The AR15 and AR10 are quite similar in design, in handling, and in function. Some of the parts are slightly different, however, a lot of the AR15 parts are interchangeable. The main difference between the two is the size. Since the 308/7.62 is so much larger than the 5.56/223, the lower and upper receiver must be larger to accommodate the round.

AR15 parts that do not interchange well with the AR10 are mainly in the upper receiver. This includes the barrel, gas system, rails, bolt carrier group, and main upper receiver. All of these parts are simply way too big to interchange with the 5.56 round.

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In the lower receiver, it gets a little bit trickier. AR10 lower receivers are not universal by any means, so it can be fairly difficult to pair them with AR15 parts. The two main lower receivers used are the Armalite lower and DPMS lower. We use the DPMS lower for many reasons including the fact that it is cheaper, easier to find magazines, has more upper options, and is more reliable. 

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Neither lower can use the same buffer and buffer spring as the 5.56 because the 308 round is more powerful. A standard AR15 buffer can’t take the pressure. The Armalite lowers are compatible with some AR15 lowers, but a lot less than the DPMS pattern. This is simply due to the way the lower is designed.

A list of AR15 parts that will work with both the Armalite AR10 and DPMS AR10 is as follows: 

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• Trigger guard assembly (Billet lowers often have one-piece trigger guards.)

• Hammer and trigger pin

• Mag catch button

• Mag catch spring

• Ejector/Safety spring

• Buffer detent spring

• Disconnector

• Disconnector spring

• Bolt stop pin

• Bolt stop plunger

• Bolt stop spring

• Safety detent

• Trigger guard pin

• Pistol grip

• Trigger spring

• Hammer spring

• Detent (2 per rifle)

• Rifle receiver extension

• Buffer detent

• Buttstock assembly

• Buttstock screw

• Safety selector

• Hammer

• Buttstock spacer

• Standard trigger

• Detent spring

These AR15 parts are compatible because they do not need to be changed in size to accommodate the 308/7.62 round. They also do not need to be beefed up because they do not absorb pressure from the powerful 308 ammunition.

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One of the primary benefits to the DPMS lower is that it can use additional AR15 parts. This includes an AR15 buffer tube, but requires a different buffer and spring. It can also use an AR15 bolt catch and you can use most drop-in triggers. The few exceptions to the trigger rule is the McCormick straight trigger and RRA trigger.

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The benefit of using AR15 parts is mainly their price and availability. AR15s are a lot more popular than AR10s, so there is greater availability of parts. This is one of the main benefits to the DPMS pattern, especially since a quality trigger can easily be a hundred dollars.