ar-10 accuracy, what is to be expected from a factory upper?

[georgehwbush]

just bought my first at-10 and was wondering if i could expect anywhere close to the same accuracy from this gas gun as i get from a factory bolt gun of like caliber.

i have been shooting a savage 243win for several years now. just sold it and bought a new ar-10 in 243win, havent had time to work up a load yet. but was hoping that it would be somewhere close to the same. is that just wishful thinking ?

[DubC-Hicks]

It completely depends on brand, barrel, and ammo. My factory built Saint Victor 308 is a 16" and I'm lucky to squeeze 2 MOA out of it with Federal GMM 168s, but the 308 I built using a not fancy at all Ballistic Advantage 20" nitrided heavy barrel will do 3/4 MOA with the same ammo.

[georgehwbush]

so basicly you are saying that sub MoA should not be unreachable with a 24" SS 1:8 sporter and hand loads in the 100 to 115 grain range ? yes ?

that is what i was "hope'n for" when i bought it.

and thank you for your response. btw

[stagpanther]

My personal opinion is that you can get exceptional accuracy out of an AR (10 or otherwise) but compared to a bolt gun there is a lot more going on getting a cartridge from the magazine to the chamber (and the case back out)--in other words there are more mechanical and gas operations that need to be optimally tuned when compared to the simplicity of a bolt gun. AR's can also have limitations imposed on the cartridge OAL by the magazine, which may prevent optimal seating of the bullet relative to distance to the lands. My rule of thumb for my personal ARs is if it gets 1 to 1.5 MOA @ 100 or more yds that is acceptable and "solid" performance, especially if it gets it with a variety of types of ammo. If it get sub MOA once I find a load it "likes" that's very good; if it can get close to .5 or less MOA fairly consistently with a good load that's exceptional. but that's just my opinion based on my skill level.

[DubC-Hicks]

you are saying that sub MoA should not be unreachable with a 24" SS 1:8 sporter and hand loads in the 100 to 115 grain range

Sub MOA is definitely possible with the right setup. But just saying 24" SS 1:8 sporter barrel doesn't mean much of anything at all. There are plenty of quality SS barrels out there that are excellent, and there are plenty of budget or no name SS barrels out there that shoot very poorly. If your barrel is from a well regarded company, I think you'll be happy with the results.

[MTT TL]

It's kind of like asking; "what kind of gas mileage can I get out of my truck?"

[rickyrick]

In general, semiautomatic rifles are not as accurate as their bolt action counterparts.
ARs seem to be the exception at times.

[georgehwbush]

thank you to all the replies; and that kinda confirms what i thought i knew already.

it is a budget gun, but the savage axis was too. so with all that has been said, i will push for sub-MoA but not whine too loud if i can't get that out of it.

i ran some cheep factery ammo through it, about 50 rounds of fed 100sp just doing a break-in. and bringing the scope to "close enough" to zero. i did change the gas block to an adjustable one. i kinda knew that would have to be done to get hand loads to cycle acceptably. it did come with a nice polished trigger. about 2.5/3.0 pounds, a little heaver than i like but it is an ar platform...

at any rate wish me luck and if i get it working well i'll post info and pics. if not i'll probably be back with questions <

thanks again to one and all.

[603Country]

Couple of years ago I bought an expensive AR (in 223). I worked up a zillion handload combinations and the dang thing was a 1 1/2” shooter. Finally I called the company and was told that the rifle was guaranteed to meet Milspec accuracy. Well, it did do that, but I wanted better. A new barrel solved the problem.

[jetinteriorguy]

My AR10 in 6.5CM is a solid MOA shooter with my handloads. It’s a real keeper even though not a sub MOA, mainly because no matter if the barrel is hot or cold it keeps MOA with only a slight 1/4” shift in POI.

[MarkCO]

It depends on a lot of factors.

First is build quality. Do you have a tight fitting barrel extension to upper fit, or was it properly thermofit? Is the gas system dwell proper? Is it overgassed? Is it properly twisted? Is the barrel properly settled (same with a bolt gun). Second is the shooter. Do you have great fundamentals and a NPoA that is unaffected by the 4 recoil impulses (as opposed to one of the bolt gun). Third, do you have a good load that is matched to the twist rate and barrel length/gas system.

Most people get happy with 2 MOA from an AR pattern .308. Very few bother to, or even know how to, tune the variables for the best results (accuracy and precision) of a large pattern AR. Most of it is poor shooting fundamentals and over gassed systems. I'll be direct, I'm not happy until I can get under 1 MOA. Some of my Large frame ARs I just could not get better than 1 MOA, and some have dipped well below that. My current Large frame is STAG based, but neither upper, in 6.5CM and .308Win have Stag barrels because they won't deliver the accuracy I desire. They both produced 1 MOA out of the gate, before they were settled and without any specific load development.

What is interesting to me with these two current uppers is that every load throws the last round (at locking open) low and right, and I am still 1 MOA. When (and if) I get that fixed and tune a load, these have the potential to be under 1/2 MOA for sure.

[Double Naught Spy]

so basicly you are saying that sub MoA should not be unreachable with a 24" SS 1:8 sporter and hand loads in the 100 to 115 grain range ? yes ?

As noted above, there are other factors involved, but concerning the barrel, that is hypothetically correct, though the barrel's length and being SS really doesn't matter. The reality is that if you get a garbage barrel, you may never be able to find a load for it that works very well (worst case scenario).

[stagpanther]

just bought my first at-10 and was wondering if i could expect anywhere close to the same accuracy from this gas gun as i get from a factory bolt gun of like caliber.

i have been shooting a savage 243win for several years now. just sold it and bought a new ar-10 in 243win, havent had time to work up a load yet. but was hoping that it would be somewhere close to the same. is that just wishful thinking ?

Just shoot it and prepare to tune for optimal loads--nobody can definitively say what you should expect nor should you be predisposed to exceptional or abysmal performance.

[mehavey]

Don't know about 243, but Ruger's "AR-10" in standard 308Win is good for ¾ MOA.
https://i.postimg.cc/PrrjjNxk/Ruger-...Match-Load.jpg

[USAF Ret]

Originally Posted by jetinteriorguy

My AR10 in 6.5CM is a solid MOA shooter with my handloads. It’s a real keeper even though not a sub MOA, mainly because no matter if the barrel is hot or cold it keeps MOA with only a slight 1/4” shift in POI.

Jet, is it a custom or factory build? What is you barrel length and weight? Asking for a friend who might want to have a 10 in 6.5 CM. :-)

[MarkCO]

Originally Posted by USAF Ret

Jet, is it a custom or factory build? What is you barrel length and weight? Asking for a friend who might want to have a 10 in 6.5 CM. :-)

Not Jet, but I'll relay my experience with Large frames and barrel length...

If you use an extended gas system +2 over rifle length, you can get away with a 25" in 6 and 6.5mm barrel if tuned well and using a proper powder. With .308, more like 23". Rifle length gas systems, 20 to 22" is the sweet spot for 6mm and 6.5mm respectively. Mine is a Seekins 22" for 6.5CM and 18" for .308, both rifle gas.

I've built a good number, for others and myself in a lot of calibers, and for precision at least, the longer gas systems just work so much better. A lower pressure helps mitigate the movement for that 2nd and 3rd recoil impulse. My .308, I have been able to put 5 rounds on a 10" plate at 550 yards in 5 seconds. That is not something one needs to be able to do, but it is something not possible with most .308 pattern ARs set up "typically." I can even free recoil my .308 into the same plate at 550 yards for 1 shot, again, very non-typical.

[georgehwbush]

thanks to all for replying to my post.

i have another thought i would like to express. being kinda new to all this.

what should one watch for as far as gas-block adjustment ?

when i am ready to open the gas block, i know that it needs enough to make it cycle.


But that's really all i know. any thoughts would be welcome.

even the "get out of here dumb arz, and let the experts do their job" welcome on that one.

for what or where should i be looking?

[MTT TL]

My AR-10s aren't as finicky as 5.56, which really isn't that picky unless you get into short barrels and go suppressed. I guess what I am saying is that I've never had to adjust my gas block and seldom, if ever have cycling problems with all kinds of ammo.

An SBR/ subsonic 308 is kind of clown shoes. It makes no sense as the case is so large, you might as well just get a 300BO or similar. So I'm not sure where you would need to adjust the gas block.

[tangolima]

Mine in .243 win hovers around 1moa. It was put together with parts as cheap as I could find. The scope could be the only exception, but even that has nothing to brag about. Have spent time to tinker it though.

Will switch to better bullet. Currently loading with the cheapest 75gr speer varmint bullets. It goes fast but also loses speed fast. It goes transonic right after 500yd. As sensitive to cross wind as 5.56. 100gr spbt should do better.

-TL

Sent from my SM-N960U using Tapatalk

[stagpanther]

what should one watch for as far as gas-block adjustment ?

I would recommend simply going onto adjustable block manufacturer's sites (or UT) and learn how they actually work. But knowing how they work is only part of the picture, you will need to understand the sequence of firing, building up peak pressure behind the bullet, how long that pressure remains behind the bullet before and after it passes the gas port and when it dumps after bullet exits the muzzle. This determines dwell timing (which MarkCO indirectly alluded to above), which effects when the gas impulse coming from the gas tube unlocks the bolt and sends the carrier back to eject the spent case and cycle the next cartridge. Upon firing the brass case expands to the walls of the chamber and takes a bit of time (milleseconds) to snap back and relax, if the impulse from the tube comes to soon or strong it might/probably cause extraction issues or even damage the rim and leave the case in the chamber or only partially cycled. Not every barrel has the same port size even if its the same length and cartridge--which is a probably why adjustable blocks were invented to begin with, but in general most barrels were and still are mostly made in an overgassed configuration to enhance reliability in a wide range of ammo. AR 10's have the additional issue--if you're building one with parts from different manufacturers, that there is not the same kind of standardization that you'll typically find in most AR15's--though in general most parts come close to conforming to the "DPMS" standard or LR 308. But even a few thousandths of an inch difference can create monumental headaches--they have for me.

[MarkCO]

Originally Posted by georgehwbush

what should one watch for as far as gas-block adjustment ?

stagpanther probably answered as best as can be done without one actually being their looking at the rifle, knowing the load, etc.

Almost all Large frame ARs are significantly overgassed. The shorter the gas system in relation to barrel length, the worse it is.

Checking brass rims and even case bodies for extraction issues is first. How far the cases get thrown is next, but that is as much the ejector as the bolt carrier velocity.

[jetinteriorguy]

Originally Posted by USAF Ret

Jet, is it a custom or factory build? What is you barrel length and weight? Asking for a friend who might want to have a 10 in 6.5 CM. :-)

It’s a stainless heavy profile barrel with an adjustable gas block from PSA. I bought it as a full built rifle other than adding a Geissele two stage trigger and a muzzles brake, been a few years and I can’t remember what brand muzzle brake it is.

[georgehwbush]

i ran a ladder test today, got 0.930" 5 shot group with only three holes in the paper, out of 43grs. of reloader-19 : but was starting to see preasure signs. so i'll back that down just a little. not bad speed either, avg. 2928 with sd 24. yes the sd is a little high but i'm not done either.


anyway, just wanted to update the post, and say thanks again.

[Shadow9mm]

Originally Posted by georgehwbush

i ran a ladder test today, got 0.930" 5 shot group with only three holes in the paper, out of 43grs. of reloader-19 : but was starting to see preasure signs. so i'll back that down just a little. not bad speed either, avg. 2928 with sd 24. yes the sd is a little high but i'm not done either.


anyway, just wanted to update the post, and say thanks again.

Don't forget to keep things in perspective. In all honesty a SD of 24 is pretty good and will beat most factory ammo and some match ammo. Last testing I did was with 6mm arc and Hornady match ammo, SD of 22, ES of 83. While you may want, and even be able to get, better SD numbers, 24 is nothing to scoff at.

[stagpanther]

You should both try single-feed hand loading into the chamber --you'll see those numbers drop and better accuracy more than likely. But no autofeed.