Lower Receiver & Upper Questions

Guns & Gear
1

What makes a lower receiver a good/bad one? What makes an upper a good or bad one?

My goal is to build an ARP, I’m trying to put the math together on certain parts. I’ve seen expensive lowers on websites, and I’ve seen lowers that are somewhat inexpensive. What separates the two, besides being metal vs polymer?

What separates inexpensive & expensive uppers?

Any other info I should keep in mind, any “must know” info, anything I should specifically look out for when building an AR, etc etc… I am open to all/any information. I am an AR rookie.
Sites that I have been looking on have been PSA, AeroPrecision, BravoCo

Thank you for your time.

2 Likes
2

For one, forged is best. Avoid anything that is cast even though I’ve read some positives about one.

1 Like
3

I believe Forged 7075 series aluminum is the preferred composition.

2 Likes
4

Some of the price differences on them are the internals. You can get inexpensive lower parts kits, or you can spend a ton. Same with the uppers. I would concentrate on the material the lower and upper is made of, as stated above, and the bolt and bolt carrier and barrel. Most of the rest can be fairly easily upgraded in the future if you have a little skill.

I usually build (well, assemble) the lower and buy a complete upper.

2 Likes
5

I usually build my AR-15’s, it is a preference!
My opinion is:

Aluminum Lower- MIL specs is important.
Upper - MIL specs.
Barrel 1/7 Twist, 16" long
The rest is whatever you prefer.

2 Likes
6

Also, look for a hood BCG (Bolt Carrier Group). I’d look into one of M16 quality.

2 Likes
7

Enough info online to keep you busy forever. & PSA has some very good parts.

3 Likes
8

I’ve bought several from PSA. They look really goo to me. One day I’ll get around to finally assembling them.

3 Likes