Best Lower Receiver + Bolt Carrier

[flyfish13]

My favorite lower receiver so far is the ADM UIC with ambidextrous bolt hold open, funnel mag well, but it's billet and more costly, but the bolt hold open feature alone is worth it to me.

The best forged lowers I've used are from Precision Firearms, Wilson Combat, and Les Baer, especially when purchased as a matched set.

Common forged lowers that work fine are PSA and Aero. Beware of lowers out there that are 6061T6 and not 7075T6.

What I've seen with 6061T6 receiver sets is that they loosen up quickly if that matters to you. There are some companies that slipped it by that they weren't using 7075T6, since it's much faster and cheaper to cut 6061 on the machines. It's perfectly fine for handguards, but was proven in Army testing in the 1960s to not hold up well when used on receivers. It also corroded more quickly since the anodizing didn't have as hard of a base to work with.

Lower Parts Kits are not created equally. Many out there for a long time used really cheap springs, pins, zinc-coated detents, and untested steel that would actually fail, especially hammer pins and bolt catches.

DoubleStar/ J&T has LPKs with the correct materials like cadmium-plated detents, MPI'd bolt catches, disconnectors, etc. Bad disconnectors were really common on a lot of the 2000s-era DPMS LPKs. Who knows what is out there in the current race to the bottom on pricing.

At SHOT Show, I've seen dealer AR15 parts kits master lists with everything but the lower receiver on a list from Taiwan, where the whole parts kit cost maybe $189-$215.

After over 3 decades of being eyeball-deep into everything I could be in the AR world, I'm setting a personal rule to spend more on components from a smaller source list generally, especially when it comes to barrels, bolts, receivers, LPKs, RETs, action/recoil springs, gas blocks, gas tubes, pins, triggers.

Interestingly, the charge handle market has increased in quality and options, as has the handguard market.

I have no problem with some of the cheaper handguards, but will spend top dollar on bolts, barrels, receivers, MBT-2S triggers (actually pretty low cost), charge handles, 7075T6 RETs, quality action springs, gas tubes, gas blocks with tight dims, etc.

At the end of the day, the LaRue Ultimate Upper Kit is the deal to beat really. No worries about fitment, top-shelf components, probably the best RET on the market, excellent furniture, super slim, super rigid harndguard and mate-up with the upper receiver only slightly bested by the behemoth LMT MRP monolithic and proprietary barrel system.

I know this is a dumb question but what does “RET” stand for?