Best Lower Receiver + Bolt Carrier

[flyfish13]

This will be my first build. Wanting to build the entire gun to educate myself. Need suggestions on best lower receiver + bolt carrier. After a lot of research I'm still not comfortable on what and which brand to buy. Probably will buy forged but not opposed to billet if its reasonable in price.

Are all lower parts kits the same?

Suggestions/Recommendations?

[Londerko]

Can’t go wrong with Aero Precision receivers imho
Most LPKs are close to the same, but put a good trigger in it
As far as BCGs, I run all Toolcraft and have had good luck, but the group buy monster bolt is a good deal

[flyfish13]

Doesn't Toolcraft make BCG's for other companies?

[Bigs28]

For the most part a forged lower is a forged lower from any reputable company. Anderson, aero, psa will all work the same as a 2a armament or v7. The bcg i use is a cryptic coatings. Not having to worry about lube makes me happy. If you want adjustable gas then the bootleg adjustable carriers are another great option.

[LRRPF52]

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.

[flyfish13]

Great information LRRPF52. Thank you.

[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?

[Jakegsxr11]

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

I had the same question...

[worthen86ford]

Reciever extension tube, aka buffer tube.

[Geardo]

Spikes Tactical has the best lowers, haven't used their uppers, Aero Precision makes nice uppers, best that Iv'e used Anderson Lowers are ok, sometimes the bolt catch roll pins holes have been a little tight, and the finish is a little sub par

[hootie6828]

I've used several different lowers, including Anderson and Stag, and I haven't had any serious issues with any of them. That said, I think my next few will probably be Aero Precision, I think they are hard to beat for the price vs features that you get with them.

[tracker12]

Very happy with my Toolcraft BCG

[flyfish13]

Thanks for the comments and suggestion.

[LRRPF52]

If you're doing forged receivers, the Alexander Arms receiver sets are actually squared away.

The upper faces on all the ones I've used are square out of the box, they have Mil-Std hard coat bake-on dry film lube (suspends lubricant better than straight anodized uppers), and are labeled "6.5 GREN".

For bolts, the JP Enhanced Bolt is top-shelf.

AA Hard Use bolts are top shelf, but I don't see them available on the AA website anymore.

The Precision Firearms bolts I've been using for many years now have been trouble-free and very smooth, great extractors too.

The Forum Group Buy bolts are holding up very well so far, including the one in my 12" CLGS suppressed pistol, which should be a harder set-up on the bolt than any of my rifles.

The only bolt carrier I see myself using for the foreseeable future is the Bootleg Adjustable Gas Carrier.

I have no financial connection with any of the above companies, and am making my comments solely based on real-world experience, but I'm only one man who can only walk in one path at a time. I personally choose a pretty harsh path to walk in terms of shoot schedules and conditions, and also get to see a lot more rifles that come through courses, so I base my perspective on what I've seen from those angles and share them for the benefit of everyone here.

[flyfish13]

If you're doing forged receivers, the Alexander Arms receiver sets are actually squared away.

The upper faces on all the ones I've used are square out of the box, they have Mil-Std hard coat bake-on dry film lube (suspends lubricant better than straight anodized uppers), and are labeled "6.5 GREN".

For bolts, the JP Enhanced Bolt is top-shelf.

AA Hard Use bolts are top shelf, but I don't see them available on the AA website anymore.

The Precision Firearms bolts I've been using for many years now have been trouble-free and very smooth, great extractors too.

The Forum Group Buy bolts are holding up very well so far, including the one in my 12" CLGS suppressed pistol, which should be a harder set-up on the bolt than any of my rifles.

The only bolt carrier I see myself using for the foreseeable future is the Bootleg Adjustable Gas Carrier.

I have no financial connection with any of the above companies, and am making my comments solely based on real-world experience, but I'm only one man who can only walk in one path at a time. I personally choose a pretty harsh path to walk in terms of shoot schedules and conditions, and also get to see a lot more rifles that come through courses, so I base my perspective on what I've seen from those angles and share them for the benefit of everyone here.

Per your suggestion the LaRue UU kit looks like a very good deal and high quality. Called them and it takes about 4-6 shipping. Looking more and more enticing. Will still get the experience of putting it together/building it.

[flyfish13]

Update. After researching the Larue UU kit I place an order this morning in FDE with a matching lower.