# CMMG Banshee MK57: Tactical 5.7mm Handgun, 20-Round Capacity

**Brand:** CMMG
**Category:** Pistol Caliber Carbines
**Caliber:** 5.7x28mm

## Specifications

- **Caliber:** 5.7x28mm
- **Barrel Length:** 8"
- **Capacity:** 20 rounds
- **Weight:** 76.8 oz
- **UPC:** 810148624446
- **SKU:** UCEGJR45W

## Description

The CMMG Banshee MK57 is a semi-automatic pistol chambered in 5.7x28mm, built around CMMG's radial delayed blowback operating system. That mechanism keeps felt recoil low for the caliber and contributes to the gun's reputation for reliable cycling across a range of loads.

### Key Specifications
- **Model:** Banshee MK57
- **Manufacturer:** CMMG
- **Type:** Semi Auto Handgun - Tactical
- **Caliber:** 5.7 x 28mm
- **Barrel Length:** 8 inches
- **Capacity:** 20 rounds (ProMag)
- **Weight:** 4.8 lbs
- **Length:** 23.7 inches
- **Operating System:** Radial Delayed Blowback

### Detailed Features
The upper receiver is billet 6061 T6 aluminum. The ambidextrous charging handle works for left- or right-handed shooters without modification. A CMMG ZEROED linear compensator is included, which directs muzzle blast forward rather than to the sides, useful when shooting in confined bays or next to other shooters.

The 5.7x28mm round is high-velocity and relatively flat-shooting, which appeals to shooters who want those ballistic characteristics in a pistol-format package. The 20-round ProMag gives meaningful capacity without requiring a magazine swap mid-string.

### Usage
The Banshee MK57 fits tactical shooting sports, range use, and home defense. At 4.8 lbs and 23.7 inches it is not a pocket carry option, but that size allows the 8-inch barrel to extract more velocity from the 5.7mm round than shorter barrels would. Ammunition cost and availability are real factors to consider with this caliber. 5.7x28mm is less common than 9mm and tends to cost more per round.

## What Reviewers Say

*Quoted verbatim from YouTube reviews. Each link opens the video at the moment quoted.*

> There can be a lot more violent action coming back and give you that recoil but it helps to mitigate it with that delay in the bolt and so it just makes it a real pleasure to shoot.
>
> — [sootch00](https://www.youtube.com/watch?v=St_mfytrgxk&t=555s)

> This hand guard is super comfortable with the c clamp style grip i usually install these vendetta precision hand stops on all my hand guards except i don't feel like i need it here.
>
> — [bench175](https://www.youtube.com/watch?v=kweJmostLzA&t=123s)

> Man it just really had tight groups this is really a great rifle.
>
> — [sootch00](https://www.youtube.com/watch?v=St_mfytrgxk&t=638s)

> One of the great things about the caliber and especially in this configuration is that it is just such a joy to shoot.
>
> — [sootch00](https://www.youtube.com/watch?v=St_mfytrgxk&t=876s)

> When it came to the 30 round magazines from pro mag we did have a few issues.
>
> — [sootch00](https://www.youtube.com/watch?v=St_mfytrgxk&t=575s)

## What Customers Say

*AI-generated insights from customer reviews*

5.7mm fans tend to be enthusiastic about the Banshee MK57. The compact form factor, low recoil, and 20-round capacity get consistent praise. The Cerakote finish also gets positive mentions for appearance.

The main friction points are ammunition cost and supply. 5.7x28mm is harder to find and more expensive than mainstream pistol calibers, which affects how often some owners actually shoot it. A few users also note the price of the pistol itself is on the high side relative to 9mm alternatives with similar capacity.

Aftermarket support is growing but limited compared to more established platforms. Shooters who want to customize tend to watch forums closely for compatible parts. Overall the reception is positive among those who specifically want 5.7mm. The question most buyers work through is whether the caliber tradeoffs fit their use case.

## Pricing

**2 offers available**

| Vendor | Price |
|--------|-------|
| Classicfirearms Com | $1552.85 |
| Buds Gun Shop | $1589.99 |

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*Data from [GunsNation](https://gunsnation.com)*