Building an AR: Priorities in Accuracy?

J

jrucker2

Inactive
Hello, I am trying to build a quality AR on a budget, to fit somewhere in between the close quarters and DMR POU.

I want to know your opinions on priority of where I should invest my money to get the best bang for my buck accuracy wise? (and I'm looking for inside 200yrds, realistically I wont have many opportunities to shoot outside of that)

Here are the factors I am aware of in order by my current understanding:

1. Shooter
2. Ammo
3. optic/sights
4. trigger
5. Barrel
6. Freefloat
7. chamber
8. 16 vs 18 vs 20 inch barrel

Let me know what you think. Thank you.
 
You're the weakest link so shooter, then trigger and ammo together. Some ammo does or doesn't work but the trigger helps me a ton. I have a lot of ARs in different lengths and barrel styles and they're all very accurate. If I can be consistent and the trigger helps with that, then I just select the ammo that groups best. I also shoot better with a scope than with red dot or irons, but that's because our vision is the limiting factor and front sight posts and 5 moa dots cover a lot of the target at 100 and beyond. That's my experience and I hope it helps. 10x is plenty for me but I opt for higher so I don't have to tag along a spotting scope.
 
I'd say barrel then trigger. I have a standard trigger from PSA in the ar I built and for whatever reason it is drastically better than the m4a1, colt, and sig ar's I've used.

Buy a decent barrel and free float it, then drop in a trigger you can be consistent with
 
Ok so two votes for trigger. In regards to triggers, what are the price levels I'm looking at? I want something that is high value, doesn't mean cheap, but I don't want to spent 400 when 150 would be practically as good. So how much are we talkin? 100? 150? Also should I buy a cheap lower parts kit and the trigger seperate or are there trigger sets that include the lower parts as well?

Also, in reference to barrels. My understanding is that when you buy an upper that generally means chamber, barrel, gas block sometimes bolt carrier group. Is that true? As such when we same quality barrel is that almost the same as quality upper? (I understand you can build an upper yourself but it sounds like more effort than in interested in putting in)
 
I would suggest buying a fully assembled upper and just not worry about any of that.

The chamber is in the barrel it's not a separate piece unless perhaps you're thinking of the barrel extension which also typically comes pre installed. The gas block may or may not when you buy a barrel. If you buy an assembled upper it'll most likely be good to go. Sometimes they come with a BCG sometimes you buy it separate.

Take a look at Timney triggers and Chip Mccormick
 
a decent barrel is what is going to actually make the gun accurate. the trigger just helps you shoot it more accurate, but doesn't actually affect the accuracy at all. I would prob stick with an 18" if only shooting inside of 200 yards. a decent ALG trigger will run you a bill and help you do your part. an accurate rifle will have a nice tight barrel, free floated and a tight fitting upper to lower receiver and a solid stock. a fixed stock will be more accurate if your okay with that.
 
I would say that the barrel is much more important for accuracy than the trigger, mechanically speaking. That being said, a nice trigger will make a gun easier to shoot, but it won't make the gun itself more accurate. I personally hate shooting guns with heavy and vague triggers, so I invested in the SSA-E from Geissele and I absolutely love it.
 
For the rifle:

1. Barrel; groove diameter .0005" smaller than bullet diameter, uniform twist rate and slowest that'll stabilize bullets used, hand lapped to +/-.0001" bore/groove diameters. Stainless, cut rifled ones seem to be the best.

2. Free float the barrel and lap bolt lugs to full contact.

3. Chamber; SAAMI spec is fine, but back end (bolt face) must be square with chamber axis.

4. Bullet; match quality, well made and balanced, .0005" bigger in diameter than the barrel's groove diameter.

5. Powder; extruded powder, not ball powder.

6. Primer; uniform in output, hit with pin driven by spring at or 10% above factory spec.

Barrel length has little to do with accuracy; sight radius does a little if using irons. Good triggers, scopes and marksmen only make it easier to shoot the rifle accurately; any one that's the best will be masked by the worst of all the others. The six above have to be in place to see any issues with these.
 
In terms of accuracy that is built into the rifle, what follows is my advice based on High Power Service Rifle AR-15s. I may have put together a few of them...

There are four main parts to consider on the rifle for accuracy, and I've listed them in what I consider most to least important. Then I will cover sights...

Barrel. The barrel is the only part of the rifle that touches the actual bullet, so it is the only part of the rifle that is imparting accuracy. Between 16, 18, and 20" barrels you probably want an 18 or 20 as you can use a rifle length gas system with those which helps with reliability. It sounds like a 1:8 twist is what you should be looking for since most match grade barrels come with that twist.

Free Float Tube, this part only exists to minimize how much shooter inconsistencies affect the barrel which affects the bullet. NM free float tubes cost more than simpler designs, but they all do the same function.

Trigger. The better a trigger the easier it is for the shooter to be accurate. Get a G2S, SSA, or ACT trigger depending on your price point. If you aren't limited to the 4.5 lb trigger pull weight for Service Rifle that opens up other options. But a DMR style rifle will have a milspec trigger pull.

Stock. A standard A2 style stock is all you need for excellent accuracy. Other stocks cost a lot more, like a Magpul PRS, and while they make it more comfortable, it doesn't necessarily make the rifle more accurate just easier to shoot accurately for some shooters.

Sights.... If you use a scope it is easier to aim precisely. If you use iron sights it is more difficult to aim precisely. However, you can't tell on the target whether a tight group was shot by scope or irons. But the sights have nothing to do with the mechanical accuracy potential of the rifle, only with how well YOU can precisely aim the rifle with repeatability.

Everything else is not an issue with the rifle. Obviously use the best ammunition you can buy or load, and get as much trigger time as you can.

Good luck.
 
Ok thank you for the advice. So my plan is to spend my money on the upper and to make sure it's free floated. Next I will invest in a quality optic and finally get a better trigger.

I don't want a fixed stock, 20 inch barrel or rifle length gas system as I want a little more versatility. As such do I gain that much more accuracy moving from a 16 to an 18 inch barrel? I know it's about 100fps, but is the increased velocity and possibly accuracy worth the extra weight and size when it comes down to it?
 
what about the relationship between the upper and lower, should it be a tight fit, snug, some wiggle or doesn't matter?
 
Barrel length has nothing to do with accuracy.

The .223 Rem has about 25 fps velocity change for each inch of barrel length; higher when longer, lower when shorter. Comparison's only realistically made when cutting off a long barrel in 1" increments. It's a waste of time to compare two barrels as one won't have the same bore, groove and chamber dimensions as the other one; enough to show a 50 fps or more difference for the same length.
 
I don't want a fixed stock, 20 inch barrel or rifle length gas system as I want a little more versatility.
Click to expand...

Sounds like you don't really want accuracy.

If you absolutely must have a non fixed stock, there is only one collapsible stock that I can recommend for accuracy, and that is the Magpul UBR. Unfortunately those aren't cheap.

Jimro
 
Barrel and trigger are most important. I shoot "F" 1,000 yards with my bolt guns, you can only do that with a quality barrel in the $350 to $450 dollar range. I'm partial to Krieger heavy match barrels in my bolt guns with 8oz triggers. I'm in the process of building my second AR in a year. The first one was a carbine; collapsible stock, 16" ultra light VooDoo barrel, carbon fiber FF forearm, and Jard adjustable 1.75 pound match trigger -$155.00. My current build has a collapsible stock, carbon fiber FF forearm, Jard adjustable 2 pound match trigger -$155.00. I'm waiting on a Black Hole Weaponry SS 20" mid length standard weight barrel. This will be a hunting and 300 to 600 yard target rifle.

You can order the top adjust trigger direct from Jard with the weight spring you want fully adjustable. This will be my third AR with a Jard trigger.

This will be my first Black Hole Weaponry barrel, I'm looking forward to it. They custom make their barrels with polygonal rifling- individually made to your specs: barrel length, weight, about a dozen or more different types of fluting and finishes, and a whole range of AR wildcat calibers. If you join their forum first before ordering a barrel you'll get a 10% discount. I actually joined after I had ordered my barrel and they refunded me the 10% discount. Also they offer special sales during the year, Shot Show, Black Friday and etc, where offer another 10% discount on their barrel prices.
 
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I don't want a fixed stock, 20 inch barrel or rifle length gas system as I want a little more versatility.
Sounds like you don't really want accuracy.

If you absolutely must have a non fixed stock, there is only one collapsible stock that I can recommend for accuracy, and that is the Magpul UBR. Unfortunately those aren't cheap.

Jimro
Click to expand...

Yes that is true. As I stated in my original post, I want something versatile. But I would like to increase the accuracy where possible without loosing too much maneuverability. I also mentioned that the farthest I was interest in shooting was 200 yards. That being said, I'm probably not going to regularly invest in match grade ammo.

As such this whole discussion may be moot. But that's why in asking: inside 200 shooting remington white box, federal and the like will free floating, using a stainless barel and a good trigger make a noticeable difference? Also that being said I definitely don't want a super super light 1 lb or 8oz trigger. Again versatile but trying to spend my money In the best place to gain accuracy. Additionally may I add that at the end of the day I don't want to be too much north of 1000-1200 optic excluded.
 
jrucker2,

Your first post made it sound like you were looking for something like a Mk11 DMR rifle, compact and accurate.

If you aren't going to spend the money on good ammo, no point spending the money on a match grade barrel. Get a 1:9 chrome lined or nitrided whatever brand is cheap, put it in a two piece aluminum free float tube (whatever's cheap, brand doen't really matter if you loctite the sucker in place), get the ACT trigger and call it good. If you have the money for a UBR stock, it would be money well spent.

Will it shoot good? Who knows. You might end up with something that is 3 MOA or 1 MOA with cheap ammo.

Jimro
 
When you say 200 yd AR, IMO, your priorities should be:

1) optics - 200 yd max....depending on your tastes, that might be a red dot, 1-4x, 2-8x, 3-9x or maybe 4-12x...

2) trigger - I would spend $100-$200 on a good 2 stage trigger.

3) barrel - this is where accuracy can turn from good to great.
 
I think I get what you're after and that's why, for shooting 200 yards, being consistent and a good trigger and ammo that works is what I think will work. I have 'junk' barrels that aren't free floated with good triggers and they'll shoot an inch with some factory ammo at 100. In no way would I consider them target rifles or exceedingly accurate. I totally agree with the others that the barrel is the accuracy but I don't think that's what you're after, 800 yard, sub moa gun.
 
Also, if you won't make or buy match ammo, I would not bother with a barrel over $250.

A great barrel/upper can be had, but you are looking at ~$900 for the Uppr + matched BCG.

Also, weight is accuracy....low weight = low accuracy.

So, why don't we start over with these 3 questions:
1) what is your definition of accurate at 200 yards?
2) what does versatile mean to you?
3) what efforts will you be making regarding ammo and training to make this happen.

For me:
1) I want to lay rounds on a 10" 300 U.S. gong with ease.
2) it means carries on 2pt sling....about 10 lbs max...18" barrel
3) I will make near match reloads on my progressive press for this chamber/barrel

So, I have a home built AR with a chopped Armalite A2 barrel 18.5" with FH. Trigger is ADCO improved RRA 2 stage, a VLTOR stock and a Nikon Monarch 2-8x BDC scope.

I can quickly and easily engage at 300 yds. Possibly 600 yds with a bit more time.
 
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