AR15 Lower Receiver Parts

Don’t forget your lower parts kit and buffer tube kit to complete your 80% rifle build! 

What’s In An AR-15 Lower Parts Kit?

AR-15 lower parts kits will typically include the following parts:

• Trigger spring

• Trigger pin

• Trigger guard assembly

• Hammer

• Trigger

• Hammer spring

• Hammer pin

• Disconnector and spring

• Bold catch

• Bolt catch plunger

• Bolt catch spring

• Bolt catch roll pin

• Selector

• Selector detent

• Selector detent spring

• Takedown detents and spring 

• Pivot pin

• Rear takedown pin

• Burger retainer and spring

• Magazine catch

• Buttons and springs

• Screws and washers 

Sometimes these LPK’s will also include a mil-spec pistol grip, other kits may not include it which some buyers prefer. 

What Is A Buffer Tube Kit?

A buffer tube kit allows the stock of a rifle to attach to your build. The buffer tube itself will have holed notches which is how retractable butt stocks can switch different position lengths. Fixed stocks will take up the whole length of the buffer tube and not be able to utilize those different positions. 

Within the buffer tube is a buffer weight and a spring. This is what allows the bolt carrier group to ride back and forth, creating the cyclic action making the AR9/AR10/AR15 a semi-automatic weapon.