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. The first that comes to mind is Aero Precision.
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.
AR15 Rifle Buffer vs AR10 Buffer
Can I Use An AR15 Rifle Length Buffer In My AR10 or 308AR Rifle Stock? That is a question we see pretty regularly on the forum and Facebook. The answer is of course no and the reason is simple. The AR-10 and 308AR Bolt Carrier Group are much longer than an AR15 Bolt Carrier Group. Using the AR15 rifle length buffer would not allow the AR-10 and 308AR to cycle completely.
So now your thinking how can a substantially more powerful cartridge use a shorter buffer? That too easy an easy answer or two. A Rifle Length AR-10 308AR buffer will weigh substantially more than an AR15 Rifle Length Buffer.The AR-10 and 308AR Buffer Recoil Spring will also be stronger offering more resistance. Slash of Heavy Buffers.com does a great job of sorting it out.
Update; Pat Raley our resident AR-10 expert offers up a more thorough and detailed explanation.
The buffers and buffer springs between the AR-10 / .308 style rifles and the M-15 series of rifles are different. Not just length, but weight also. They are both close in size but yet different enough where they should not be interchanged. Now as for receiver extension tubes… (this is mostly for ArmaLite rigles) There are 3, I say again… 3… I spell t h r e e different size receiver extension tubes. The rifle length is the same for the AR-10, as it is for the M-15. The carbine receiver extension tubes are different. The AR-10 is longer to allow the larger bcg to make the distance. In theory. .. you can not use an M-15 receiver extention on a AR-10.
(Another story at a different yime)
Carbine…..we will save that fo another post at a later date.
Armalite AR10 Carbine Stock Kit
Armalite AR10 Buffer Dimensions – To understand the differences between the Armalite AR-10, AR15 (M-15) and 308AR platforms is to have a good understanding of the dimensions involved in the buffer recoil system. The system includes the receiver extension tube or buffer tube, buffer and buffer spring. This page is strictly devoted to the Armalite branded weapons the Armalite AR-10 and Armalite M-15. This information does not apply to DPMS LR-308 and other 308AR firearms.
Armalite AR-10 Carbine
Armalite AR-10 Carbine Buffer Dimensions – 3 1/4″ Part Number EC0120
Armalite AR-10 Carbine Buffer Tube Dimensions – 7-5/8″ Part Number 10207025
Armalite AR-10 Carbine Spring Dimensions – Max 11-1/4″ Min 10-1/6″ Part Number EC0040
Armalite M-15 Carbine
Armalite M-15 Carbine Buffer Dimensions – 3 1/8″ Part Number EC0030R
Armalite M-15 Carbine Buffer Tube Dimensions – 6-15/16″ Part Number 15207020
Armalite M-15 Carbine Spring Dimensions – Max 11-1/4″ Min 10-1/6″ Part Number EC0040
Armalite M15 A2 Rifle Stock Kit
Armalite AR-10 Rifle
Armalite AR10 Rifle Buffer Dimensions – 5.2″ Part Number EA1090
Armalite AR-10 Rifle Buffer Tube Dimensions – 9-11/16″ Part Number EL0370
Armalite AR-10 Rifle Buffer Spring Dimensions – 14-1/8″ Part Number EA1095
Armalite M-15 Rifle
Armalite M-15 Rifle Buffer Dimensions –5 7/8″ Part Number EL0180
Armalite M-15 Rifle Buffer Tube Dimensions – 9-11/16″ Part Number EL0370
Armalite M-15 Rifle Buffer Spring Dimensions – Max 13-1/2″ Min 11-3/4″ Part Number EL0210
Armalite AR10 Buffer Dimensions
- AR15 PMAG Vs 308 AR LR20 PMAG
One of the subjects that often confuses shooters about the AR15 and 308AR is the size differences in the platform. We often hear “Can I shoot .308 in my AR15?” and the answer of course is no. I think one of the easiest way to illustrate the reason why is with AR15 PMAG Vs 308 AR LR20 PMAG size comparison. In the picture above it’s easy to see that the larger .308 Winchester cartridge requires a larger receiver, chamber and of course a larger magazine. A 308AR magazine cannot fit into the magazine will of an AR15.
View our 308AR compatibility page for further information.
AR15 PMAG Vs 308 AR LR20 PMAG