Building an AR from scratch. Just like mom used to make.

JimStevenson

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Hello Everyone,
I was wondering if anyone has any advice on building an AR from ground up from stripped parts. Stripped being, no pre assembled components and no/minimal parts kits. What are the steps (in order) that you felt worked well and prevented some problems down the road (ie. did you start with the lower and then buy the upper to test the fit between the two, and then start adding items to either, just in case there was some poor fit between and you had to strip down one of the two and start over?).

The most important part on the AR
I suppose this is a a tag-on question, but what single part do you think is the most important on the AR 15 in terms of spending the most money and or seeking the best quality possible (without having to sell your kids and dogs).

Thanks in advance for you tips and help!
 
Thanks, one tick for barrel. I see some advice that a good all around barrel can be purchased for around 300 bucks, but a great trigger can cost upwards of almost 400. So do we compromise on the barrel to gain a sweet trigger? Compromise = spend a medium amount, but still get something that does the job of a more expensive barrel?
 
Thanks, one tick for barrel. I see some advice that a good all around barrel can be purchased for around 300 bucks, but a great trigger can cost upwards of almost 400. So do we compromise on the barrel to gain a sweet trigger? Compromise = spend a medium amount, but still get something that does the job of a more expensive barrel?

NO!!! The barrel should be the number 1 priority. Buy the absolute best barrel you can afford/justify putting into the build.

Everything else (like the trigger) can be easily upgraded at any later time if found necessary or as/if funds permit.

Sacrifice on barrel quality from the start and nothing else you do to it can make up for the shortcomings of a subpar barrel.
 
^ + 1+2+3 Same tune as others for the barrel

Here's my 5 cents for accuracy/followup shots:

User ability > User ability > user ability >Barrel > Optics/Sights > Trigger > Muzzle brake (compensator) > BCG > Gas block (adj) > Buffer/spring selection > Handguard (freefloat) > Stock (LOP) > Grip

(not counting ammo which also plays a huge factor)


Edit: did I mention that user ability is the biggest factor? :) You can have the best gun in the world, and still perform abysmally if your shooter doesnt have the skill/patience/etc.
 
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I note that as of yesterday there was a new IBI barrel assembly in the EE for $300. One could do worse.

OP - when I saw "Building an AR from scratch" in the title of your thread, I assumed that machine tools were going to be involved. Then I saw that you want to assemble a gun from parts.

Might be an idea to decide what you want the thing to look like, and to what use you are going to put it. Mirror commandos prefer short, highly accessorized pieces, suitable for viewing in a normal width mirror. Competitive riflemen prefer less adorned units with quality components selected for performance back to 500m or more.
 
The three most important parts, in this order.

Barrel
BCG
Trigger

Everything else is just personally preference and won’t make much of a difference in how it shoots.
You could argue that matching your buffer weights to your gas system and barrel length is equally important but to me that’s just doing your dilligence. You wouldn’t build a race car and then put motomaster tires from Cambodia tire on it. Also room for optic on that list, but not necessarily as important as the others.

One thing I’ll make mention as you mentioned it in your post. “Receiver fit” is a myth in terms of accuracy and reliability. If there’s a bit of play between the two it’ll function and shoot no better than if it’s a super snug fit and vice versa. Personal preference not considered.
 
NO!!! The barrel should be the number 1 priority. Buy the absolute best barrel you can afford/justify putting into the build.

Everything else (like the trigger) can be easily upgraded at any later time if found necessary or as/if funds permit.

Sacrifice on barrel quality from the start and nothing else you do to it can make up for the shortcomings of a subpar barrel.

Okay great. What do you think is a great item to focus on? Assuming the gun parts you have are decent enough to get the job done, is there one part that you would throw money at?
 
^ + 1+2+3 Same tune as others for the barrel

Here's my 5 cents for accuracy/followup shots:

Barrel > Optics/Sights > Trigger > Muzzle brake (compensator) > BCG > Gas block (adj) > Buffer/spring selection > Handguard (freefloat) > Stock (LOP) > Grip


(not counting ammo which also plays a huge factor)


I actually forgot about optics haha. I was thinking iron sights for now, as the range I shot is 20metres... Do you guys think it's overkill for a PRS Gen 3 stock (if money was no issue).
 
I actually forgot about optics haha. I was thinking iron sights for now, as the range I shot is 20metres... Do you guys think it's overkill for a PRS Gen 3 stock (if money was no issue).

If you use "overkill if" and "money is no issue" in the same sentence, the answer will always be "do it".

The PRS adjustability is the selling factor here.

If you do get the PRS from the get go, you potentially won't have to change it later on when you move to more precise/longer shots.

It is also 'heavy' and close to your centre of mass, which will help for rifle/recoil control.

You can bias heavier items in the rear of the rifle, and lighten up the front as possible (Pencil barrel, Ti compensator, lightweight handguard, Ti adj gas block, Ti bcg, etc)

Of course this won't matter as much if you shoot from a bench and/or with a tripod
 
I note that as of yesterday there was a new IBI barrel assembly in the EE for $300. One could do worse.

OP - when I saw "Building an AR from scratch" in the title of your thread, I assumed that machine tools were going to be involved. Then I saw that you want to assemble a gun from parts.

Might be an idea to decide what you want the thing to look like, and to what use you are going to put it. Mirror commandos prefer short, highly accessorized pieces, suitable for viewing in a normal width mirror. Competitive riflemen prefer less adorned units with quality components selected for performance back to 500m or more.

I would like to buy some machining tools and have a little workshop. Maybe something for retirement. If you had 1,000 bucks to buy a barrel, which would you buy? I noticed through our Canadian stores, some barrels are mediocre compared to what I see through the USA-shops.
 
There is absolutely no reason to spend a grand on a barrel. It isn't necessary to throw money at any particular part. There is a multitude of quality parts available at cost effective prices.
The $300 IBI barrel I referenced has the barrel extension installed, along with the gas block and gas tube. Add a barrel nut and free floating handguard, and its ready to install on the upper. A plain tubular aluminum handguard and matching nut should be well under a hundred bucks.
 
The three most important parts, in this order.

Barrel
BCG
Trigger

Everything else is just personally preference and won’t make much of a difference in how it shoots.
You could argue that matching your buffer weights to your gas system and barrel length is equally important but to me that’s just doing your dilligence. You wouldn’t build a race car and then put motomaster tires from Cambodia tire on it. Also room for optic on that list, but not necessarily as important as the others.

One thing I’ll make mention as you mentioned it in your post. “Receiver fit” is a myth in terms of accuracy and reliability. If there’s a bit of play between the two it’ll function and shoot no better than if it’s a super snug fit and vice versa. Personal preference not considered.

Thanks, and I see some wedge options to tighten the wobble for the OCD types if that is an issue. A nice trigger from TriggerTech, the AR Diamond would be something I would look in to. Anyone have and or tried one of those trigger assemblies?
 
Thanks, and I see some wedge options to tighten the wobble for the OCD types if that is an issue. A nice trigger from TriggerTech, the AR Diamond would be something I would look in to. Anyone have and or tried one of those trigger assemblies?

Op, it may also help guiding you if you have a price ballpark for all this ;)

Some also like the 'path to excellence' approach when building an AR.

You start off with a generic/oem AR (like an M&P Sport 2). You get accustomed to it, then slowly change parts for 'better' (or more suited to you) ones, and you get to experience the difference :)
 
I note that as of yesterday there was a new IBI barrel assembly in the EE for $300. One could do worse.

^^^ that was quite possibly the EE deal of the week. I saw it but by the time I had a few minutes where I could reply it was (not surprisingly) gone :(

OP, keep your eyes open. Great things like this do pop up once in a while.
 
^^^ that was quite possibly the EE deal of the week. I saw it but by the time I had a few minutes where I could reply it was (not surprisingly) gone :(

OP, keep your eyes open. Great things like this do pop up once in a while.

That was indeed the DoTW for sure!

I remember seeing a p320 for 280$ (or was it 380$?) just because it had the small grip and some wear... missed it by a few minutes!
 
It isn't necessary to throw money at any particular part. There is a multitude of quality parts available at cost effective prices.
The $300 IBI barrel I referenced has the barrel extension installed, along with the gas block and gas tube. Add a barrel nut and free floating handguard, and its ready to install on the upper.


I'll check out the IBI barrel. I have about $3K that I allotted to this build, so my intent is to spend the entire $3K. Thanks to tharkhold, I might have to add another another grand or so for the Acog, as I forgot about that item.
 
Op, it may also help guiding you if you have a price ballpark for all this ;)

Some also like the 'path to excellence' approach when building an AR.

You start off with a generic/oem AR (like an M&P Sport 2). You get accustomed to it, then slowly change parts for 'better' (or more suited to you) ones, and you get to experience the difference :)


Thanks, just posted my budget. $3K, plus another $1K for optics.
 
I'll check out the IBI barrel. I have about $3K that I allotted to this build, so my intent is to spend the entire $3K. Thanks to tharkhold, I might have to add another another grand or so for the Acog, as I forgot about that item.

3k for the whole rifle (not including optics)?

wow... that should be a very, very, very nice rifle indeed! (Or just a very, very nice rifle with a BUTT TON of ammo! :) )
 
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