Basic accuracy question about ARs

[ForeverArmed]

Thanks for the additional responses, guys. (And good shooting there, AK103K!)

I was on AR15.com when I came across a post by a fellow called "Molon" which had pictures of groups fired from a 1/7, 5.56, chrome lined, Govt profile barrel. One 10-shot group was free floated barrel, optics, 75gr match ammo - the other was not free floated. Free floated results were 1.2" @ 100 yards. The non FF'd was 1.9" @ 100 yards. Remember, both with match ammo.

I believe I've hunted down that thread. Is this it?

http://www.ar15.com/forums/topic.html?b=3&f=118&t=279218&page=1

It's a long one but makes for some very enlightening reading. Of course I was already aware that 10-shot groups are better for determining statistical accuracy than 3-shot groups, but there's a lot of great info in that thread about different ammo types.

Indeed, as you just pointed out, the difference between a FF and non-FF barrel seems to be quite large. Here's what one of Molon's tests showed (from page 8 of the above thread):

All testing was done from a bench rest at 100 yards and consisted of firing 10-shot groups of hand-loaded 52 grain Sierra MatchKings. A Leupold Vari-X III set at 25X magnification was used during testing.

The three 10-shot groups used for evaluation of the free-floated barrel measured 1.06”, 1.42” and 1.47’. The three groups were over-layed on each other using RSI Shooting Lab software to obtain a 30-round composite group. The mean radius for this composite group measured 0.36”.

The three 10-shot groups obtained from the non-free-floated barrel measured 1.68”, 1.89” and 1.95”. The mean radius of the 30-round composite group from this barrel measured 0.56”. The difference of 0.20” in mean radius at 100 yards is equivalent to approximately 0.6” or 0.6 MOA.

If a non-FF is getting 1.5-2" @ 100 yards with from a rest with handloads, then maybe I'm getting about all I can out of the ammo I have.

Interestingly, I also found this on that thread (my emphasis in bold):

All shooting for this test was done at 100 yards from a bench rest. All groups consisted of ten shots each. For the first part of this test I decided to use the factory load of IMI M193. It is the most consistently accurate M193 load that I have come across. For the second part of the test I wanted to see how much I could improve on the accuracy of the IMI M193 load using hand-loaded 55 grain FMJ bullets. I choose to hand-load Hornady’s 55 grain FMJ-BT bullet for the same reason I used the IMI M193; it is the most accurate 55 grain FMJ bullet I have come across. The bases of these bullets appear to be much more uniform than the comparable bullet from other manufacturers. While I have obtained some singularly good groups using Hornday’s 55 grain bullet in the past, for some reason I have never created a 30-round composite group using this bullet.

Three 10-shot groups of the IMI M193 were fired from a free-floated 20” Colt HBAR with a 1:7” twist that is chrome lined and has a NATO chamber. (The Colt barrel was used because I’m just not willing to risk pressure issues by firing mil-spec M193 through one of my match chambered Krieger barrels.) Prior to obtaining those groups I fired a control load consisting of hand-loaded 77 grain Sierra MatchKings that measured 1.10”. The three groups of IMI M193 measured:

2.24”
2.59”
2.62”

That's from page 7 of the thread:

http://www.ar15.com/forums/topic.html?b=3&f=118&t=279218&page=7

Now if someone is getting around 2.5" groups with factory M193 from a free-floated barrel when shooting from a bench rest, then the chances of me doing much better from a semi-rested position seem somewhat remote. (As the above thread shows, much better results were obtained with handloads.)

I really am beginning to think the ammo is the main factor. I'm sure my technique is also a part of it, but I'm being as careful as possible when shooting these groups and, like I said in the first post, I'm not seeing much movement of the sight picture through the scope except for my heartbeat. And then there are the issues with the trigger, FF versus non-FF, etc.

One reason I'm concerned about the accuracy of my ARs that I want to be able to effectively gauge my own progress as a shooter. It's tough to decide what works and what doesn't when you aren't sure what your ammo and rifle are capable of.

Once again, thanks for all the replies!

 

[wcwhitey]

Good info. The best improvement I made on my DPMS Lo-Pro Classic (16" bull barrel) was to add the Hoque free float tube which came with their soft rubber grip. I may be a little off on the price but it cost me roughly $60 not counting the barrel nut wrench. Groups went from 2" @ 100 yards to 1 1/4" @ 100 yards. I then went from Federal surplus 55 gr. BT to Black Hills 52 Grain BTHP and the groups went to 1" or less. I have since developed a pet reload using the Sierra 53 gr match HP with either the Lake City or Winchester brass, WSR primer and W748 powder (26.0 grains). Groups are the same size as the Black Hills but I have cut the cost in half. I read at the time but cannot remember where that the BT's take longer to settle than regular spitzers and should be avoided for 100 yard (short range) shooting. I still say the gun has more in it as it still has the stock trigger and I haven't had the time to refine the load any further. Needless to say I am very happy with the gun and very impressed with the AR15 platform in general. It may take a little experimentation but the AR15's are capable of better than 2".

 

[TechBrute]

As most people have already said, a production AR with the standard trigger group and barrel is doing pretty well to get 2" groups. That's not to say you can't do better, but it's decent.

The first thing I would do is suggest trying different ammo. I would try the 62gr bullets with the 1:9 twist. I'd suggest Black Hills for excellent ammo, both red box (new) and blue box (reloaded).

I believe it was Jeff Cooper said that a trigger is less important when shooting from a bench. I tend to agree with that assessment. While an improved trigger is nice, it won't make the gun more accurate, it will make YOU more accurate. Typically, a match grade barrel and free floating will matter more to the gun's accuracy. I'd spend money on the gun, and then work on your trigger technique.

 

[rangerruck]

try winchester 45 grain varmints, also try the black hills, blue box, regular 55 grainers. then try as many diff makers as you can, eventually you will hit a round that is the 'sweet spot'.

 

[Powderman]

Good replies from all. However, I will once again nudge the already fallen apple cart...

The AR 15 can be EXTREMELY accurate, and usually is. However, in order to realize the true accuracy potential of the rifle, you MUST do one thing--repeat the EXACT point of aim, again and again.

One of the posters uses a low-powered scope, and from the posted picture, uses it extremely well. I will say that his experience in shooting that group shows a great amount of expertise with the AR15/M16--and it shows!

To replicate or surpass that group, you need two things. Either will improve the group; both will improve it dramatically. These are:

A highly visible, easily seen target with a definitive aiming point, and:

Excellent optics.

To see what I'm getting to, one need look no further than a benchrest rifle.

Now, I can hear the disagreement already piping up: "Hey, the AR is NOT a bench gun! It's a military rifle!!" This is true--but consider the salient points:

1. The bench gun has an action that has a repeatable, consistent lock up. So does the AR15 series of rifles. The rotary bolt system provides for a consistent shot-to-shot lock that is repeatable.

2. The bench gun has a well-tuned trigger. So can the AR.
3. The bench gun usually has a free floated barrel. Some enterprising souls bed the entire BARREL, and free float the action itself.

The AR15, in its normal configuration, has an "almost" free floating configuration; the only thing that affects the barrel harmonics is the gas block.

So, what can you do to enhance accuracy? Get something on the gun that will allow you to shoot repeatedly at the SAME point, over and over. And it goes without saying: the more you can aim at the EXACT point, the better your group will be.

To see just how good your rifle can be, put some good glass on it. I know; the best glass available for the bench gun will cost a whole LOT more than the rifle itself. A scope in the class of the Leupold fixed 36X or 45X; a Zeiss Diavari 6-24X, the Schmidt und Bender PM II 5-25, or the creme de la creme of precision optics, IMHO: a US Optics scope will buy you three or four completely tricked out AR15's, or even two completely built bench rifles!

However, there is good glass available for less money than the ones listed above.

Take a close look at the Nightforce line. The benchrest type scopes are available at decent prices; you will pay more for the side focus features of the NXS.

Nikon makes good glass, too--take a look at the Monarch line.

Take a close look at Burris optics, too--their new XTR scopes are hell for stout, made of all steel and made right here in America.

Redfield is coming back on line too, offering some really nice sounding optics with side focus capability.

Finally, for what I consider an excellent scope, look at the IOR Valdada scopes. Their glass is made by Schott Glasswerk of the former DDR-Deutsche Democratik Republik (aka East Germany)--original OEM suppliers for Schmidt und Bender and the older Zeiss scopes. I am saving up right now for one of their 9-36 eek: ) scopes--with a 37mm tube and 56mm objective, the light transmission should be fantastic!

Try it out! Put a high-magnification scope on your AR, and use a target like a benchrest 1-inch square at 100 yards. I think you'll be pleasantly surprised!

 

[Sniper X]

Oly arms here!

I have an Olympic arms PCR16 which with a tasco super varmenter mil dot set at 10X and using federal gold medal match ammo gets right at 1moa at 100M. But I shoot a lot. I also shoot this same gun in 3 gun matches.

 

[Lebben-B]

Put a high-magnification scope on your AR, and use a target like a benchrest 1-inch square at 100 yards. I think you'll be pleasantly surprised!

Your comments on optics presume good mechanics and set up on the part of the shooter. In ForeverArmed's first post, he states he gets a lot of judder and shake from using a 10x on his ARs. Imagine what it would be like at 24x.

After re-reading the thread, almost everybody that posted (myself included) offered a solution that had $$ attached to it. Allow me to offer this - a tight shot group begins with a tight set up. You are the firing platform for the system, therefore you must be as stable as possible in relation to the target. In your inital set up, look through the sights/scope. If you must move - even a little - to bring the sights onto the desired POI, your set-up is off. Back off the sights and re-set yourself.

Take a hard look at your breath control, too. Where is your pause - on an inhale or an exhale? How long is your pause? I find that shakes start 5-7 seconds after pausing and get progressively worse after that. Don't pause until you're 100% ready to fire.

Make sure you're relaxed when you shoot, using only enough muscle power to keep the rifle level and snug in the pocket of the shoulder. Don't put any preassure on yourself. Sure, we all want to shoot the smallest group we're capable of. But you don't have life or limb on the line if you don't make the shot, either. So relax and shoot.

Mike

 

[TechBrute]

try winchester 45 grain varmints, also try the black hills, blue box, regular 55 grainers. then try as many diff makers as you can, eventually you will hit a round that is the 'sweet spot'.

On the contrary. With a 1:9, you should shoot typically 55gr and up, not lower.

 

[Quintin Likely]

I've shot 52 gr SMKs out of a 1:8 with good results - won't know for sure how something works until you try.

 

[redneck2]

IMO, there is typically not a solution to accuracy. There are multiple parts of a large puzzle. Every piece you add gets you closer to the solution.

http://i41.photobucket.com/albums/e283/Indianaoutdoorsman/Gunpix-1.jpg

This is from a Bushmaster AR, 268 yards.

Match grade 24" air gauged barrel
Free float guard
2-stage match trigger
6.5x20 Leupold VX-III
Nosler bullets, WW cases, Federal BR primers
Solid bench
Sandbags front and rear
Good weather conditions

You probably won't do this with iron sights, on a windy day, or from a bench that has the very slightest wiggle

A "little" wiggle at the bench multiplies a ton at 100 yards

A little puff of breeze multiplies a ton at 100 yards

A rough trigger that jerks just a touch makes a ton of difference

There was an article in Handloader maybe a year or two ago that talked about accuracy. What it boiled down to was that bullets by far were the single most important determining factor as far as ammunition goes. Crap bullets = crap accuracy.

If you're sight picture is wobbling, then your rifle is wobbling (unless it's mirage on a hot day). How are you going to be accurate if you KNOW the rifle is wobbling? If your scope is cranked up and you can see movement, then you're moving. The solution isn't a lower power scope. The solution is a solid platform IMO.

 

[ForeverArmed]

Thanks for the further info, everyone.

I think it's pretty clear that the AR platform is capable of a hell of a lot better than 2 MOA groups. There are very high-end varmint rifles, like those made by Les Baer, that guarantee 1/2 MOA at 100 yards (using 5-shot groups).

I guess I was primarily wondering if 2-3" 10-shot groups were about par for a plain-Jane AR and non-match or surplus ammo. Based on the information people are posting and some further reading I've done (e.g., that AR-15 thread that Don't Tread On Me led me to and that I've linked above is VERY good reading for its info on ammo accuracy) the answer seems to be "yes." I suspect that 2 MOA is about the limit of the ammo I'm using (mil spec calls for better than about 3 MOA at 200 yards), and anything worse than that is probably due to my shooting (hopefully not a problem with my rifles).

I very much appreciate the suggestions regarding triggers, FF tubes, and so on, and I'll probably upgrade at least one of my ARs at some point. The 16" HBAR is a good candidate for some work anyway, since it lacks a flash suppressor.

Also, I've just ordered some Black Hills, so we'll see how that fares.

Excellent pointers on technique, too. Practice is something this long-time plinker, short-time target shooter can always benefit from.

Thanks again to each of you.

 

[TechBrute]

won't know for sure how something works until you try.

True, but the whole physics thing should give you an idea, though.

 

[Holtzman]

Don't lose sight

of the reason you have the guns. If you bought them for home defense, and they are within acceptable specs, you're golden. If you modify them for target shooting, you may be making changes that make them less suitable for home defense. Barrels with tighter tolerances will not feed as reliably as stock barrels, and heavy triggers will seem normal under stress. If you want a target rifle, go for it, the AR is a good platform, but don't obsess about fractions of an inch and make your self defense weapon less reliable.

 

[ForeverArmed]

I hate to revive a "dead thread," but here's a quick update. Yesterday I tried some Black Hills 50 gr V-Max in the 20" barreled AR and got a 5-shot group under 1" at 100 yards, with three bullets going into the same hole. Most of my groups with this ammo were 10 shots and were around 1.25 MOA. So it seems that the ammo was indeed a major factor, even if it wasn't the only one.

I have no doubt that a better trigger, FF tube, etc., would all help as well. But as Holtzman points out, this rifle was bought to be a potential weapon, not a target gun. I'll probably keep this rifle the way it is and save the upgrades for my next AR.

Once again, I appreciate all the advice on equipment, ammo, and technique. A lot of cool folks on this board.