Robinson Armament XCR
2004 Prototype CQB/SBR version of XCR
Type	Automatic / Semi-automatic rifle
Place of origin	United States
Production history
Designer	Alex J. Robinson
Designed	2004
Manufacturer	Robinson Armament Co.
Produced	2006–Present
Variants	XCR-L, XCR-PDW, XCR-M, XCR-Micro
Specifications
Weight	7.5 lbs
Length	37.75" (Stock Extended); 27.4" (Stock Folded)
Barrel length	16" standard 12" CQB model 18" HBAR SPR 9" PDW model 7.5" Micro/Pistol
Caliber	5.56x45mm NATO, 7.62x39mm, 6.8 mm SPC, 6.5 mm Grendel, any other calibers that will fit a 5.56 mm envelope
Action	Gas-operated Kalashnikov type long-stroke piston/ Rotating bolt
Rate of fire	700-900 rounds/min
Muzzle velocity	792-990 m/s (2600-3250 ft/s)
Effective range	300-600 m (328-656 yd), depending on configuration
Feed system	30-round detachable box (5.56 variant) magazine, staggered-column magazine (STANAG compatible)
Sights	(Picatinny rail)

The Robinson Armament Co. XCR is a multi-caliber, gas piston weapon system developed by Robinson Armament Co. for U.S. Special Operations Command (SOCOM) to satisfy the requirements of the SOF Combat Assault Rifle^[1], or SCAR competition, but was disqualified on a technicality due to late delivery of blank firing adapters. Robinson Armament continued development and the XCR is now being offered to law enforcement, the military and general public. Deliveries of the rifle began in mid-2006. The XCR displayed to U.S. Army officials during an invitation-only Industry Day on November 13, 2008. The goal of the Industry Day was to review current carbine technology prior to writing formal requirements for a future replacement for the M4 Carbine.^[2][3]

Overview

The XCR utilizes a heavy duty bolt and extractor connected to an AK-47 type gas piston. The bolt and extractor are designed and patented by Robinson Arms, and promoted as offering higher performance over eight lug M16/M4 type bolts. Other features include a folding stock which eases storage space consumption and deploying from a vehicle, in addition to folding M4 Carbine style stocks for those who prefer length of pull adjustments; it also has a monolithic top Picatinny rail with side and under-barrel rails, and forward assist integrated into left-side charging handle. Approximately 5,000 XCR carbines have been sold since its introduction in 2006.

Caliber Conversions

The XCR is a multi-caliber weapon system. The base platform is chambered in 5.56x45 NATO. Conversions to other calibers and barrel lengths can be performed in 2 to 3 minutes without the need of a trained armored using a standard hex wrench, and consist of changing to the appropriately chambered barrel and bolt, replacing brass deflector (optional) and insertion of appropriate magazine. 6.8 Remington SPC and 7.62x39 are the current conversion kits available. 6.5 Grendel was scheduled for future release, but is currently on hold due to technical hurdles
In addition to conversion kits, complete factory guns in the alternate calibers are also sold.

Operating Mechanism

The XCR employs a Kalashnikov type, gas operated action with the bolt carrier attached to a long-stroke gas piston; the gas chamber is located above the barrel.
The proprietary bolt is a three-lug design that locks onto the barrel extension leaving the upper receiver unstressed. There is no need to check the headspace when changing barrels. A steel fixed ejector is attached to the inside of the receiver, held in place by two bolts. The manufacturer claims this design provides stronger ejection than what is offered on the AR-15’s spring loaded ejector design. The ejection pattern is to the two o'clock position of the operator, with an optimum distance of 15ft to 20ft depending on ammunition type and gas setting.^[4]
Magazines are STANAG 4179 type.

Upper and Lower Receiver

The upper receiver is made from anodized aluminum forgings, and is non-stressed. It features a non-reciprocating charging handle on left side which also acts as a forward assist.
The quad rail system is integrated into the upper receiver and compatible with most 1913 Picatinny devices. The top rail is monolithic and 17” long, providing a rigid, uninterrupted plane for mounting optics and BUIS (Backup Iron Sights); the 3, 6, and 9 O'clock Position Rails are 8" long.

History and variants

The XCR was designed in 2004 by Alex J. Robinson of Robinson Armament Co. Production of the XCR-L variant of the rifle began in mid-2006.
The XCR-L is currently available in 5.56mm, 6.8mm Remington SPC and 7.62x39mm cailbers.^[5] Each of these calibers is available in kit form for converting an existing rifle to one of the other calibers.
The 6.8 Remington SPC variant began shipping in November of 2007.^[6]
The 7.62x39mm rifles and conversion kits began shipping in July 2008.^[7]
In August 2009 Robinson Arms began shipping 3 different sized upper receivers enabling PDW and pistol style variants:^[8]

• Standard Upper Receiver - The original length and designed to support barrel lengths from 11" to 18.6".
• Mini Upper Receivers - 15.25" long and designed to support barrel lengths from 9" to 18.6". Primarily intended for barrel lengths from 9" to 10".
• Micro Upper Receivers - 13.25" long and designed to support barrel lengths from 7.5" to 18.6". Primarily intended for barrel lengths from 7.5" to 8".

Variants are also available in "California" versions which are limited to meet the more restrictive State of California firearms laws.
Since its introduction in 2006, components of the XCR have been updated. Most of these enhancements are available to existing XCR owners.

• In November 2006 the firing pin was redesigned and made more durable and robust. ^[9]
• The first few hundred XCRs shipped with Yankee Hill Machine (YHM) back up iron sights (BUIS). The most recent iteration ships either without BUIS or with BUIS designed by Midwest Industries.
• A 2nd generation adjustable gas system started shipping with XCR rifles in July 2007. The 1st generation gas system required tools (a 5/8" wrench) to adjust. The 2nd generation system can be adjusted by hand.^[10]
• The XCR's hammer was updated in July 2008 concurrent with the release of the 7.62x39 rifles/kits. The new heavier design allows the XCR to ignite some newer Wolf 7.62x39 ammunition made with extra-hard primers.^[11]
• In early 2009 Robinson began shipping rifles with an integral winter style trigger guard and new paddle style safety. A provision for a quick detachable sling loop was added to the stock mount.
• A two stage match trigger is available which will break at approximately 3.5lbs. This trigger can be ordered with a new rifle or retrofitted to an older one. The older one was a two stage trigger that was about twice as heavy, and some complaints included trigger slap. As of May 2009, the trigger has been shipping with all new rifles.
• Ambidextrous mag release was demonstrated at SHOT 2010 and is expected to be made available in the future.