Colt ACR
- Category
- Assault Rifle
- Barrel
- 518 mm
- Weight, empty
- 3.31 kg
- Introduced
- 1989
About
What it is, and why it matters
The Colt ACR is an experimental assault rifle that served as Colt's entry in the United States Army's Advanced Combat Rifle (ACR) program of the late 1980s, an effort to find a successor capable of doubling the first-hit probability of the M16A2. Built on a modified M16A2 platform, it fired a duplex cartridge containing two stacked 5.56mm projectiles to increase hit probability at close range, and added an oil/spring hydraulic buffer that cut felt recoil by roughly 40 percent, a telescoping buttstock, a muzzle brake/compensator, and optics compatibility. The duplex round degraded long-range accuracy, so users still had to carry conventional M855 ball ammunition. None of the ACR contenders met the Army's requirements and the program was cancelled around 1990.
The Advanced Combat Rifle program sought a 100 percent improvement in hit probability over the M16A2. Four contractors reached Phase III (Colt, AAI, Steyr, and Heckler & Koch), but none of the radical approaches (duplex rounds, flechettes, caseless ammunition) proved worth the cost, and the program ended without a winner.
Designated M16A2E1 internally. The duplex round used two steel-cored copper-jacketed .224-inch projectiles (roughly 2.3 g front and 2.1 g rear) loaded nose-to-tail in a standard-length 5.56x45mm case. The rifle could also fire standard M855 5.56x45mm NATO ball.
Specification
Everything measured
IdentityWhat it is, who built it and when.
- Manufacturer
- Colt's Manufacturing Company LLC
- Category
- Assault Rifle
- Country
- United States
- Status
- Prototype
- Produced
- 1989 to 1990
DimensionsAs issued, without a magazine or an optic.
- Barrel
- 518 mm
- Overall length
- 1031 mm
- Weight, empty
- 3.31 kg
- Weight, loaded
- 4.67 kg
ActionHow it cycles, what trips it, and what feeds it.
- Action
- Gas operated
- Firing mechanism
- Hammer fired
- Trigger
- Single action
- 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
- Phosphate
BallisticsFrom the service cartridge, not a handload.
- Muzzle velocity
- 948 m/s
- Effective range
- 325 m
- Maximum range
- 548 m
- Rate of fire
- 650 rpm
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.
No load solved for this record yetThe flight path is computed from a cartridge and a bullet. This record has no ammunition filed against its chambering, so there is nothing to solve.
Features
What it has
What the record lists as fitted, drawn from the catalogue.
Telescoping buttstock
Hydraulic recoil buffer
Muzzle brake compensator
Optic mount
Oversized heat shield
Carrying handle
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 274 assault rifles | 3.31 kg | 3.59 kg | Lighter than about 70% |
| Overall lengthAmong 271 assault rifles | 1031 mm | 915 mm | Longer than about 90% |
| Barrel lengthAmong 271 assault rifles | 518 mm | 415 mm | Longer than about 90% |
| Magazine capacityAmong 276 assault rifles | 30 | 30 | Holds more rounds than about 60% |
Answers
Questions about the Colt ACR
How much does the Colt ACR weigh?
The Colt ACR weighs 3.31 kg (7.30 lb) empty and 4.67 kg (10.30 lb) loaded.
What caliber is the Colt ACR?
The Colt ACR is chambered in 5.56x45mm Duplex and 5.56x45mm NATO.
How many rounds does the Colt ACR hold?
The Colt ACR holds 30 rounds, fed from a detachable box magazine.
How long is the Colt ACR?
The Colt ACR is 1031 mm (40.6 in) long overall, with a 518 mm (20.4 in) barrel.
Who makes the Colt ACR?
The Colt ACR is made by Colt's Manufacturing Company LLC (United States). It was designed by Colt's Manufacturing Company.
When was the Colt ACR introduced?
The Colt ACR was introduced in 1989 and discontinued in 1990.
How does the Colt ACR operate?
The Colt ACR uses a gas operated 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 Army (trials only)
- 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/colt-acr' \ --header 'X-API-Key: your_key'{ "id": "colt-acr", "name": "Colt ACR", "manufacturer": { "id": "colt", "name": "Colt's Manufacturing Company LLC", "countryCode": "US", "foundedYear": 1855, "website": "https://www.colt.com", "logoUrl": null, "description": "American firearms manufacturer headquartered in Hartford, Connecticut. Founded in 1855 and now a subsidiary of Colt CZ Group, continuing production of iconic firearms including the 1911 pistol.", "status": "active", "defunctYear": null, "stateOwned": null, "makesFirearms": null, "parentId": null, "predecessorId": null, "createdAt": "2026-02-11 23:44:38", "updatedAt": "2026-02-18 03:43:38", "version": "7143c7ff3f7e156063a240f2df7b4746ee1c0394d7cd5f592d05bac43233d637" }, "category": { "id": "assault-rifle", "name": "Assault Rifle", "description": "Selective-fire rifles chambered in intermediate cartridges" }, "country_of_origin": "US", "year_introduced": 1989, "barrel_length_mm": 518, "weight_empty_g": 3310, "action_type": "gas_operated"}