Rifle accuracy question.

[wanderinwalker]

One of the primary reasons semi-autos are not as accurate as bolt action guns is that there must be some tolerance allowed for cartridges to seat and fire repeatedly. It is true that modern semi-autos have that tolerance down to a minimum but it still isn't going to be as tight as a bolt action gun. An important part of choosing the right ammo for target shooting is getting cartridges that are almost exactly perfect for your particular chamber. Even a tiny amount of variation can make for a wider pattern down range. The trigonometry of the situation could easily demonstrate how a cartridge that is loose even 1/100th of an inch can measure an inch and a half inch off at 100 yards assuming a 24" barrel. My trig is hastily done here but the principle is sound. Even a small amount of tolerance can result in a sizable increase in group size at 100 yards. I'm not an expert on tolerances by any means but I do know I've heard many people discuss these things. Plus even things as precise as the timing of the firing pin on the round (is the round set when it gets struck by the pin) can spell a major amount of variation at 00 yards.

But 1/100 of an inch is measured at .010". That's horribly loose tolerances in ammunition and probably won't even chamber in most chambers. Most match shooters talk about getting tolerance down to .001", and I've heard suggestions that even as much as .003" of run-out on a loaded round is barely noticeable downrange from a shoulder-fired rifle.

Let me also add I don't think in terms of absolute precision in the way a benchrest (or a bench-centered) shooter thinks of it. I'm a position shooter (NRA Highpower and now Smallbore) and I can't think of the rifle without putting the shooter into the system. So I don't care what steps can be taken to make a rifle shoot 1/10" tighter at 100-yards because I know from experience without mechanical aids few shooters can hold well enough to take advantage of much more than about a 3/4 to 1-MOA rifle.

I shoot an AR in Service Rifle competition, and to 600 yards I don't see the gas guns shooting groups 3x the size of the bolt guns. The bolt guns can shoot tighter, but a well built AR with a good barrel (I'm thinking of a couple of match rifle shooters I know) will shoot perfect scores against a 2-MOA target at 600 yards prone, with lots of Xs (hits in the 1-MOA center).

With either action design the path to accuracy seems to be a good barrel and free-float. On an AR that's about it; with a bolt gun you can true and pillar bed the action. And as much as I love shooting my AR-15, I will not deny that a bolt action is a better choice for a bench-rest rifle or a pure long-range rifle. Yet within 300-yards without mechanical rests, I think the difference in accuracy is a wash for most shooters.

And I want to say, my feeling is that highpowered scopes, ultra-light triggers and super-fast lock times are purely for the shooter. They won't make the RIFLE shoot any more accurately; rather they make it easier to shoot the rifle accurately.

 

[Tirod]

It's not the gas action as much as it's the barrel extension. Compare the two: a bolt gun has the barrel screwed into a heavy receiver, and the bolt locks into it, usually with two heavy lugs that have to rotate 90 degrees.

AR? The barrel extension is screwed directly onto the barrel, and the bolt locks into that, not a long heavy receiver that also acts as the stock attachment. You can fire an AR barrel by locking the bolt only into the barrel extension. The bolt has mutiple lugs and only needs about 30 degrees to unlock.

The AR package means the barrel extension is short, and therefore inherently stiffer, with multiple lugs, it's inherently more square and coaxial to the centerline, and because of the methods of machining and attachment, inherently more accurate. Most of the parts are CNC formed from stock, not cast or forged. That leaves the upper and lower as lightweight relatively stress free action and furniture modules.

From there, the barrel is mounted in one point only, at the barrel nut on the nose of the upper. With a free float handguard, it's instantly target grade construction, even if the barrel isn't. Add the precision caliber of choice, good ammo, and optic, you get rifles that look Service grade that can and do outshoot traditional receiver bolt guns. The match grade AR15's have run off all the M14's from the top shooter awards for years now.

Saying it can't happen isn't very realistic, when apples to apples are compared, loading one round at a time in a precision rifle, the AR is giving traditional bolt guns a serious run for their money. Now that it's in the second half of it's century of development, there's very little difference in accuracy, once the fundamental action is understood.

In a timed contest of who can put more rounds into a bullseye, the AR can and does achieve a higher score in a shorter period, precisely why we got rid of bolt guns on the battlefield. It's a very limited and restricted situation to say a bolt gun is better when in the larger scheme of what guns do, they are nearly the same as muzzleloaders.

 

[Tim the student]

An AR type rifle might rival the accuracy of some bolt rifles, but not a high quality bolt rifle.

I think that depends on how you define "high quality".

Or, did you mean "high precision"?

 

[d2wing]

Great videos and explaination Stephen. I also notice on the other rifles the gas tube affects barrel movement too.

 

[ball3006]

Any gun is only as accurate as the guy driving the trigger can shoot........don't sweat the small stuff. I have out shot many guys at the range who were shooting 1000+ rifles with my 90 dollar Mosin Nagant. They just can't believe a cheap rifle can out shoot theirs..........chris3

 

[waldonbuddy]

Well, now you all have got me interested in the AR15. What are some of the most accurate AR15 versions?

 

[wanderinwalker]

But can you win a national or world championship with a semi-auto? Sorry but not yet.

Define your game and national championship. The NRA National Highpower championship was won by G David Tubb in the 90s with a modified SR-25. Carl Bernosky won a title in the last few years with a modified AR-15 in a 6mm chambering IIRC. (This year was won by Sgt. Sherri Gallagher of the USAMU using a Tubb 2k in .260 Remington.)

Again, I agree at ultra-long ranges where the extra horsepower of larger cartridges becomes an asset, the bolt action will have an edge. And in benchrest the bolt action will rule. But at the ranges your average shooter is realistically capable of making hits at from the shoulder, the difference in accuracy is a wash.

 

[waldonbuddy]

Jeff56 said, "I don't plan on being on any battlefields anytime soon but even on battlefields there are still people using bolt action guns for long range accuracy. Sniper rifles have definitely made a comeback in Haji's backyard."

News break, the military is using AR 10's as sniper rifles...
http://www.military.com/forums/0,15240,146717,00.html

Quote from the link above:

"With the obvious merits of current self-loading sniper rifles, these weapons came to be seen as the potential equal to the bolt-action repeater in accuracy, not to mention their superiority in a target rich environment such as has been common in the G-WOT."

 

[suzukisam]

Look I have nothing against semi-autos. I intend to get one myself at some point. I have semi-auto centerfire rifles already but I want one that will shoot more accurate than the ones I have. But even the ones I have are fairly accurate to about 300 yards.

it sounds to me jeff like you have little experience to speak from? lets set a standard for what is accurate? 2 moa, 1moa, 1/2 moa, 1/4 moa? most factory bolt guns require a lot of work to achieve 1/4 moa? Any AR with a barrel swap has the potential to be a 1/4 moa gun. I would guess there are many reasons other than just accuracy that classic bench guns are bolts and not in the AR platform. They don't have a long magwell, pistol grip, and the stock is interchangeable. To convert an AR to bench you need a very heavy duty free float tube, and resting piece(don't know the name). because a bolt is more practical for a competition doesn't mean that they are not as accurate. like I said the barret 50bmg is basically a very large AR, and they have proven accurate out to distance in the miles not yrds. I love both too, but people who don't understand AR's or are old school when it comes to bolts should understand that whether or not you like them they are ridiculously accurate.

There are also many advantages to the AR that you cannot get from a bolt gun. with a break of some sorts, you can make instant follow up shots and never loose sight picture in a fairly heavy caliber, at long ranges. that is hard to do with a bolt gun. large mag capacity in a large caliber. most bolts don't hold ten rounds of 308 or 300wsm. ar's are completely modular. you can switch from 308/260/243/7mm-08/ in seconds if you have another upper. I have to ARs that shoot consistant 1/2 moa. I have gotten 1/4 moa out of one, but honestly my skills can't produce that repeatedly, so I can only say for a fact that I have a 1/2 moa or better gun(s).

 

[TonyAngel]

I've gotta say that I LOVE ARs. I think that they're the best thing since sliced bread, but I don't think that an AR could ever be as accurate as a bolt gun. I'm not talking in terms of practical accuracy. I am talking about splitting hairs.

I don't know why it is, but from what I've seen, it just is. I was bitten by the precision bug not too long ago and since I was into ARs, I built an AR. Actually, several of them. I was never able to attain the consistent 1/4 MOA accuracy that I was looking for. The shame of it was that I had spent an almost ungodly amount of money building a 1/2MOA AR. Then I decided to try a bolt gun. I got a Remington SPS Tactical. That's a $550 rifle. I threw my scope on top of it and shot my very first five shot .2" group with it, stock out of the box. I've shot quite a few groups in the .2s and under since then. I've never seen an AR do that.

I've also found that it's easier to get a bolt gun to shoot well. You have a lot more room to work with in terms of seating depth and powder charges. With ARs, there's just no getting around the fact that you have to work with the gas system. Too light and the gun won't run. Too heavy and you're beating it to death. Too long and you're single feeding. Too short and it won't feed right from the mag.

Of course, if you have no need for a 1/4 moa rifle, a AR could very well be enough and is enough for most. I'm sticking with bolts guns for precision type shooting personally because I'm anal and I do want a 1/4 moa rifle. Secondly, pound for pound, I think you get more rifle with a bolt gun.

 

[mes228]

Rifle

Don't know why but EVERY AR type rifle I've owned was accurate. I've had several by different makers. The Daniels Defense & FN I have now are both really, really accurate rifles. I like the AR platform a lot.

 

[Picher]

The AR, with free-floating match barrel is an amazingly accurate rifle, but a lot of the accuracy people achieve is due to the cartridge and lack of apparent recoil. People shoot rifles with less recoil much better than they can heavy-recoiling rifles, especially when shooting long strings.

I have an extremely accurate .223 Rem Tikka bolt-action that will shoot rings around most other bolt actions and ARs, but I shoot hand-loaded rounds that have been shot at least once in that chamber, minimally re-sized to fit very well and quality bullets. The action has been pillar-bedded into the stiff stock and barrel free-floated. Bullets are seated precisely and close to the rifling to maximize alignment. That rifle will shoot 1/4" groups with good bullets.

Conversely, I've shot out of the box bolt actions by pretty good manufacturers with 30-06 and larger cartridges that wouldn't group better than 2", regardless of ammo.

A few years ago, I bought some cheap .223 UMC FMJ ammo that wouldn't group better than 1 1/4" in my Tikka. One day, I was out of handloads and wanted some ammo to shoot varmints that morning, so I pulled the bullets out of the UMC ammo and replaced them with Sierra 55 grain spitzers, but didn't do anything to the powder charges. That simple change made the rounds shoot 5/8" at 100 yards, or at least half of what the factory bullets could do!

 

[suzukisam]

Jeff- I wasn't "jumping all over you" I wasn't even trying to offend you. you said you never had an accurate semi. It was a fair assumption to say you had no experience with them. and I was not being smart, I was asking what is the standard for accuracy. The 1/4 MOA comment was an example. you have to understand that when a company designs semi auto battle rifle accuracy is not usually the first priority. So to say one may not be accurate is fine, but to say they cannot be as accurate, I think is incorrect. I think people read the tone in anothers response as they assume it is. I'm not being snarky. and your not being ganged up on, I'm just addressing your statements. when I said a Barret is like a large AR I was making a comparison to semi autos in general, as semis go those two are fairly similar. I'm sorry none of the heavy barreled ar you shot were accurate. and I never set the standard at 1/4 I said I have gotten those groups, but mine are both 1/2 all day long. and a 1/2 is not that big of a deal from a good krieger, shilen, WOA, and others. a good trigger and a krieger and about any AR is shooting 1/2 moa. free floated of coarse

 

[Art Eatman]

Rigidity of the system seems to be a major factor in bench rest competition, right? Seems to me that the more moving parts you have, the more expensive it is to get the precision and close-enough tolerances to have rigidity when the bolt is locked in.

Sub-MOA isn't all that difficult. Reliable half-MOA is a challenge; even moreso to get down to 1/4. Lotsa bolt guns don't get down to 1/4 MOA.

I dunno. I figure that a fella oughta figure out what he needs or wants, and then takes a long look at his billfold.

 

[suzukisam]

@jeff

Dude you are so wrong... but anyway

Op- for your average guns off the shelf 1moa is considered standard by many companies. About any AR you pick up off the shelf will give you that accuracy. There aren't many current production rifles that won't. Although some of my weatherbys have had poor accuracy right out of the box. Of all the rifles I've pillar bedded and floated the barrels it seems to me that with "bolt on parts" I could get as good accuracy from my ARs I would say it is a very fair statement that out of the box they rival bolt guns

 

[george357]

Average off the shelf AR's ARE as accurate as average off the shelf bolt rifle's. Compare any "economy" version of each and they will be close to equal. Compare "expensive" versions of each and you will see an increase in the accuracy of each type. Work on either one and you will get better than average accuracy from each. It's pretty simple. Some can accept this truth, some can't.

 

[waldonbuddy]

What the OP, me, was trying to figure out was the why the AR design of rifle's would rival a bolt action rifle in accuracy.

I didn't give perimeters to what barrel vs bedded or unbedded, etc. I think all of you here have heard about the out-of-box accuracy of the AR design, I just was curious as to the why of it.

I think there are some very intelligent people here who have explained this so well that I should be posted permanently somewhere, here or in print.

The accuracy of the bolt action rifle is {at least to me} easy to understand. Everything on a bolt action rifle, bar for short, is made rigid, and its all centered, and nothing moves vs a semi.

The accuracy of the AR with its moving pieces confounded me how its a very accurate rifle right out of the box. I have a MSAR with a 24 inch heavy barrel, an Armalite AR10 with an 18 barrel, a custom built 7.62x39 Galil, a Remington Police special bolt rifle, and an M1A1.

None of my rifles shoot as accurate as my AR10, maybe thats just the rifle for me, but after reading all of the replies here I don't believe it for a moment. Its the design of the rifle pure and simple.

However, I don't know, and won't argue that the AR is better, or the bolt rifles are better accuracy wise. I would choose the AR design for the versatility of it, as well as quicker follow up shots. I know that is not what this topic is about, I just wanted to say that is where I stand as far a preference.

Thanks to all for explaining this to me.

 

[wanderinwalker]

And since I don't know the setup for those championships mentioned I can't really comment on them. Are they multiple shot contests where speed counts? That isn't just about accuracy is it? The point of the discussion is accuracy. And again the OP didn't mention anything about the average shooter and what he's capable of doing. And if he did that isn't really something that is new. Again the M1 was a very accurate rifle at long ranges. Yes semi-auto's have become more accurate since WWII but I've seen people shoot those M1's and be incredibly accurate with them to 600 yards or more. I'm talking minute of ground hog.

NRA Highpower competition is usually conducted as an 800-aggregate (80-round) course of fire requiring 20-rounds in 20 minutes of offhand at 200 yards, 2 10-round strings of "rapid" fire from sitting at 200 yards, 2 10-round strings of "rapid" fire from 300 yards prone, and 20 rounds in 20 minutes at 600 yards prone. There are other courses of fire (500-point aggs modeled after the National Match course and 1000-point aggs requiring 40 rounds from 600 yards are the most common ones I've run into) and reduced courses and targets for ranges that have limited space.

I quote "rapid" fire because the time limit is 60-seconds from 200 yards and 70-seconds from 300 yards (10-shots, with a reload). It's quite generous and custom bolt actions probably still rule the Match-rifle class, though AR-based guns are very popular as well. (I shoot Service Rifle, so we're limited to M-1 Garands, M1As and AR-15s, with the black rifles being the dominate rifles.) There is an optical sights class that is a recent addition, but I think I've only ever seen 1 or 2 shooters shooting across-the-course with a scope.

 

[d2wing]

This thread has been very educational for me. I wish I could afford that K.A. M110 sniper rifle. I wonder what the military pays for them?

 

[Tim the student]

My out of the box RRA Varmint EOP outshoots my out of the box Savage 111 (non accutrigger) - by a good margin. The Savage is about always right around 1MOA, BTW. For whatever thats worth - with my huge sample size of 1.

We shall see if the RRA outshoots my new Savage 10.

 

[mljdeckard]

The M110 as used by the 19th SF group with the suppressed barrel is $14k. And it sucks. They say if they shoot it faster than 6 rounds per minute, it starts to heat up and jam. The old E-8 I was shooting it with says he prefers to just pull an old M-14 out of the rack.

HOWEVER, I can see a lot of this being reluctance to change and accept a new idea. I will tell you I did better with the first three shots on that rifle than I did with the first 50 through my Remington 700 PSS. I'm building an AR-10 now.

 

[benzy2]

I feel a big part of why $1000 ARs shoot well compared to many $1000 bolt rifles has to do with stocks and bedding. A float tube and a fixed stock are very rigid and don't interfere with the barrel. A wood stock on a bolt rifle can have all sorts of issues impact accuracy. While a bedded quality stock may work very well, there are few that are quality stocks, let alone bedded well, in the sub $1000 range. Add in a decent barrel blank finished fairly well to a float tube and fixed A2 stock and you get yourself a shooter.

Now, take all the guys who are used to shooting common bolt rifles that hold 1/2moa at best and 2 moa at worst, and this AR that shoots 1/2 to 3/4 moa out of the box seems like the best thing since sliced bread.

When you get to top tier bench rifles, bolt actions dominate. But, for the bulk of us, it is irrelevant as those rifles are extremely purpose built and aren't something the masses use. So we really need to define if we are talking in absolute terms of accuracy, or common man for the dollar terms.

 

[snake284]

I have an old Model 70 post screw up (1966) model that shoots very well. I always wished it were a Pre 64, until I figured out it would outshoot most pre-64s. One reason is that I pillar bedded it with the old Brownells Accubed back in the early 80s and reworked the trigger. It breaks clean at about 2 pounds. Back in the day and until about 5 years ago, it would shoot Sub MOA, about 3/4 inch. I am not sure if it was just coppered up or it is burning out. But I bought it in 1966 brand new and have shot it quite a bit. So it could be the barrel going south or it could be just copper. I cleaned it with Deaton's Deep Clean night before last and want to try it out this week to see if it helped. It had lots of copper and I finally got it where a white patch came out pretty clean. Deaton's is the best copper solvent I've seen bar none. It takes very little effort to get all the copper out of your bore with it. Do a search on Deaton's Gun Care Products on the Net. Also what was that other one that was pretty good. Dang I can't remember. I'll think of it later and post it. Copper is not your friend.

 

[waldonbuddy]

What are the most accurate AR rifles out there? I would like to buy one in the future.

 

[suzukisam]

waldon- what makes an AR accurate is the barrel... thats it. the trigger helps you shoot better but the gun only needs a good barrel. one of my good friends builds 1/2 and 1/4 moa ARs. you could take about any cheap AR throw a krieger, WOA, Shilen, ect and you'll have tack driver. people get just as dumb about ARs as they do 1911s or glocks or anything else. my pro has a 6.8 built on blem receivers and he is getting 1/4 moa @100 yrds. but it has an 18" WOA with a linear comp and a vtac rail, and an armalite trigger... it's all about the barrel baby!