Questions about AR Build

[Brandon B]

hello fellow high-roaders

I am going to be building my first AR15. I’m quite familiar with AR platform, as I have quite a few.
(Armalite m15a4, RRA LAR15, DPMS, and a Spikes)

But here’s where I’m lacking experience and confidence- I’ve never built my own, so I am looking for advice on how difficult this actually may be. I already know what milspec upper I want, and it’s already put together from factory. Now I want a mil spec lower, but since I’m in CA my FFL is telling me they can sell me a lower parts kit and the stripped lower, but cannot put it together for me. Something about “putting together the lower in our shop is considered manufacturing and we are not allowed to do that here in CA”

I’m not sure if this is true, or only true to this FFL but they are a great shop and I’m choosing to go through them for my transfer of lower. So now let me get to my main question(s)

1- what is a good quality mil spec lower?
2- what is a good quality lower parts kit?
3- how much of a pain is it going to be for me (someone who’s never put together a lower receiver) to install all parts on the lower (trigger group, mag release, bolt catch, buttstock and buffer tube, etc.
4- what basic tools will I need, if any?

All information will help! Thanks guys
B

 

[FL-NC]

1. There are no "mil spec" lowers, as true "mil spec" lowers are full auto capable, and are manufactured, inspected, and packaged under standards that no other lowers in the industry see. That said, any of the major brands are equal. the best deal is PSA blemished lowers when available. 2. As far as a LPK, either PSA or DPMS is what I use for most builds. 3. Its not difficult to build for me, but I have done who knows how many- for myself, friends, customers, and repairs on military weapons. I have no idea how "handy" you are with tools. I'm sure there are videos out on how to do this, probably on you tube. The BEST way to do your first one is under the supervision of someone who has done a few. Otherwise, I think you are guaranteed to break something or at least launch/lose a part or 2, or scratch your gun up. 4. As far as tools, you will need basic hand tools like screwdrivers, punches, needle nose pliers, small hammer, etc., but you will also need an armorer's combo wrench, a torque wrench, a vice, and an upper receiver block or barrel blocks, at minimum.

 

[<*(((><]

1. Anderson Lower $30-40 (Primary Arms runs sales quite often for $30), or Palmetto State Armory stripped lower for ~$40; my main suggestion would be to stay away from polymer lowers, I don't see the point in them.
2. I would buy a lower parts kit minus the fire control group from Palmetto, order the buffer tube, buffer and spring, and stock at the same time) Buy a Larue MBT trigger group (they run sales for $100 periodically). If you want you can buy the Palmetto State Armory EPT (enhanced parts kit) I've heard the trigger is not bad on that one for affordability.
3. It's easy and requires basic tools, there are plenty of youtube videos out there.
4. Vice, vice block, punches, hammer, screwdrivers, allen wrenches (for lower installation) tape to protect lower when using punches, for upper sometimes specialty barrel nut tools are needed for proprietary handguards and the like, if not a multi function AR tool should work for most. A 1/2" torque wrench for torquing barrel nut.

 

[WestKentucky]

Lowers are easy. There are plenty YouTube videos that will walk you through it. My first build I followed the Larry Potterfield video and had my lower together much quicker than I expected. Buy the pieces and have fun.

Only things you need are a small hammer, a small punch, and a castle nut tool for the buffer tube. If you really tried you could probably get by with a hammer, a nail, and a screwdriver to tighten the castle nut.

 

[Armored farmer]

Get the proper tools. You will get along much better.
Its easy, fun, and rewarding.

 

[JeeperCreeper]

To answer question 3:

Not really hard at all if you watch a good tutorial and take your time. You are "assembling" a lower so all the parts should fit and be reasonably pain free. The hardest part is the trigger group because having a third hand would help. I'd say a lower should take about 1.5-2 hours if you take your time, have good tunes, and good beer.

To answer question 4:

For tools, a good punch set (brass) is a life saver. My first build I did without specialized tools: I used a vice grip, screw driver, and a set of allen wrenches for the whole thing. It worked pretty decent, but I've only done that once. You don't need to drop a ton of money on specialized tools, assembling a lower is more an exercise in precision fine motor skills.

Here's my favorite tutorial.

 

[Brandon B]

1. There are no "mil spec" lowers, as true "mil spec" lowers are full auto capable, and are manufactured, inspected, and packaged under standards that no other lowers in the industry see. That said, any of the major brands are equal. the best deal is PSA blemished lowers when available. 2. As far as a LPK, either PSA or DPMS is what I use for most builds. 3. Its not difficult to build for me, but I have done who knows how many- for myself, friends, customers, and repairs on military weapons. I have no idea how "handy" you are with tools. I'm sure there are videos out on how to do this, probably on you tube. The BEST way to do your first one is under the supervision of someone who has done a few. Otherwise, I think you are guaranteed to break something or at least launch/lose a part or 2, or scratch your gun up. 4. As far as tools, you will need basic hand tools like screwdrivers, punches, needle nose pliers, small hammer, etc., but you will also need an armorer's combo wrench, a torque wrench, a vice, and an upper receiver block or barrel blocks, at minimum.

Thanks for clearing that up. I could have sworn I saw my FFL advertising mil spec lowers. I guess they were falsely advertising Lol!

And as far as handyness goes I’m very handy. I’m an electrician and also do a lot of side work in various different aspects of construction. After watching a video today I believe I’ll be able to do it just fine. But watching and doing are two totally different breeds

 

[Brandon B]

1. Anderson Lower $30-40 (Primary Arms runs sales quite often for $30), or Palmetto State Armory stripped lower for ~$40; my main suggestion would be to stay away from polymer lowers, I don't see the point in them.
2. I would buy a lower parts kit minus the fire control group from Palmetto, order the buffer tube, buffer and spring, and stock at the same time) Buy a Larue MBT trigger group (they run sales for $100 periodically). If you want you can buy the Palmetto State Armory EPT (enhanced parts kit) I've heard the trigger is not bad on that one for affordability.
3. It's easy and requires basic tools, there are plenty of youtube videos out there.
4. Vice, vice block, punches, hammer, screwdrivers, allen wrenches (for lower installation) tape to protect lower when using punches, for upper sometimes specialty barrel nut tools are needed for proprietary handguards and the like, if not a multi function AR tool should work for most. A 1/2" torque wrench for torquing barrel nut.

As far as I’ve heard the upper is more tedious, luckily I’m ordering a complete upper. Thanks for the info. Really helps me out. Looking to buy all necessary tools before, then purchasing everything to build

 

[redneck2]

One of the little tricks is to grind a very slight taper on the end of the roll pins before driving them in. Chuck them in a drill and run them across a really fine file, some crocus cloth, or better yet a running bench grinder. Just a Little is all it takes.

trust me on this.

Watch maybe 4-5 YouTube videos and you’re good to go. Helps to have two guys.

 

[Powder296]

I never understood the love affair with "mil spec" parts. More often than not, we can build a far better rifle without using them.

The obvious example is triggers. How many free mil spec triggers are out there because we changed them to something better? I did a metric ton of research before I built my first AR. The number one improvement was trigger, number two was going to mid length gas. A mil spec barrel is carbine, and that doesn't include finish or material

 

[Hokie_PhD]

Congrats and welcome to the wonderful world of AR building.

One warning, it’s HIGHLY ADDICTIVE

As far as what you need, since you’re and electrician you probably have everything you need except the wrench to tighten the stock nut and those aren’t very expensive if you shop wisely.

Just be sure to use lots of tape on the lower to make sure you don’t scratch it. Otherwise watch the videos and take your time.

You did miss Primary Arms $30 sale this weekend. Get on their mailing list and wait for the next time.

Also PSA has lots of options for deals on LPKs. I’d suggest getting one with the ALG trigger. They’re nicer than a stock one but not very expensive.

Other than that, enjoy and condolences for dealing with CAs illegal laws.

 

[JeeperCreeper]

*snip* I’d suggest getting one with the ALG trigger. They’re nicer than a stock one but not very expensive.

*snip*

I agree with this. I've also had good luck with the Anderson stainless trigger (if you get an Anderson LPK) as well as the PSA EPT trigger. The standard PSA trigger I used once was garbage and replaced it.

If you are wanting a more custom/fancy trigger, I really like the POF drop in triggers. They come with KNS anti-rotation pins and little polyurethane "feet" that keep it tight in the action. I think JoeBob Outfitters and Aim Surplus had the cheapest prices. I have the 4.5 pound version and it breaks clean with an insanely short reset.

 

[someguy2800]

Easy peasy, it takes like 15 minutes to put the lower together. The barrel and gas block is a bit more fiddly. Get the action vise and barrel wrench for $25 on ebay. A set of roll pin punches makes it much easier but not required.

 

[Everready73]

I think the Aero Precision lowers when on sale for $50-60 are the sweet spot for value. Better QC than Anderson and PSA, little better finish. Chances are the Anderson or PSA would be fine though, I just think the $10 premium is worth it.

For a lower parts kit check it Son's of Liberty Gun works blaster kit. It doesn't have trigger or grip, but most change those out anyway. High quality parts with correct materials and coatings. No MIM mag releases etc like in the cheaper kits

Granite Ridge Outfitters and Shuyler Arms are good places for Aero lowers for best pricing.

The Larue trigger previously suggested is great for the money. If you wanted to spend less Joebobs was blowing out the Hiperfire EDT triggers for 60 and they are a little better than the ALG IMO

 

[Walkalong]

1- what is a good quality mil spec lower?

Lots of choices out there. The Anderson is popular and works well. PSA has one that also works well. I also have/have had a Mega, a Surplus Arms & Ammo, a Anvil Arms, an Aero Precision, an RRA.....Pick a logo or a price you like and go for it. I worried it to death the first time I was looking to buy a stripped lower. Everyone was correct, pick a logo you like and get it.

http://www.primaryarms.com/anderson-manufacturing-ar-15-stripped-lower-receiver-ar-15-a3

 

[Brandon B]

I never understood the love affair with "mil spec" parts. More often than not, we can build a far better rifle without using them.

The obvious example is triggers. How many free mil spec triggers are out there because we changed them to something better? I did a metric ton of research before I built my first AR. The number one improvement was trigger, number two was going to mid length gas. A mil spec barrel is carbine, and that doesn't include finish or material

do you think a mil spec lower would be compatible with a upgraded non milspec trigger? I’d like to put a nice trigger group in mine. I just mostly am looking for mil spec lower because my upper is mil spec and want it to fit nice with no play

 

[Brandon B]

Lots of choices out there. The Anderson is popular and works well. PSA has one that also works well. I also have/have had a Mega, a Surplus Arms & Ammo, a Anvil Arms, an Aero Precision, an RRA.....Pick a logo or a price you like and go for it. I worried it to death the first time I was looking to buy a stripped lower. Everyone was correct, pick a logo you like and get it.

http://www.primaryarms.com/anderson-manufacturing-ar-15-stripped-lower-receiver-ar-15-a3

Thanks! I’m beginning to find that out myself. I keep hearing most of them come from the sale manufacturer anyways, then the company slaps their logo on and sells

 

[JeeperCreeper]

I always considered "milspec" to mean "dimensionally" and not top quality as milspec is the bare minimum. Basically, milspec means (should mean) that parts are universal.

Most AR parts today will all be the same size and should fit, as everyone got on the milspec bandwagon about 7 years ago.

The only thing you really have to worry about if you're buying stuff from regular sources, is small vs large trigger pins...

 

[equin]

I built my first and only lower last year. As was said above, it’s fun and addicting. I think I enjoyed building it more than shooting it, and I really enjoy shooting it. The only tool I didn’t have was a vice, and it was still easy, for me at least, but I’ve R&R’ed transmissions, front and rear differentials, suspensions, axles, torn open transfer cases, etc. If you’re an electrician, I’m guessing you’ll find it fairly easy, too. I watched a few youtube vids on how to do a lower without a vice and all the other tools normally used, and that helped a lot. Of course, if you have a vice and all the tools, that just makes it that much easier.

I’m still fairly new to ARs, so I can’t comment on “milspec” or what LPK is best. FWIW, I used a Stag Arms stripped lower I got at a LGS and ordered online mostly Stag parts except for a BCM trigger group. I mated it to a Stag complete upper. Don’t know how “milspec” Stag is or how it ranks compared to other brands, but mine shoots great!

 

[someguy2800]

I did my lower on the kitchen table. I can't think of anything a vice would be needed for on the lower. Getting the barrel nut tight on the upper would be tough without a vice.

 

[Hokie_PhD]

do you think a mil spec lower would be compatible with a upgraded non milspec trigger? I’d like to put a nice trigger group in mine. I just mostly am looking for mil spec lower because my upper is mil spec and want it to fit nice with no play

There are many trigger options.
As long as they’re made correctly the issue is which one.

I suggested the ALG as it’s nicer than a bare bones mil spec trigger, it’ll fit and it’s not too expensive.

You can get triggers that are a bit more expensive than the ALG or much more expensive. For general use go ALG. Otherwise post your specific use and folks will post what they think are best.

 

[Brandon B]

I built my first and only lower last year. As was said above, it’s fun and addicting. I think I enjoyed building it more than shooting it, and I really enjoy shooting it. The only tool I didn’t have was a vice, and it was still easy, for me at least, but I’ve R&R’ed transmissions, front and rear differentials, suspensions, axles, torn open transfer cases, etc. If you’re an electrician, I’m guessing you’ll find it fairly easy, too. I watched a few youtube vids on how to do a lower without a vice and all the other tools normally used, and that helped a lot. Of course, if you have a vice and all the tools, that just makes it that much easier.

I’m still fairly new to ARs, so I can’t comment on “milspec” or what LPK is best. FWIW, I used a Stag Arms stripped lower I got at a LGS and ordered online mostly Stag parts except for a BCM trigger group. I mated it to a Stag complete upper. Don’t know how “milspec” Stag is or how it ranks compared to other brands, but mine shoots great!

Thanks for the help! Hey quick question for ya.

When you got your LPK, were all the springs and detents and pins all misconstrued together or were they all separated based on which part they assemble to? My main concern through all of this is figuring out which part goes where when it comes to pins springs and detents

 

[someguy2800]

Thanks for the help! Hey quick question for ya.

When you got your LPK, were all the springs and detents and pins all misconstrued together or were they all separated based on which part they assemble to? My main concern through all of this is figuring out which part goes where when it comes to pins springs and detents

My parts kit was from APF and it was seperated out in 4 or 5 baggies with piece of paper to decode which parts were in which bag. Don't stress over it, it's not complicated at all.

 

[Walkalong]

The first stripped lower I ever built up.

 

[Walkalong]

"Mil-Spec"

It really just means the critical dimensions are correct and cut outs for parts are in the right spot and the right size. You will see differences in the mag wells and other little things that don't affect function. My Mega lower has one of the better mag wells for speed. It was $100, and doesn't "work" any better than the $40 PSA blem lower I built. I still have one of the PSAs in the safe with either a PSA premium parts kit or a Surplus Arms & Ammo parts kit. Don't remember which for sure.

Not too long ago I bought a magnesium lower for $35 with a parts kit (Don't remember which one) from the same place. It would be perfect for a "lightweight" build.