Mk4 T
- Category
- Carbine
- Barrel
- 406 mm
- Weight, empty
- 2.86 kg
- Introduced
- 2014
About
What it is, and why it matters
The CMMG Mk4 T is a value-oriented AR-15 style semi-automatic rifle chambered in 5.56x45mm NATO, introduced in 2014 as part of CMMG's Mk4 platform expansion. Manufactured by CMMG Inc. in Boonville, Missouri, the Mk4 T emphasizes affordability and reliability without sacrificing essential features. The rifle features a 16-inch medium-weight tapered barrel, forged 7075-T6 aluminum M4 upper and AR-15 lower receivers, and an RKM11 KeyMod free-floating handguard with top-mounted Picatinny rail. KeyMod attachment points at 3, 6, and 9 o'clock positions provide a lightweight, low-profile alternative to full-length Picatinny rails. Standard furniture includes an A2 pistol grip and M4 buttstock with 6-position mil-spec receiver extension. Weighing just 6.3 pounds unloaded and measuring 32 inches with stock collapsed, the Mk4 T offers excellent maneuverability. CMMG's single-stage mil-spec trigger provides consistent performance, while the forged receivers ensure durability. The Mk4 T represents CMMG's mission to provide quality AR-15s at accessible price points for law enforcement, competitive shooters, and recreational users.
Born in the heart of Missouri by a family-run operation, the CMMG Mk4 T represents the American firearms industry's grassroots spirit-no government contracts, no military heritage, just the Overstreet family's commitment to building affordable, reliable AR-15s that everyday shooters could trust. When CMMG announced the Mk4 T in 2014, they weren't trying to revolutionize the AR-15; they were simply proving that quality didn't have to come with a premium price tag.
CMMG Inc. was founded in 2002 in Fayette, Missouri, by John, Jeff, Gretchen, and Stephanie Overstreet, initially focusing on AR-15 lower receivers. The company name stands for 'Central Missouri Machine Guns.' In 2016, CMMG relocated to a larger facility in Boonville, Missouri (the Overstreet brothers' childhood home), to address growth constraints. The Mk4 platform designation indicates CMMG's AR-15 format rifles, distinguishing them from the larger Mk3 (AR-10 format) and smaller Mk9/Mk10 (pistol-caliber) platforms. The 'T' designation in Mk4 T likely indicates 'Tactical,' though CMMG has not officially clarified this. The Mk4 T's 1:9 twist rate is optimized for 55-62 grain ammunition, making it suitable for training and recreational shooting with standard .223/5.56 loads. CMMG offers the Mk4 T in multiple calibers including .300 AAC Blackout, 9mm, and .22 Long Rifle, utilizing the same core platform with caliber-specific modifications. KeyMod attachment system predates M-LOK and offers similar benefits-reduced weight compared to full Picatinny rails while maintaining accessory mounting capability. The Mk4 T competes directly with budget-friendly offerings from Smith & Wesson, Ruger, and Palmetto State Armory, emphasizing value and American manufacturing. CMMG's dedication to customer service and quality control has earned strong reputation despite lower brand recognition compared to major manufacturers.
Specification
Everything measured
IdentityWhat it is, who built it and when.
- Manufacturer
- CMMG Inc.
- Category
- Carbine
- Country
- United States
- Status
- In production
- Produced
- 2014
DimensionsAs issued, without a magazine or an optic.
- Barrel
- 406 mm
- Overall length
- 813 mm
- Weight, empty
- 2.86 kg
- Weight, loaded
- 3.30 kg
ActionHow it cycles, what trips it, and what feeds it.
- Action
- Gas operated direct impingement
- Firing mechanism
- Hammer fired
- Trigger
- Single stage
- Trigger pull
- 32.0 N
- Capacity
- 30
- Magazine
- Detachable box
MaterialsEach swatch is the material itself, not a colour chosen to stand for it.
- Frame
- Aluminum alloy
- Barrel
- Steel
- Stock
- Polymer
- Finish
- Hard anodized
BallisticsFrom the service cartridge, not a handload.
- Muzzle velocity
- 905 m/s
- Muzzle energy
- 1640 J
- Effective range
- 500 m
- Maximum range
- 3600 m
Trajectory
What the round does downrange
Solved from the muzzle figures and the bullet. The dashed rule is the effective range on the record, and the crosses are the steps the solver returned.
Features
What it has
What the record lists as fitted, drawn from the catalogue.
Free float handguard
Keymod mounting
Medium weight barrel
Collapsible stock
Accessory rail
Forward assist
Dust cover
Flat top receiver
Picatinny rail
A2 pistol grip
M4 stock
Standing
How it compares
Each figure against the firearms of the same type and cartridge that record it, or of the same type where that cartridge has too few. Positions are read to the nearest tenth.
| Measurement | This firearm | Median | Position |
|---|---|---|---|
| Empty weightAmong 141 5.56x45mm NATO carbines | 2.86 kg | 2.95 kg | Lighter than about 70% |
| Overall lengthAmong 144 5.56x45mm NATO carbines | 813 mm | 838 mm | Shorter than about 70% |
| Barrel lengthAmong 150 5.56x45mm NATO carbines | 406 mm | 406 mm | Longer than about 70% |
| Magazine capacityAmong 150 5.56x45mm NATO carbines | 30 | 30 | Near the median |
Answers
Questions about the Mk4 T
How much does the Mk4 T weigh?
The Mk4 T weighs 2.86 kg (6.30 lb) empty and 3.30 kg (7.27 lb) loaded.
What caliber is the Mk4 T?
The Mk4 T is chambered in 5.56x45mm NATO.
How many rounds does the Mk4 T hold?
The Mk4 T holds 30 rounds, fed from a detachable box magazine.
How long is the Mk4 T?
The Mk4 T is 813 mm (32.0 in) long overall, with a 406 mm (16.0 in) barrel.
Who makes the Mk4 T?
The Mk4 T is made by CMMG Inc. (United States). It was designed by Eugene Stoner.
When was the Mk4 T introduced?
The Mk4 T was introduced in 2014.
How does the Mk4 T operate?
The Mk4 T uses a gas operated direct impingement action, and its firing mechanism is hammer fired.
Compatibility
Which parts fit this firearm
Studio
Every part that mounts on this, resolved
Not a list the maker typed out: the answer comes from the mounts this firearm exposes and the interface each part needs, so it stays right when either one changes.
- Every part that mounts on any firearm in the catalogue
- Interface standards, platforms and fit overrides
- The same answers through the API and the MCP server
Requires a signed-in GunSpec account on the Studio plan. The answer is computed per part, so it is not part of the public record.
Provenance
What the record holds
Every figure above was taken from one of these pages. The confidence reflects how much of the record came from a page a claim can be checked against.
In service
- United States Law Enforcement
- United States
- Civilian Sport Shooters
- United States
Provenance
Confidence in this record
82%
Stockists
Where to buy
Offers link straight to the shop. GunSpec never takes the order.
No shop has listed this firearm yet
Stock and prices come from the shops themselves. If you sell this firearm, you can list it and it appears here.
List a firearmMCP
Ask an assistant about it
The same record, reached the way a person asks for it rather than the way a program does.
Ask GunSpec
Works with
Point an MCP client at GunSpec and it answers from the catalogue rather than from memory. A free key covers the read tools.
API
The call that returns this record
The same fields, in the same units, from the same endpoint the page reads.
curl --request GET \ --url 'https://api.gunspec.io/v1/firearms/cmmg-mk4-t' \ --header 'X-API-Key: your_key'{ "id": "cmmg-mk4-t", "name": "Mk4 T", "manufacturer": { "id": "cmmg", "name": "CMMG Inc.", "countryCode": "US", "foundedYear": 2002, "website": "https://cmmg.com", "logoUrl": null, "description": null, "status": null, "defunctYear": null, "stateOwned": null, "makesFirearms": null, "parentId": null, "predecessorId": null, "createdAt": "2026-02-11 23:44:38", "updatedAt": "2026-02-18 03:43:43", "version": "a7e68de40df3e6e52ce7309f32c551e46f69ca644a4955a2de5291d2bfbf7a0b" }, "category": { "id": "carbine", "name": "Carbine", "description": "Shortened rifles for close-quarters use" }, "country_of_origin": "US", "year_introduced": 2014, "barrel_length_mm": 406, "weight_empty_g": 2858, "action_type": "gas_operated_direct_impingement"}