This manual is intended to instruct the Bushmaster Rifle Operator in all necessary aspects of Maintenance, Disassembly, Reassembly, Operation and Troubleshooting of any Bushmaster Rifle. Within the Bushmaster Weapon System, there can be infinite variations of Barrel Length, Stock Type, Receiver, Forend and Sights.
For purposes of this manual, the most common Bushmaster Model sold - the M4A3 Type Carbine - has been illustrated and photographed. A Parts Schematic for this model is shown below - many parts are common to all models in the Bushmaster System. The Bushmaster you own, or are using, may vary in appearance from the photographs and illustrations in this Manual, but the concepts, procedures and practices recommended in this Manual are universal to the Bushmaster Weapon System.
NOTE: See Carbon 15 Models – Differences for comparison and instructions specific to Disassembly and Maintenance for
NOTE: See Carbon 15 Models – Differences for comparison and instructions specific to Disassembly and Maintenance for those Models.
Note: For Carbon 15 “Flat-top & M4 Models, refer to previous XM15 E2S M4 Carbine diagram. The differences would be the substitution of molded Carbon 15 Receivers in place of forged aluminum receivers.
Carbon 15 Sighting Systems: Sights on Carbon 15 Rifles and Pistols vary from traditional AR-15 Type Rifle systems as shown below. All Rails on Carbon 15 Upper Receivers are machined from hard anodized aircraft aluminum in Picatinny configuration, and will accept a wide variety of scopes, optics, holographic, and red dot sights.
Beside the fact that they are molded Carbon Fiber material, the Upper and Lower Receivers on Carbon 15 Rifles and Pistols in the
“R” or “P” Series Models separate from each other in a different manner than XM15 E2S Bushmaster models with Aluminum Receivers. The disassembly steps are:
NOTE: These instructions apply specifically to these Models:
The molded Carbon Fiber Buttstocks on “R” Series Rifles can be easily removed from the Lower Receiver for more convenient storage or cleaning, or to gain access to the Buffer Tube. The disassembly steps are:
NOTE: A Youth sized Buttstock is available (2” shorter than standard - Part# AZ15279) to make shooting more comfortable for younger shooters and smaller women.
NOTE: Buttstock removal applies specifically to these Models:
The Stainless Steel Barrels on Carbon 15 “R” Series Rifles and P Series Pistols are fitted with an easily removed Quick Detach Compensator. The disassembly steps are:
WARNING: Do not fire the Rifle unless the Q.D. Compensator is firmly locked in place.
NOTE: The Rifle may be safely fired with the Q.D. Compensator completely removed.
Molded Carbon Fiber Receivers on Carbon 15 Rifles and Pistols have Safety Lever Indicator Markings either engraved into the Carbon Fiber material (most military / LE models), or inset into the Lower with colored letters (most Commercial models). S = SAFE (white
letters on both sides of Receiver); F = FIRE (red letters on both sides of Receiver). Compare with roll-stamped markings on
Aluminum Receiver at right.
While the Aluminum Receiver XM15 Models include the original military design, spring loaded, metal Ejection Port Cover, the Receivers on Carbon 15 Rifles and Pistols do not. The Bolt Carrier can be easily removed for cleaning and maintenance, so the Ejection Port Cover is not found on the Carbon 15 Models.