i'm gonna Form 1 my M400 for this very reason. back when i was making my first AR purchase and asked here, more than one forum member told me the M400 stacked up to the DD for half the price, and i went with it. no regrets.

 

What is a fair price for an M400 lower?

 

I’ve built many AR rifles and pistols and used PSA, Aero Precision, Anderson Manufacturing, Rainer Arms. I’ve also have two complete AR’s from Sig Tread M400 and a Daniel Defense M4 V7 Law Tactical. All of my custom built AR‘s lowers perform great with no issues.

On the high end my Rainer Arms lower cost the most and is spectacular and with a 10.3 barrel in 300blk out complete upper from DD it is a clone of my DD Law tactical, on low end Anderson manufacturing lower and uppers work well together and are budget builds. One of my good friends told me always good to have a few extra lowers in your gun safe for hard times. I picked up two before COVID and they sat in my safe until I couldn’t find anything in stock anywhere but had those budget lowers setting there…..lol

My favorite lowers are Aero Precision and have them in most of my inventory and best bang for the buck AR parts, never and I mean never have had a single issue with their lowers and uppers with no slop, or play between the upper and lower. On the Aero website they have a blemished sale area and I can’t see any differences in their blemished versus non-blemished lowers. Everything thing fits nice and snug and performs without a hitch.

Hope it helps brother. 😎


Yea both company don’t sell just lowers…..I checked as well when I started building AR’s for fun.

 

Before you do the paperwork on a lower, make sure you build it to make sure it functions with the parts you pick.

 

Buy a Wilson Combat lower and build it the way you want. No special tools are needed to build a lower.

AR Lower Receiver Parts and Accessories - Wilson Combat

Wilson Combat has been the innovator in custom pistols, long guns, and accessories since 1977. Home of the Wilson Combat 1911, EDC X9, WCP320, and more!

shopwilsoncombat.com

To the best of my knowledge Daniels and Sig do not sell lowers by themselves. I’ve built guns from Spikes and BCM as well. Those lowers are fine too.

Here is a 300blk I built out of Wilson parts. Eventually I’ll SBR it. I already have the barrel.

 

Much appreciated, Ken, but I'm not the building type...unfortunately, I'm not mechanically inclined. I like to just buy what works and then take problems to my local gunsmith.

 

Up to you but with all the videos on line, it’s super simple. Not any harder than screwing in a light bulb. you just have to screw it in a few times. Watch a few videos first, then make the call on wether you are willing to do it or not. Also.. if you don’t want to build it.. have your Gunsmith do it..

Building a lower yourself gives you the absolute best parts if you want, far below the price of buying one assembled. You know, I can’t think of any company that sells only a complete lower..

 

Palmetto State Armory has complete lowers.

https://palmettostatearmory.com/ar-15/lowers/complete-lowers.html

 

I just bought a blem ... but I ain't found the blem yet. I did find a dried booger like spot on the Mloc free floating hand guard, but no tellings where that come from. It might have been a wax? It fell off with a finger nail. BLEM PSA PA-15 16? Nitride M4 Carbine 5.56 NATO Classic AR-15 Rifle with 13.5? M-LOK Rail, Black | Palmetto State Armory The Palmetto banner is fancier than my last one's "COLT" stamp. There is a bright spot on the mag release button on a ridge.

 

Anything 7075 and billet with a matching upper receiver and maybe hand guard.










and FDE!

 

Aero lowers are super nice for the price. I have a few different kinds (makers) of uppers I’ve used on my lower with no fitment issues.

Mil-Spec AR Parts, Components & Accessories | Aero Precision

Aero Precision manufacturers mil-spec parts, including AR15 & AR10 uppers, lowers, rifles, handguards, barrels, scope mounts & more.

www.aeroprecisionusa.com

 

Thank y'all, gentlemen. I wonder if I should buy a high-end "full" AR and then SBR the lower so that I have all of the options. I think I can find a Sig M400 under $1,000. I'd store the full size upper for when I want to shoot 5.56 (which is rare) and otherwise put a short 300BLK or FiveSeven upper on it.

 

That will work, can even consider selling the upper off the complete AR rifle you pick to fund your SBR build. That said always good to have options with being able to shoot two different calibers platforms with one lower. Nothing against the Sig M400 because I have one but if you pick Sig on your build not a lot of complete uppers to purchase or barrels in different calibers. (I was just one their website).

If you go high-end you can get a SBR complete rifle/pistol ready to go with nothing else to purchase except a different complete upper in another caliber if you want.

 

Aero Precision are solid go-tos. Don't need to spend a lot to get a solid mil-spec lower. The M4E1 has a nice 'billet' look to it but fits all mil spec parts and uppers normally.

 

I agree, you don't need to spend a ton to get a good quality lower. Aero and PSA come to mind. I have two PSA AR's...One is a 16" 5.56 and I just did an 8.5" 300blk SBR. The 5.56 has a few thousand rounds through it with zero issues. The 300blk is new, but I expect the same performance.

 

Centurion Arms CM4 lowers are all I use when buying only an upper rather than the entire rifle. I have SBR'd five of them. Currently in stock. CM4 5.56 Forged Lower Receiver

 

You know, if you’re willing to go the full rifle route just buy a complete SBR and stamp it when you buy it. The stamp takes 14-45 days typically on a SBR to come in. So your shop will sit on the SBR till your stamp arrives.
Or buy a Pistol and SBR it.

 

Is there a place to look up all these terms like SBR, I'm not new to ARs but neither am I totally filled with all there is to know. It seems to me that one can buy a different caliber upper with matching bolt carrier to run on the one lower .... that's a question BTW. Example ... could I buy a 9mm upper and matching BC and out fit it and just swap on / off my lower at will?

 

SBR is for “Short Barrel Rifle” Yes you can buy different uppers and put on a lower, but you have to watch out what configuration you have going on. A butt stock, with a 10” pistol upper is now an SBR and with out a NFA tax stamp is illegal…

 

SBR = Short Barrel Rifle (less than 16").

As far as upper/lower caliber compatibility, yes, for the most part you can just add the upper. For instance, I can take my 300blk AR15 lower and put my 5.56 upper on it to switch calibers. And these two use the same magazine as well, so the switch is easy.

 

I use the CMMG Radial-delayed Blowback 9mm system as well as the 9mm Pmag inserts for it, so I can just switch uppers on my SBR lower...same buffer, just switch uppers. 5.56, 9mm and .300 BLK. Could even make a .22LR conversion as well.

5.56

300 BLK

9mm (Omega 9K silencer incoming)

 

What handguard is that on the 300blk? I'm trying to find a handguard that my supressor will fit inside (supressor has 1.55" diameter). Would also prefer a Vanguard that doesn't require a special barrel nut if possible.

 

Of course, that would be easier. I like building them so by the time I got to SBR'ing one of my pre-ban lowers I already had my 'kit system' going. But if you know there';s a 'pistol' version out there that had a barrel length you're after and don't already have parts/uppers/etc., then go for it. It'll end up being the same cost anyway.

Some folks also 'stock up' on lowers, buying them stripped...keeping some around just in case or for future builds...SBR's or full riffles. If you're in a state that doesn't have an assault weapons ban, you still have a lot fo leeway as to what you want to build, and with who knows what's on the horizon, maybe get some extra lowers while you can. Even the low-priced PSA and Anderson's will work just fine. I have a few just stored away.

But on the flip side, don't let the relative ease of building take away from the importance of quality of parts and construction, especially when it comes to the upper...which I've mostly bought complete or had a qualified gunsmith put together. Best to have someone who knows what they're doing check headspace and get alignment and gas tube right. That's why some makers cost so much, the parts construction/quality and build precision, tolerances and hand-fitting where necessary.

And of course, if you're buying the complete 'pistol', getting one of the solid mid-to-higher end manufacturers gives you that much more confidence in theirs. Probably hard to go wrong starting with like BCM and going up from there, budget allowing.

 

@Gilly19 - You don’t SBR a lower - you SBR a rifle. One of the inputs on the form is the overall length of the rifle.,,so you need to include the upper. Once that lower’s serial number is registered as an SBR, it becomes an NFA item - regardless of what upper is attached.

 

Navy87guy, you are completely wrong regarding your SBR post. Uppers are NOT considered firearms according to the ATF. Uppers do not have serial numbers, can be shipped directly to your home, and do not require background checks. It is impossible to register an Upper as an SBR.
AR15 Lower Receivers, even a Stripped Lower without any other pins, springs, etc. attached to it is considered a firearm. This piece of aluminum can only be shipped to an FFL, requires a background check, cannot be sold to a convicted felon, and has a Serial number stamped into it. This Serialized chunk of aluminum can be Form 1 approved by the ATF as a Short Barrel Rifle (SBR). Once this chunk of aluminum AR15 Stripped Lower is approved by the ATF, federal law requires you to engrave the name, city, and state on it. My Form 1 ATF Tax Stamp shows the barrel length as 12.5 inches, and overall length as 27 inches, although a barrel and overall length can legally be any other dimension. My Form 1 application was completed and submitted nt the Silencer Shop, the Premier Class III dealer in America. They have successfully submitted untold thousands of ATF applications - they know what they are doing.
To reiterate, ONLY LOWERS can become an SBR, UPPERS CANNOT become an SBR.

 

When I did it a year or so ago, you could still just do it with the lower if you knew what barrel length you were going to put on it. If you know you're going to be using multiple lengths, you can essentially just choose one (say 10.5' or 11.5" barrel), then approximate the overall length and put it in the application. Even if you don't have a buffer tube yet, someone will give you that measurement. At the time the only photo they needed was of the receiver with the serial number and manufacturer/model.

Maybe that's changed since then, but you didn't necessarily have to have the upper on hand, they wouldn't know if you did or didn't. And of course, you needed approval and tax stamp before you could 'construct' it and put a buttstock on.

If you need overall lengths with a 10.5", 11.5", or 14.5" barrel you can PM me and I'll forward them.

 

'Can't go wrong with a lower from Spike's Tactical either...and there are many to choose from. 'Not the least expensive, but good quality.

I used one of their "Crusader" theme lowers for my dedicated AR22 pistol build, which fell together nicely and functions 100%:

 

Nice looking configuration. 👌 What upper is that?

 

Spikes makes good stuff too.

 

LWRC or POF is ambidextrous.

 

Aero Precision, they make quality and reasonable AR receivers. I've used them on all my AR builds so far including my 308 AR.

 

Wow! All this discussion about lowers. Back when I built my first lower, all one needed was a proper mailspec lower. That would mate to any -15 upper. If you wanted super tight mating, there was a set screw installable on some lowers that applied enough pressure to insure proper, tight upper-to-lower mating.

There are differences in manufacturing lowers, but I doubt any of us will live long enough to wear out any lower, and as long as it’s milspec, it will perform fine. There are newer tricks to give some added reliability (non-walking pins, threaded rear spring retention holes) but the basic lower hasn’t changed much since its inception.

I avoid Anderson, but that‘s just because I think they are the lowest quality lowers, but they work too! YMMV.

 

Any 7075 Forged lower will do you well (Aero is a go to brand). If you want additional ambidextrous features, the Sig, POF and Radian are excellent. An affordable option is the Unbranded AR/ Zero Delta (look at everything they make actually)…

 

I highly recommend PSA Lowers (and Uppers). I have several PSA ARs, and they all run perfectly, and have LIFETIME warrantys. Putting my money where my mouth is, I did Form 1 a PSA Lower making it an SBR. I have expensive ARs (Daniel Defense, Adams Arms, and a Colt M16) but my PSA guns perform equally with the more expensive ones.