The CMMG Banshee MK4 5.7x28mm 5″ 40+1 is a compact AR-style pistol built for home defense, range training, and family shooting. It combines a 5-inch barrel with a 40+1 round capacity, giving you a lightweight, low-recoil platform that is easy for shooters of all ages to handle.
| Manufacturer | CMMG |
|---|---|
| Model | Banshee MK4 |
| Material | 7075-T6 aluminum upper and lower receiver (per manufacturer specs) |
| Compatibility | Standard AR15 lower receiver, CMMG AR conversion magazines |
| Finish | Hardcoat anodized black |
| Weight | 5.5 lbs (unloaded, per manufacturer specs) |
| Condition | New |
Key Features
- Ultra-Compact Barrel – The 5-inch barrel keeps overall length to just 18.5 inches, making this pistol easy to maneuver in tight spaces like hallways or vehicles. Why it matters: You get a full-power 5.7x28mm round in a package that fits in a small safe or range bag.
- High-Capacity 40+1 Magazine – Standard 40-round magazine with one in the chamber gives you 41 rounds on tap. Why it matters: Fewer reloads mean more time focusing on your target, especially for newer shooters.
- EML4 M-LOK Handguard – Slots at 3, 6, and 9 o’clock plus a full-length Picatinny top rail let you mount lights, lasers, or grips. Integrated handstop keeps your support hand safe. Why it matters: You can customize the pistol to fit your family’s needs without extra purchases.
- Ambidextrous Safety – Left- and right-side safety lever makes the pistol usable by both left- and right-handed shooters. Why it matters: Teaching a family member with a different dominant hand is simpler when the controls work for everyone.
- CMMG Zeroed Grips – Ergonomic grip texture provides a secure hold, even with sweaty hands or gloves. Why it matters: A confident grip improves accuracy and safety for beginners.
Who It’s For
This pistol is designed for families, youth shooters, and beginners who want a reliable, low-recoil platform for home defense or range practice. The 5.7x28mm cartridge produces less felt recoil than 9mm or .223, making it easier for smaller shooters to control. The compact size also suits shooters with shorter arms or those who prefer a lightweight firearm.
Pros and Cons
- Pros: Low recoil, 40+1 capacity, ambidextrous controls, integrated handstop, compact size for storage.
- Cons: Ammunition cost is higher than 9mm, and the 5-inch barrel reduces muzzle velocity compared to longer barrels. This is a trade-off for the short length.
Comparison
| Feature | CMMG Banshee MK4 5.7x28mm | Zev Technologies OZ9C | Geissele Super Duty Pistol |
|---|---|---|---|
| Caliber | 5.7x28mm | 9mm | 5.56 NATO |
| Barrel Length | 5 inches | 4.5 inches | 11.5 inches |
| Capacity | 40+1 | 15+1 | 30+1 |
| Weight (unloaded) | 5.5 lbs | 1.9 lbs | 5.9 lbs |
| Recoil | Low | Moderate | Moderate |
| Price | $1,586.31 | $1,899.00 | $1,749.00 |
FAQ
Is the CMMG Banshee MK4 5.7x28mm legal to own?
Yes, this is a pistol with a brace (not a stock) and a barrel under 16 inches, so it is classified as a pistol under federal law. You must be 21 or older to purchase from a licensed dealer. Check your state and local laws for any restrictions on pistol braces or magazine capacity.
What magazines does this use?
It uses CMMG AR conversion magazines designed for 5.7x28mm. These are 40-round magazines with a steel body and polymer follower. They are compatible with standard AR15 lower receivers.
Can I add a suppressor to this pistol?
Yes, the barrel is threaded 1/2×28, which is standard for 5.7x28mm suppressors. You will need to verify that the suppressor you choose is rated for the cartridge and that your local laws allow suppressor ownership.
Is this suitable for a beginner shooter?
Yes. The low recoil of 5.7x28mm, combined with the ambidextrous safety and integrated handstop, makes it a good choice for new shooters. We recommend starting with basic safety training and supervised practice.
What is the warranty on this pistol?
CMMG offers a limited lifetime warranty to the original owner. For full details, visit the CMMG website or contact their customer service.
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Last updated: April 2026
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