XCR PARTS GUIDE
The XCR-L is 10 years old this year! Over the years, the XCR has been sold in many different configurations. It was originally designed for the Special Forces Combat Assault Rifle (SCAR) Program. Above is an image of one of Robinson Armament’s SCAR rifle samples submitted for the SCAR trials but was never tested because of government corruption. There have been changes to some parts over the years. This page of our website helps you identify the parts you have so that you can order the correct replacement parts or Caliber Conversion Kits. The XCR was so well designed in the beginning that even the oldest XCR can be upgraded to have all the features of our most current models.
The XCR-M was developed later and has not changed much. Therefore, pictures of the XCR-M parts do not appear below but at the end, there is a link to the XCR-M Part List.
XCR-L LOWER RECEIVERS
There have been some modifications to the XCR-L Lower receivers. Below you can find and identify those changes
One of the items that has changed is the Bolt Catch.
There are two types of Magazine Releases – Type 1 and Type 2. Receivers that accept the Type 1 Magazine Release can be identified as having a flat front edge while the Type 2 have a rounded front edge. Please refer to the images below.
There are three different rear portions on the XCR-L – Type 1, Type 1 Modified, and Type 2.
Please note that a XCR-L Type 1 Lower Receiver can be modified to a Type 1 Modified Lower Receiver for a reasonable charge if sent to our facility.
Fire Control Parts
There are two different Sets of fire control parts for the XCR-L – Type 1 and Type 2.
The Type 2 Fire Control parts have a superior feel and trigger pull. These parts will fit in all XCR-L and XCR-M models. They can be purchased directly from the Company. If you like, we can install them for a small fee if you return your lower receiver to us.
XCR-L BOLT AND CARRIER
There are three different Types of XCR-L Bolts – Type 0, Type 1, and Type 2. There are two different types of XCR-L Carriers.
The Type 2 Bolt and Carrier is an improved system. All XCR-Ls can be upgraded to use the Type 2 Bolt and Carrier by modifying the Type 1 Lower Receiver to be a Type 1 Modified Lower Receiver as shown above. Contact us for more information.
The XCR-L Extractors are number have a number on the front. 5 is for 5.56, 6 is for 6.8, 7 is for 7.62x39, 3 is for .308. The 5.56 Extractor is also used for .300 Blackout and 5.45x39. The 7.62x39 extractor is also used for 6.5 Grendel. In 2016, we came up with a newer 5.56 Extractor which improves extraction. It should be used with the Omni Deflector mentioned lower on this page.
XCR Extractor Spring
There has been a change to the XCR-L and XCR-M Extractor Spring. Please note that the images below appear much larger than the actual extractor springs which are only about .5″ long.
The black and orange polymer springs have been replaced by two metal springs and a shorter detent as shown in the images above. The smaller spring goes inside the larger spring.
XCR-L OPERATING SYSTEM
The XCR-L can use four different types of operating systems – Type 0, Type 1, Type 2, and Type 3. We define the Operating System as the parts that cause the firearm to cycle (move). These parts consist of three Parts: the Gas Block, the Operating Rod (Oprod), and the Gas Tube.
The Type 0 Operating System (OS) is found only on the earliest XCR-Ls. It was discontinued because it was found that it did not cycle reliably when using calibers other than 5.56. The Type 0 gas block required a wrench to adjust the gas settings.
The Type 1 OS is found on most XCR-Ls. It has a gas adjustment dial on the Gas Block that has 5 positions – S through 4. There have been 2 variations of the Operating Rod (Oprod) using in the Type 1 OS. The Type 1 Oprod on top had a chamber behind the piston head which held some brass anti-bounce weights. These weights were found to be unnecessary and can be removed. Both of the Type 1 Oprods are interchangeable. The Type 1 Gas Tube has holes and a small notch on one side.
The Type 2 OS is almost identical to that found on the XCR-M MWS. It is a gas cut off system similar to that found on the M14 rifle. It has several gas adjustment settings. The Type 2 Gas Tube has no holes and no notches.
The Type 3 OS has a Gas Block with an 8 position gas adjustment dial – 0 through 8. It uses the Type 1 Oprod, but uses a Type 3 Gas Tube which has holes and a wider notch on one side. The Type 3 OS was designed for use on XCR-L Upper Receivers which require the Gas Block to be contained inside the Upper Receiver. The Type 3 OS can be used on any XCR-L.
There is much discussion on the web about advantages and disadvantages of a Long Stroke (Types 1 & 3) vs. a Short Stroke (Type 2). The fact is both work very well and a lengthy discussion here is not warranted.
It should be here noted that the images above are all of our Standard length OS. There are 4 different lengths that have 4 different length piston heads or extensions on the their Oprods and different length Gas Tubes. These OS lengths from longest to shortest are: Standard, Mini, Blackout, and Micro.
A link to the XCR- L price list can be found below.
There have not been many changes to the XCR-M platform. However, there are a few which improve the accuracy. Please refer to the image below.
The accuracy enhancement consists of a modified gas block, a new gas tube, and a new muzzle brake. Additionally, a barrel with a special chamber is used. This chamber is compatible with .308 and 7.62 NATO ammunition. These barrels are Marked as “.308 M 1/10”. All new XCR-Ms are shipped with these enhancements. These enhancements can be made to any XCR-M. Contact us for information and pricing.
There are now three XCR Stocks – the FAST 1, FAST 2 and FAST 3. Please refer to the images below.
The FAST(TM) 2 is the same size and shape of the FAST(TM) 1 but the length adjustment button on the bottom has been replaced two small buttons indicated by the red arrow on opposite sides of the stock. These buttons must be depressed simultaneously to adjust the stock length. In addition to the length adjustment buttons, there is a dial indicated by the green arrow on the bottom of the stock. This dial allows the sliding part of the stock to be firmly tightened so that there is no slop in the sliding parts of the stock.
The FAST(TM) 3 fits all XCR-L and XCR-M models. It folds, is adjustable for length, and is made from similar materials as the FAST(TM) 1 and 2. However, It has a LOP from 13″ to almost 17″ which, like the FAST(TM) 2, is adjustable via two small buttons (indicated by the red arrow) on opposite sides of the stock which must be depressed simultaneously. In addition to the length adjustment buttons, there is a dial indicated by a green arrow on the bottom of the stock. This dial allows the sliding part of the stock to be firmly tightened so that there is no slop in the sliding parts of the stock. The FAST(TM) 3 also has a longer straight cheek rest which has three positions for height adjustment. Its height may also be adjusted by bolting the stock at different heights to the hinge. It also has two additional QD sling mount holes on each side of the stock. This stock is truly comfortable and has all the adjustments target stocks do without the size, weight, and complexity.
XCR STOCK HINGES
There are two version of the XCR Folding Stock Hinges. Please refer to the images below.
XCR STOCK ADAPTERS
In addition to the stocks, we offer a Pistol Cap and other stock adapters. Please refer to the image below.
The Fixed Adapter is used in place of the hinge with the FAST(TM) 1 and 3 Stocks. This adapter does not allow the stock to fold.
The M4 Adapter is used to attach M4 type stocks to an XCR. The Tube of the M4 stock is mounted lower in relation to its height if mounted on an M4. It does not use the tear drop shaped plate that prevents rotation of the stock tube; rather it uses a set screw for this purpose.
The AR Adapter can accept almost any AR15 stock. The stock’s tube position is roughly the same height as the tube when used on an AR15 thus maintaining the cheek to sight height found on an AR15.
XCR Brass Deflectors
Below are the various Brass Deflectors that have been shipped with XCR Rifles and Conversion kits.