VISUAL DIFFERENCES M15, AR-10B, AND AR-10A COMPONENTS AR-10A VERSUS THE AR-10B

TECHNICAL NOTE 101:  VISUAL  DIFFERENCES AMONG  M15, AR-10B, AND AR-10A COMPONENTS
AR-10A VERSUS THE AR-10B
The  AR-10A family of ArmaLite® firearms is functionally identical to our AR-10B  family. Operation, controls, and  maintenance are the same.  However, the AR-10A family is designed to accept early ArmaLite AR-10 “Waffle” magazines and  good quality magazines copied from them, instead of ArmaLite’s proprietary aluminum  magazines that are used in our AR-10B family.   Neither family of firearms will function correctly with the other family’s  magazines.The  AR-10B magazine is based on the magazine of the famed M-14 rifle.  This magazine was adopted during the period  of the “Assault Weapons Ban”, during which new Waffle magazines couldn’t be  legally produced.  The AR-10B magazine  has proven to be as supremely successful in the AR-10B as its predecessor was  in the M-14, and ArmaLite will continue to offer it. We  have tested, we recommend, and we ship polymer Magpul PMAG® 20LR magazines with  our AR-10As.  Other similar derivative  magazines such as the KAC, M110, and DPMS / Remington 19 round magazines may  fit and may function, but we have not tested them so we can’t assess their  reliability.  You can purchase extra  PMAG®s from our website.Physical differences between the “Waffle magazine and the M-14 style magazine necessitate differences in some components used in AR-10As as compared to  similar components in the AR-10Bs.  Some components  of our AR-10A firearms are unique to that family.  For example, the AR-10A Bolt Stop, Magazine Catch,  Upper Receiver, and Lower Receiver are not the same as those in our  AR-10Bs.  This Tech Note will explain the  physical differences among those components.If  you need parts for your AR-10A, you may want to contact us to assure that you  are purchasing the correct parts.

BOLT STOPS

AR-10 Bolt Stops height=213

    M15                           AR-10B                              AR-10A 

As you can  see, the M15 and AR-10A Bolt Stops are similar in shape.  However, the AR-10A Bolt Stops are clearly  marked AR-10A.  And, if you look closely  at the upper left portion of those two parts, you’ll see significant visual differences between the two.The AR-10B  Bolt Stop is very different in shape than the other two.  Note the relatively large flat angled surface  near the top of the AR-10B Bolt Stop.

MAGAZINE CATCHES

AR-10 Magazine Catches height=116
     M15                           AR-10B                    AR-10A

Differences  among the three Magazine Catches can be seen in the shape of the boss on the right end of each catch.   (This is the boss that engages the cutout in the magazine body in order to retain the magazine in the lower receiver.)The M15 and AR-10B Magazine Catches are similar in design.   However, the magazine catch boss on the M15 Magazine Catch has a chamfer  on its lower side (shown in red above), whereas the AR-10B boss lacks that  chamfer. The AR-10A Magazine Catch is easy to differentiate from the other two.  Note that the boss on the right end of the  AR-10A Magazine Catch is rounded on its outer end.

UPPER RECEIVERS

AR-10 Upper Receivers height=516

               AR-10B (TOP)                          AR-10A  (BOTTOM)

The  M15 Upper Receiver is obviously smaller than the two AR-10 Upper Receivers, so  there should be no confusion with them.

The  AR-10B and AR-10A Upper Receivers are easy to tell apart if you look at them  from the bottom.  From the bottom, the two  flats near the front of the AR-10B Upper Receiver are very obvious.  The AR-10A does not have those flats. The two  divot cuts in the AR-10A Upper Receiver are less obvious, but clearly  visible.

LOWER RECEIVERS

AR-10 Lower Receivers height=516

               AR-10B (TOP)                        AR-10A  (BOTTOM)

The  M15 Lower Receiver is obviously smaller than the two AR-10 Lower Receivers, so  there should be no confusion with them.

The  AR-10A Lower Receiver has several obvious features that are not present on the  AR-10B Lower Receiver (in addition to the “AR-10A” logo on the side of the  AR-10A receiver).  Note the elevated  surface on the AR-10A that comes downward from the front of the magazine catch  cutout.  Also note the increased upward  angle of the bottom of the mazazine well on the AR-10A.   In addition, the shape of the boss around  the takedown pin hole is changed on the AR-10A.

© 2011  ArmaLite, Inc.  All rights reserved.THE WIZ &  N. BrinkmeYer