Armalite the Only AR-10
BUILD AN AR 10
So you decided you want to build an AR-10 and your internet search delivered you to this site 308AR.com and that’s a great start. The problem is years of misinformation from word of mouth, published media and now the internet has steered many shooters down the wrong path in both purchasing rifles and building their own from parts bought online. To clear this up and educate visitors we will start with a brief little historical information and some misconceptions.
ARMALITE is the ONLY AR-10
The AR-10 is a trademarked model designation of a rifle model from ARMALITE. No other large frame AR .308 should be referred to as an AR-10. This is the reason I started referring to other brand weapons as 308AR (AR308). Inevitably I get email and negative comments on the subject but here’s why I stick to my guns in using proper naming. That reason is compatibility. These large AR rifles do not share the same interchangeability as their AR-15 counterparts and that is very important. I like to use analogies when this subject comes up. All muscle cars are not Mustangs, all bolt action rifles are not model 700’s and all Cola’s are not Coke. ARMALITE is the ONLY AR-10. If you want to build an AR-10 head over to Armalite and order an authentic AR-10 UPPER RECEIVER/AR-10 LOWER RECEIVER. I promise you it is the only lower receiver stamped AR-10.
There is no MIL-SPEC AR-10 308AR
There is no Mil-Spec AR-10 or 308AR. Any marketing material stating otherwise is misleading. What can be made Mil-Spec is materials and finishes. Dimensionally there is no MIL-SPEC with regards to parts. The interchangeability and that’s where the confusion of the platform comes in to play. The 308AR platform is full of inconsistency and a lack of interoperability. Armalite itself has two different styles of AR-10, DPMS has multiple receiver heights on their LR-308 rifles, the DPMS SASS has a proprietary barrel and gas system. Then there’s the DPMS G2 which is an entirely new platform all together. Rock River Arms, POF , all more different than the rest. Once again if you want to build an AR-10 visit Armalite. If you want to build a 308AR and have some flexibility look towards companies like Aero Precision and Mega Arms as solid bases to begin a 308AR build. Their hardware is first rate and very generic in the way you want it. Of course there is other equally suitable brands but you need to do your homework in advance.
The AR-15 was derived from the AR-10
There is a misconception that the AR-10 is based on the AR-15. This is completely false. First off AR in AR-10 and AR-15 stands for “ARMALITE RIFLE” and not assault rifle. The AR-10 was developed by Eugene Stoner in 1956. The AR-10 was re-scaled one year later and became the AR-15.
DO YOU STILL WANT TO BUILD AN AR-10?
DO YOU STILL WANT TO BUILD AN AR-10 or would you prefer to build a 308AR? If you still want to build an AR-10 I suggest buying a complete rifle directly from the Armalite. Building an Armalite AR-10 from parts will be a costly endeavor with no benefit over purchasing a rifle from Armalite. If you now realize and understand you want to build a 308AR by all means browse the pages of this website and have at it. The experience is quite rewarding.
I suggest visiting the following links before you proceed.
308AR Bolt Catch Screw Bolt Catch Pin
Early on at 308ar.com we did a page that referenced the the point that the Armalite AR-10 utilized a BOLT CATCH ROLL PIN same as the Armalite M-15 (AR15) rifle while the DPMS LR-308 308AR and similar rifles utilize a BOLT CATCH SCREW. Well despite that page we still get many questions about this small part. Based on these messages I decided a simple picture might be easier to understand in this day of sort attention spans. While I believe there are a small minority of 308AR manufacturers using BOLT CATCH ROLL PINS just as there is an AR15 manufacturer or two have adopted the BOLT CATCH SCREW feature. This post is meant to make folks aware of the differences.
308AR BOLT CATCH SCREW SOURCES
At this point I cannot definitively state what 308AR rifle manufacturers use the threaded BOLT CATCH SCREW or the BOLT CATCH ROLL PIN. Feel free to contact us and let us know whether your lower utilizes a BOLT CATCH SCREW or BOLT CATCH ROLL PIN
308AR AR-10 Manufacturers who utilize a BOLT CATCH ROLL PIN
308AR BOLT CATCH SCREW
Can I shoot 308 in an AR 15? Picture of a 308AR/AR-10 and AR15 receiver set
Can I shoot 308 in an AR 15? That is still by far the number one question I receive personally from shooters looking for more power and range than the AR15 and any of it’s available calibers are able to deliver. Of course the simple answer is “NO” but humans are curious by nature and we tak nothing at face value. We like to know “Why” or in this case “Why cant I shoot 308 in my AR15?”. I could simply explain that the cartridge is too long for the magazine and action.A .308 proportioned barrel is too large in profile to adapt to an AR15 receiver etc… BORING…. I thought it far better to take a bunch of pictures and throw them up an a single page. Please by all means share the pictures and the page just give credit and share the link where possible. Enjoy
Visit the 308 AR15 page pictorial at this link
As a side note to this post if there is something you would like to see covered at this site please drop us a line and let us know. Lets sort out this AR15 308AR AR-10 stuff in a way regular folks can understand. View our contact page here
Can I shoot 308 in an AR 15?
AR15 Trigger In a AR-10
One of the most common questions we get on the forum or facebook is “CAN I USE AN AR15 TRIGGER IN A AR-10 or 308AR?“. Well the answer is not black and white. Most AR15 triggers will in fact physically fit and function in a current AR-10 and 308AR rifle. However the reason AR-10 and 308AR specific triggers exist is for one main reason, military primers. The primers in military ammo often require more energy to ignite the primer than .223/5.56 ammunition. The way they extra energy is achieved with a heavier hammer and a more powerful hammer spring. If you look closely at the picture above you can see that Pact in their AR Gold and SR Gold Triggers increases the height of the hammer slightly to gain the extra mass.
There are many shooters successfully using AR15 TRIGGERS in their AR-10 and 308AR rifles however the risk is reliability. Our suggestion is always utilize a trigger that is specifically stated by the manufacturer to work in a AR-10 and 308AR rifle. There is typically no cost difference unless you want to utilize the least expensive triggers or a AR-15 TRIGGER with a TRIGGER JOB. In either of those cases I would have to ask why bother? Remember a quality trigger is the single best improvement you can make to any AR-10 and 308AR rifle. Skimp elsewhere.
AR15 Trigger In A AR-10
SI Defense 308AR Bolt Catch Screw – Stainless Steel
Armalite AR-10B Lower Parts Kit 10LRPK-T
308AR AR-10 Bolt Catch Pin – The bolt catch pin, one of the smallest parts on the 308AR, AR-10 and AR-15 platform weapons is a part that can stop an AR-10 308AR build dead in it’s tracks if you didn’t purchase the correct one or the correct LOWER PARTS KIT for your STRIPPED LOWER RECEIVER. Here’s why. The AR-15 platform uses a roll pin and that’s taken for granted when shooters move up to the AR-10 and 308AR platforms. Unfortunately this is where the topic gets muddy.
Armalite EL0220 AR-10 Bolt Stop Pin
The Armalite AR-10 utilizes a roll pin Armalite part number EL0220 which is the same as their M-15/AR15 rifles. while DPMS LR-308 based weapon utilize a proprietary hybrid pin/screw.
DPMS 308AR Bolt Catch Screw
This screw is essentially set screw who’s threads have been removed from one end creating a hybrid screw type pin. Now unfortunately though not all DPMS LR-308 based LOWER RECEIVERS utilize the hybrid BOLT CATCH PIN. Some manufacturers utilize the roll pin method identical to the Armalite AR-10.
Now further complicating the mix at least one AR15 manufacturer has begun utilizing the hybrid screw rather than the milspec roll pin used universally on the platform for decades.
Brownells Roll Pin Holder Set
See our page on roll pin tools here
308AR AR-10 Bolt Catch Pin
Aero Precision Extended Magazine Catch Button APRH308185
So you have that brand new Aero Precision M5 308AR lower or perhaps even another brand and you notice the magazine catch button is literally hanging by a thread or two after assembling. Aero has solved this with a $5 part (that Brownells should also offer). That part is Aero Precision Product Sku: APRH308185 Aero Precision M5 Extended Magazine Catch Button.
Aero Precision M5 Extended Magazine Catch Button -The Extended Magazine Catch Button is a drop in replacement for the standard lower receiver magazine catch button. This extended button is longer, allowing it to protrude the proper distance when used with our M5 Lower Receiver.