What components take priority on AR build?

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beeenbag

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I have built several ARs and tend to use good but budget parts. I know you don’t skimp on the BCG, the barrel and if a good trigger is desired few parts kits contain “good” ones.

My question is, how important is say, the manufacturer of the stripped upper? The gas block? Items like that.

So in a list of priority, where would you be sure to allocate most of your funds on a build?
 
Stripped recievers don't matter a hoot unless you want some superfluous features specific to one or the other manufacturer.

Muzzle devices, gas blocks and charging handles are all fairly hard to mess up. Sure, there's OBJECTIVELY better parts out there for high prices, but there's plenty of "good enough" parts at almost give away prices. "Take-off" parts like A2 muzzle breaks, basic charging handles, gas blocks/front sight bases can frequently be found free or next to it on local pages.

I'll get picky about barrels and BCG's. I like a nice trigger but depending on the particular AR in question, it isn't a necessity for me.
 
Barrel. Bolt. Springs. Buffer. Sights. Proper assembly.

The barrel and the bolt are the core of the AR. Barrel quality affect precision. Gas port diameter affects reliability. Chamber affects both. Bolt quality affects durability. Extractor, ejector & springs for both affect reliability.

Springs affect reliability. Don't cheap out on springs.

Many ARs come with a CAR buffer. Car buffers are too light. ARs should use an H, H2, A5H2 or rifle buffer and the appropriate receiver extension.

Sights affect shootability. If you can't see it, you can't hit it. Without good sights, the shooter can't make use of the precision the AR has to offer. a 4 MOA AR with good sights is better than a .4 MOA AR with poor sights.

Can't say enough about the proper assembly of an AR. It could be made up of the best parts on the market, but if it isn't properly assembled, it won't be precise, reliable or shootable.

Triggers can be important, but I'd address the other stuff before spending money on a trigger. Doing a clean and lube and a bit of dry fire can go a long way to improve a standard AR trigger.
 
If it's meant to be a hard use rifle with higher round counts, I wouldn't overlook a quality gas black with strong attachment method. Probably not something you want to try to fix in the field should it rotate/move or otherwise mess up.
 
Barrel, bcg, sights.
Trigger is right behind the barrel in priority to me but I’ve never spend money on a fancy one... just lots of time adjusting , filing and polishing whatever milspec came with my parts kit. As long as the metal is hard I can make a decent trigger out of it.
 
Barrel, BCG, trigger, and good optics. My most accurate AR uses a Black Hole Weaponry barrel, Toolcraft BCG, Rock River Varmint 2 stage trigger, and Primary Arms 4-14x44 FFP scope.

I really like Aim Sports free float tubes. They’re around $60, and really good quality. Primary Arms scopes have glass as good as some costing 3 times more.
 
Barrel: correct gas port diameter and location, crown, proper chamber dimensions (decision depends on purpose of rifle)

Bolt: extractor, springs, metallurgy, inspections

Upper Receiver: lap the face for proper barrel lug alignment for reliability and longevity of bolt lugs and chamber

Trigger: depends on use of rifle

Buffer and springs: depends on gas location and purpose for rifle

Gas block: depends on use of rifle
 
Barrel, BCG, Trigger. Gas block effects reliability, but a good reliable clamp-on isn't terribly expensive. Optics? Not really part of the gun, but an area where you definitely get what you pay for.
 
For me it's:

Barrel
BCG
Trigger

In that order, and I really, really, look at intended usage when selecting those parts. Then I get into gas block, FF forearm, muzzle device and the rest based on task/purpose. I generally go with an upper and lower based on what's on sale. Lately I've been using Aero's.
 
I shoot my AR for multi gun mostly.

For me I make sure I have good:
Trigger
Bcg
Optic

Things that need to be decent are:
Barrel
Safety
Buffer system (I don't like twang)

Things I have preferences for but not critical:
Grip
Stock
Forend
ETA: muzzle device

Things I take for granted:
Gas block/tube
Springs
Trigger guard
 
The barrel and bolt are the heart of the rifle. If those parts are bad, it won't matter how good the rest of it is.

But really it depends on intended use.

I examined the barrel of my 3-gun rifle with a bore scope a while back. It looks like a dry lake bed. Flame cracking, erosion. It looks nasty. Still shoots about 2 MOA with factory 55gr ammo. If you want to shoot tiny groups, it usually pays to buy a premium barrel. You MIGHT get a cheap barrel that shoots well. But it is a roll of the dice.

It is important to understand how all the parts work together in concert.

Buffer weight, and spring rate of the buffer are variables that may need to be changed. Adjustable gas blocks ad another dimension of being able to tune the rifle to operate optimally with a given ammunition or a variety of ammunition.

At some level of pursuing accuracy, the upper receiver does indeed become important.

Of course the trigger is the final interface between the shooter and the bullet as it is sent to the target. All of my rifles are equipped with match grade triggers and I wouldn't have it any other way.

This build for PRS Gas Gun matches utilizes a Mega Machine monolithic upper receiver. JP low mass carrier and silent captive spring. Jp adjustable gas block. JP tank brake. Larue Stealth 20" barrel. Magpul UBR stock. And a JP single stage match trigger.

9KGv51Q.jpg

KmuLs4Q.jpg
 
No matter what you are building your AR for there are three things you need to worry about.
BCG
Barrel
Trigger
I have no set as to which is more important, that will depend on what the build is for.

If you'er going for accuracy it would be;
Barrel
Trigger
BCG
825B3D6B-8006-48F3-8B13-3F6B035B4522.jpeg
9203C6E6-944B-4596-94D3-0DDCD6F94E73.jpeg

If it's a training gun where you will have a high round count;
BCG
Barrel
Trigger
196728CA-96A8-44CB-AF58-E6D67F49E47C.jpeg


For a duty gun
Barrel
Trigger
BCG
C2FF8A93-DBA5-4705-8A5A-B155D0BC97D2.jpeg

Now there are a lot of other parts that others will say are important like springs, gas ports and charging handles, but they are all important, just some not as important as others.
I guy brought me an AR that was shooting way high. I removed the barrel and lapped the face of the upper receiver. He later told me that the rifle was shooting great and he could now use his iron sights.
 
A great trigger won’t make a poor barrel more accurate. So I list the barrel as most influential to the rifle’s raw potential.

Everything else is really about the shooter’s influence on the rifle, not the rifle’s influence on the bullet. Clamshell handguards, bad triggers, wobbly stocks, and poor sights/optics will make the shooter more likely to screw up a shot, even despite a good and capable barrel.

I’ve never had to look very hard to get a quality bolt and BCG, but I also have never really compromised or had any desire to mess around with low quality BCG’s and bolts anyway.

Various carrier weights, buffer weights, buffer spring rates and types, gas system lengths, and gas block types are really nothing more than reliability tuning and cycle balancing. There’s no magic to it - the mass should be enough to keep the bolt locked until sufficiently after the pressure spike to avoid excessive base expansion.

Any AR I build for myself (not restricted by competition rules) typically includes all of the aspects I recommend for others who are looking for anything but a cheap blasting machine: Match grade barrel, upgraded trigger, free float handguard, adjustable gas block, quality M16 BCG and bolt, and H2 buffer. These things pile into a small shooting rifle with perfect reliability and great shootability.
 
My question is, how important is say, the manufacturer of the stripped upper? The gas block? Items like that.

I think others have alluded to it mattering, as in Gunny’s post about having to lap to correct POI, and I recall from reading that several like Varminterror always lap which means no matter who’s upper you go with, you will still need the correct tools to finish it up right (what MistWolf describes as “proper assembly”).

If I were giving advice, being seasoned yet oh so very green on the subject of ARs then this would be my approach:

1. Select the rifle’s purpose. No sense in building it just to have, know how you’ll use it, and there are no wrong answers here.

2. Determine the budget necessary, repeat necessary, to satisfactorily meet your objective. Thinking you want a precision AR on a $450 budget is a dream not mesh-able with reality. If your budget won’t allow for what you want, save more or build for a different purpose that also suits you.

3. Whatever you do always consider this question: which piece, from the .30 cent pivot detent to the $20 selector switch are you fine with failure from? If you don’t want to live without a magazine catch or a stock then there aren’t many non-critical parts to cheap out on.

There are definitely priority 1 parts to spend more on, but I wouldn’t count many of the remaining that I’d go too cheap on. Apart from those already listed I really like an oversized bolt release and a large latch charging handle for purely ergonomic reasons, as well as a comfortable stock.
 
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The barrel.
Get the barrel you want first, the rest of the rifle you can get anywhere, anytime. Get a
top notch barrel. IMO nothing influences the rifle's accuracy like the barrel.
 
No matter what you are building your AR for there are three things you need to worry about.
BCG
Barrel
Trigger
I have no set as to which is more important, that will depend on what the build is for.

If you'er going for accuracy it would be;
Barrel
Trigger
BCG
View attachment 846030
View attachment 846033

If it's a training gun where you will have a high round count;
BCG
Barrel
Trigger
View attachment 846034


For a duty gun
Barrel
Trigger
BCG
View attachment 846035

Now there are a lot of other parts that others will say are important like springs, gas ports and charging handles, but they are all important, just some not as important as others.
I guy brought me an AR that was shooting way high. I removed the barrel and lapped the face of the upper receiver. He later told me that the rifle was shooting great and he could now use his iron sights.
Glad to hear you lap the front of the upper receiver. A number of folks have doubted me on that....I really don't care what they think, it helps, no doubt in my mind.

Russellc
 
I recall from reading that several like Varminterror always lap

I do lap my receivers - first to eliminate high spots, but secondly to let me pick 45-50ftlb torque. So I lap once to clean up, check my torque at alignment (if using a barrel nut which requires it - many do not of late), and if I need to lap more to get lined up at 45-50ftlbs, I lap a bit more to get there. Most of the rifles I put together are sub-moa hunting or target shooting rifles, but even for a duty type rifle, I prefer my receivers to be flush with even contact. No high points to warp or walk.

It might be a lost art, but I also shim my barrels if they aren’t a tight slip fit or interference fit. I don’t glue barrels into my uppers any more (only rarely), but I do want a tight fit.
 
I do lap my receivers - first to eliminate high spots, but secondly to let me pick 45-50ftlb torque. So I lap once to clean up, check my torque at alignment (if using a barrel nut which requires it - many do not of late), and if I need to lap more to get lined up at 45-50ftlbs, I lap a bit more to get there. Most of the rifles I put together are sub-moa hunting or target shooting rifles, but even for a duty type rifle, I prefer my receivers to be flush with even contact. No high points to warp or walk.

It might be a lost art, but I also shim my barrels if they aren’t a tight slip fit or interference fit. I don’t glue barrels into my uppers any more (only rarely), but I do want a tight fit.


I have taken to using loctite bearing sleeve retaining compound.
 
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