[Yo-Yo]

That’s where the Plum Crazy lower comes in handy on a sub-$500 build. It is around $125, and it is a complete lower with all internals, buffer and buffer tube, and adjustable buttstock. Literally lock in an upper and you’re ready to go.

Except it’s all plastic except for springs, buffer, and bolt catch. The rest of the lower, oncluding the hammer, sear, trigger, safety, mag catch, and even the take-down pins are plastic.

[Ocean Ranger]

That’s where the Plum Crazy lower comes in handy on a sub-$500 build. It is around $125, and it is a complete lower with all internals, buffer and buffer tube, and adjustable buttstock. Literally lock in an upper and you’re ready to go.
Except it’s all plastic except for springs, buffer, and bolt catch. The rest of the lower, oncluding the hammer, sear, trigger, safety, mag catch, and even the take-down pins are plastic.

The Cav Arms lowers (including the ones they built for ArmaLite and - from what I was told - Sabre Defense) use standard AR internal parts, except for the buffer tube and a few associated parts (built into the Cav Arms butt stock), the take-down pins, and (IIRC) a small roll pin needed to retain the buffer retainer pin/spring. I had not heard of the Plum Crazy lower - thanks for the info!