An important part of any M4 build is the stock. This affects the firing of the weapon, your comfort and safety, and your accuracy, so finding the right stock for your carbine is no small matter.
Thankfully, we’ve got this guide to show you everything you need to know when it comes to M4 stocks, so read on to learn about the different types out there and five of the best M4 stocks on the market.
At a Glance: Our Top Picks for M4 Stock
- OUR TOP PICK: Magpul Industries Lightweight Carbine Stock
- BEST BUDGET OPTION: FAB Defense Stock
- BEST BENELLI OPTION: Mesa Tactical Urbino Pistol Grip Stock
Comparison Chart of the Best M4 Stocks
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How Does Brand Play a Role When It Comes to Stocks?
Brand plays a huge role when you're buying parts for a custom M4 build and this applies to stocks especially. They greatly impact the daily function and performance of your rifle and poorly-made stocks can lead to injury since a good durable product can change how recoil impacts your body.
Magpul Industries Lightweight Carbine Stock
Going with good brands that are known for quality is important in this day and age of internet marketplaces. It’s always a better idea to pay for quality instead of settling for some unknown brand that might have a stock made from cardboard. Always check reviews before purchasing too, as quality brands will likely have loyal customer followings that you can trust.
Types of M4 Stocks
There are several different kinds of M4 stocks to look at. These behave differently and can affect your experience with your firearm, so it’s imperative that you know how they differ from one another before you make any final decision.
Fixed
These stocks are completely immovable. They’re only usable in their first shape and length and are the most common kind of stock in the world. These might have carrying compartments for batteries or similarly-small cargo.
Collapsible/Folding
Collapsible stocks can get shortened or extended to modify their length. This can affect your firing stance or comfort. Folding stocks are what they’re called, as they can fold into smaller configurations for carrying or packing more easily.
Daniel Defense Collapsible Stock
Adjustable
These are shaped similarly to fixed stocks in that they might have a butt or cheek riser, but they can be adjusted with the length of those aspects as well as their overall length. Collapsible stocks can only be changed in length.
Minimalist/PDW
Finally, minimalist stocks are lightweight and small and are ideal for long trips to minimize your carrying weight. PDW (personal defense weapon), stocks are shorter and great for close-quarters tactical action. These also tend to be more durable than other types.
What Makes a Great M4 Stock?
Great M4 stocks have several qualities in common. So check the type and quality of each of these factors in any product you’re considering buying. These considerations will often impact the actual function of the device each time you fire your weapon.
Type
By far, the most important aspect is its type. Before you begin shopping, think about what kind of stock you’d like for your rifle. We went over the various types above, so it’s critical that you have your decision in mind and that you don’t get one that’s of the wrong type.
Length of Pull
This is how far the distance is between your rifle's trigger and the end of the buttstock. Too short of a LOP will mean your arm becomes cramped over time, while too long a LOP will affect your accuracy and prevent you from firing quickly at the right moment.
Mil-Spec or Commercial
Military-spec stocks are built to the same size as a traditional M4 carbine. This is only a difference of a small amount, usually less than a tenth of an inch when compared to commercial molds. This only really matters if you’re trying to get your rifle to be as close to a mil-issue model as possible.
Review of the Best M4 Stocks
Now that we’ve got all of our education out of the way, let’s have some fun! These are some of the best stocks on the market right now, and we’ll go through each one individually to show you how they shine in comparison to the others.
Best Overall:
Magpul Industries ACS-L Mil-Spec Carbine Stock
Pros
Cons
This stock is a great choice for most M4 builds due to its versatility and exceptional asking price. It’s affordable for anyone within a reasonable budget. This is a fixed model that fits onto most carbine receivers. It’s mil-spec, so it’s molded specifically to adhere to those sizing standards.
It has a large cheek at its end that adds some extra comfort when you rest it against your shoulder. This, along with the rubber butt pad, will negate a lot of the recoil you’ll feel when firing your carbine. However, this butt pad is replaceable and isn’t the longest-lasting piece of the stock, as heat and general wear and tear will eventually require you to get a new one.
That being said, while it works, it’s very comfortable and is of a great size for most shooters, measuring in at about eight inches in length. It’s really easy to install on your build and uses a chrome-silicon lock spring to latch everything securely.
Bottom Line
This is a versatile, comfortable offering that has a wide cheek for added comfort and stability. The butt pads are replaceable and don’t last forever, but they offer extreme comfort while they’re in their prime.
Best for the Money:
FAB Defense M4 Stock with Adjustable Cheek Riser
Pros
Cons
This is a stock that works equally well for both left and right-handed users: something of a rarity in the gun market. It has a quick-detach ring connector so that no matter your dominant hand, you’ll be able to remove, replace, or adjust it in seconds.
Since it’s an adjustable model, it allows you to modify the cheek riser to better acclimate to your personal level of comfort and your individual shooting stance. The butt is wide enough to be comfortable for most shoulders and features a textured traction end that will reduce slippage, much like the patterns underneath anti-slip boots.
There’s also a storage compartment included that’s perfect for storing batteries for your rifle’s scope. This item is a bit busy in terms of design and function, but that’s a very small flaw when the rest of the product is really excellent in terms of value for money.
Bottom Line
The stock is adjustable with its cheek riser, made from sturdy materials and has a battery compartment for a rifle’s scope. The butt has an anti-slip rubber ending and an ambidextrous quick-detach connector, making this great for left-handed shooters.
Best Benelli Option:
Mesa Tactical Urbino Pistol Grip Stock
Pros
Cons
This is definitely an option if you’re after a custom build that doesn’t follow strict mil-spec standards. The Mesa Tactical Urbino stock is made from a pistol mold that’s commonly seen on shotguns and other high-impact weapons.
Why would you want this on your M4? Depending on your ammunition, you might be firing rounds that have a tendency to wear out your shoulder. This absorbs recoil very effectively and can preserve your shooting time by keeping your time firing comfortable and manageable. It’s very durable and can withstand shock and impact from all but the heaviest types of shells.
It's very easy to shoulder, isn't likely to slip, and it's made from glass-filled nylon to promote excellent shape retention even as years pass. It has a pretty long LOP at 12.5 inches, so if you have shorter arms or aren’t wearing body armor you might want to move on to something else. However, if you qualify for either of those two conditions this is an excellent choice.
Bottom Line
This pistol grip stock was originally made for shotgun use, so it’ll be great at managing the lesser recoil from an M4. It’s anti-slip, easy to shoulder and made from special nylon that’s designed to last for quite a long time. It does have a very long LOP, so take note.
Best Mil-Spec Option:
Daniel Defense AR-15 Collapsible Stock
Pros
Cons
This is a collapsible stock model that provides a really quick response if you need to pack up and move from location to location quickly. For that reason, it excels on lighter M4 builds that are going to be used for long-term scouting exercises or games to be played where a lot of movement is key.
It is comfortable and has a soft rubber cheek weld for easy sighting and reduced recoil even if you fire from right next to your face. It’s rather small and compact even before it collapses, and engaging the collapsing function is smooth and responsive every time. Rotation sockets on either side allow you to attack slings very quickly as well.
There isn't a storage compartment or any interesting extra features, but for the asking price, you can get a dependable, collapsible stock that's perfect for any build that relies on that function. It's also mil-spec if you care about making an M4 that's as close to the military shape and style as possible.
Bottom Line
This is a lightweight, small collapsible stock that doesn’t have a storage slot or any flashy features. It’s dependable, reliable, and collapses consistently and with speed every time. This makes it a great choice if your number one question for a stock is “Can it collapse?”.
Best Magpul Option:
Magpul Industries MOE M4 Carbine Stock
Pros
Cons
Here we have a stock whose storage compartment is easy to see. It’s very spacious when compared to competitor stocks and is waterproof, to boot. This means you can safely store batteries or small electronics inside without worrying about them becoming damaged, even if you have to submerge your rifle in water.
This item is lightweight and slim on either side, making it a compact example of an adjustable stock. It’s got a maximum range of over seven inches and can be adjusted within 3.3 inches, allowing for some good variation for shooters of most arm lengths.
This product is also very comfortable to use and sports sling swivels on either side of its base for use with individuals who are left or right-handed. The butt has a rubber pad added to it that’s optimized for body armor use and the rolled toe stops slipping even during phases of rapid fire.
Bottom Line
This storage stock can be adjusted within a few inches and has a compartment that’s totally waterproof. This is a great versatile option that’s perfect for outdoor or tactical situations, and its sleek design will look great on some custom M4 carbines.
Best M4 Collapsible Option:
Magpul Industries UBR Gen2 Collapsible Stock
Pros
Cons
Finally, this is one of the pinnacles of adjustable stock examples due to its unique system of preset LOP ranges. There are eight different settings you can choose from for your perfect LOP, so it’ll be a great choice for shooters of varying arm lengths. Because of this customizability, you can even hand the weapon from man to man and trust that they'll be able to find a LOP that's acceptable for their comfort.
The butt pad is also designed for comfort, given that it has a rubber end that’s covered in tread to reduce slipping on clothing or body armor. The storage compartment is located there and has a reversible door depending on your preference.
The entire device is made from multiple shells to withstand recoil and shock impact and preserve the lifespan of the unit. It’s a very steady, solid stock despite its adjustability, even matching truly fixed stocks in terms of stability. You won't experience any rattling when using this.
Bottom Line
This is a phenomenal example of an adjustable stock that pulls out all the stops. It has a storage compartment like a fixed stock and enough stability to go toe-to-toe with the steadiest models out there, along with an anti-slip butt and a comfortable rubber ending that's perfect for unarmored or armored shooters. The eight different adjustment selections help you find the perfect setting for your individual arm length.
Conclusion
With our guide and the great stocks we’ve reviewed, you’re well on your way to finishing your M4 build and showcasing your completed rifle to your buddies! No matter what your favorite kind of stock is, we’re sure there’s a great option for you out there.
