Brownells M4 Adjustable Buttstock, Black

The Brownells M4 Adjustable Buttstock is a field-proven, mil-spec stock built for AR-15 platform rifles. If you're running a direct impingement system or looking to upgrade from a fixed stock, this ribbed-profile design delivers the comfort of length-of-pull adjustment without the weight or complexity of proprietary systems. It's the same platform trusted by military armorers and OEM manufacturers, so you know it's engineered for real-world use—whether you're setting up a rifle for precision shooting, hunting, or duty applications.

Adjustable stocks solve real problems: they accommodate different body types, gear setups, and shooting positions. Dial in the length that works for your frame and your hunting jacket or plate carrier, and the ribbed design provides a secure, non-slip surface when you're shouldering the rifle. The included sling swivel gives you a solid attachment point for a two-point sling, which matters whether you're hiking to a stand or moving through a training course.

Installation is straightforward if you already have a mil-spec buffer tube in place. This stock seats directly onto standard AR-15 receiver extensions—no adapters needed. If you're building a rifle from scratch or replacing a damaged stock, confirm your buffer tube is mil-spec compatible before ordering. The Brownells M4 is the no-nonsense choice when you want proven design without the markup of branded alternatives.

Key Features

• Adjustable length of pull for rifle fit and comfort
• Ribbed profile for secure, non-slip shouldering
• Mil-spec compatible with standard AR-15 buffer tubes
• Sling swivel attachment point included
• Military-grade design proven in field use

Specifications

Frequently Asked Questions

Will this fit my AR-15?

The Brownells M4 Adjustable Buttstock is designed for AR-15 rifles with a mil-spec buffer tube. If your rifle uses a standard AR-15 receiver extension (most do), this stock will fit. If you're unsure, check your current stock or buffer tube—mil-spec is the industry standard. The stock itself is not included, so you'll need that component already in place.

What's included with this stock?

The Brownells M4 comes with a sling swivel for quick attachment of a two-point sling. The buffer tube is not included; you'll need a mil-spec buffer tube already installed on your rifle.

Can I adjust the length of pull?

Yes. The M4 features multiple adjustment positions so you can dial in a length that works for your body size and the gear you're running. This is especially useful if you shoot with body armor or heavy outerwear, or if you want a shorter pull for close-quarters setups.

What makes this stock suitable for hunting?

The adjustable length of pull lets you find the right fit whether you're in a t-shirt or bundled for cold-weather hunting. The ribbed design grips your shoulder solidly, and the included sling swivel makes it easy to set up a carry system for your rifle when you're glassing terrain or moving between positions.