleaner than direct impingement, especially with a suppressor.
- Pro: 11.5-inch barrel offers a good balance of ballistics and portability.
- Pro: Adjustable gas block lets you tune for different loads and suppressors.
- Con: The 80% lower receiver requires finishing (drilling and milling) before assembly, which adds time and requires some DIY skill or a gunsmith.
- Con: Slightly heavier than a comparable direct-impingement pistol due to the piston system components.
Comparison vs. Competitors
| Feature | CIA US PALM CAT4 556 PSTL 11.5 | Zev Technologies OZ9C | Agency Arms AOM-9 |
|---|---|---|---|
| Caliber | 5.56 NATO | 9mm | 9mm |
| Barrel Length | 11.5 inches | 4.0 inches | 4.6 inches |
| Operating System | Short-stroke gas piston | Direct impingement | Direct impingement |
| Weight (unloaded) | 5.8 lbs | 1.9 lbs | 2.1 lbs |
| Lower Receiver | 80% (requires finishing) | Complete serialized | Complete serialized |
| Price | $1,299.99 | $1,699.99 | $1,899.99 |
Does this pistol come with a brace or stock?
No, the CIA HG00010001AA-N ships as a pistol without a brace or stock. It is configured with a buffer tube and pistol-length receiver extension. You can add a pistol brace if desired, but check local regulations first.
Can I use standard AR-15 magazines?
Yes, it accepts all standard AR-15 pattern magazines in 5.56 NATO/.223 Remington, including Magpul, Lancer, and GI-style magazines. It is not compatible with 9mm or other caliber magazines.
Do I need to finish the 80% lower myself?
Yes, the 80% lower receiver requires drilling and milling the fire control pocket and trigger pin holes. If you’re not comfortable with DIY gunsmithing, any local gunsmith can finish it for you. The pistol does not include a completed lower.
Is this pistol California legal?
No, this pistol is not on the California approved handgun roster and does not meet California’s assault weapons laws due to its magazine outside the pistol grip and threaded barrel. It is not for sale to California residents.
What is the warranty on this pistol?
US Palm offers a limited lifetime warranty against manufacturing defects. This covers the upper receiver, barrel, and bolt carrier group. Wear items like springs and extractors are covered for one year.
✅ Nationwide delivery (all 50 states)
✅ Ships 1-2 business days
✅ 30-day returns
✅ Secure checkout
Semi Auto Handguns | AR Pistols | 80% Lower Receivers
Last updated: April 2026
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