# Sig Sauer M400 Sentry 5.56 NATO 16in

**Brand:** SIG Sauer
**Category:** AR Style Rifles
**Caliber:** 5.56 NATO

## Specifications

- **Caliber:** 5.56 NATO
- **Barrel Length:** 16"
- **UPC:** 798681716128
- **SKU:** UCE3nP5PM

## Description

The Sig Sauer M400 Sentry is an AR-pattern semi-automatic rifle chambered in 5.56 NATO (.223 Rem). It has a 16-inch barrel and ships as a package with a ROMEO 5 Gen II red dot sight and a Foxtrot MSR light. The magazine capacity is 30+1 rounds.

### Key Specifications
- **Brand**: Sig Sauer
- **Model**: M400 Sentry
- **Caliber**: 5.56 NATO
- **Action**: Semi Auto
- **Capacity**: 30+1
- **Barrel Length**: 16 in

### Detailed Features
- AR-pattern semi-automatic rifle chambered in 5.56 NATO
- 16-inch barrel
- Package includes ROMEO 5 Gen II red dot sight
- Package includes Foxtrot MSR light
- 30-round magazine included

## Frequently Asked Questions

**Q: What caliber is the M400 Sentry?**

A: The Sig Sauer M400 Sentry is chambered in 5.56 NATO (.223 Rem).

**Q: Who makes the M400 Sentry?**

A: The M400 Sentry is made by Sig Sauer.

**Q: What type of firearm is the M400 Sentry?**

A: The M400 Sentry is an AR-pattern semi-automatic rifle.

**Q: What is the barrel length of the M400 Sentry?**

A: It has a 16-inch barrel.

**Q: How many rounds does the M400 Sentry hold?**

A: It has a 30+1 capacity and ships with a 30-round magazine.

**Q: What accessories are included with the M400 Sentry?**

A: The package includes a ROMEO 5 Gen II red dot sight and a Foxtrot MSR light.

**Q: Where can I buy the M400 Sentry?**

A: Compare current vendor offers on this page.

## What Customers Say

*AI-generated insights from customer reviews*

Owners of the M400 Sentry package appreciate getting a functional optic and light bundled with the rifle rather than assembling the kit separately. The ROMEO 5 Gen II is well-regarded for durability and clarity at its price tier, and the Foxtrot MSR light adds practical utility. The 5.56 NATO chambering keeps the platform compatible with common ammunition.

The M400 is Sig's AR-pattern gas-operated rifle, and most owners report solid reliability out of the box. The 16-inch barrel gives a balanced length for both field use and storage. The trigger feel on the base configuration draws some criticism for a heavier pull than aftermarket options, but it functions without issues.

The Sentry package is often compared to building a comparable setup from individual components. Most buyers find the bundled price reasonable when the sight and light are factored in. Owners who prefer a different optic sometimes see less value in the package, but for those who like the ROMEO 5 Gen II pairing, it represents a practical starting point.

## Pricing

**12 offers available**

| Vendor | Price |
|--------|-------|
| Brownells | $1749.99 |
| Guns Com | $1749.99 |
| Kygunco Com | $1749.99 |
| Classicfirearms Com | $1749.99 |
| Buds Gun Shop | $1749.99 |
| Impactguns Com | $1749.99 |
| Grabagun Com | $1749.99 |
| Shootingsurplus Com | $1749.99 |
| Selwayarmory Com | $1749.99 |
| Globalordnance Com | $1749.99 |

*...and 2 more offers*

## Similar Products

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- [Sig Sauer M400 5.56 NATO 16in Black](https://gunsnation.com/p/sig-sauer-m400-5-56-nato-16in-black/UCE3nOpT7)
- [Sig Sauer M400 Tread 5.56 NATO 16in Black](https://gunsnation.com/p/sig-sauer-m400-tread-5-56-nato-16in-black/UCE3nP5Bi)
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*Data from [GunsNation](https://gunsnation.com)*