Autos or Bolt Action More Accurate?


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Drakejake
March 11, 2005, 08:21 AM
I am having an argument with a friend. I stated that bolt action rifles are generally more accurate than auto or semi-auto rifles and that bolt action is the primary choice for American competitive shooters and military snipers. I know that there are some high end AR's, etc., that are billed as match rilfes. I kow that there are some competitive, rapid fire shootoffs which involve autos. But isn't it generally true that when accuracy is the main goal the bolt action rifle is the most common choice? My friend is suggesting that autos are just as accurate as bolt actions and are currently being used by U.S. military snipers.

Thanks,

Drakejake

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MrMurphy
March 11, 2005, 08:29 AM
For extreme accuracy the bolt will always win. There's no parts moving except the firing pin.

Some autos can be made as accurate, for example some of the AR's, the semi-auto .50s, etc. However it's easier to make an off the rack bolt gun more accurate (freefloat the barrel, true the chamber, etc) than an off the rack AR-15.

For some roles, such as designated squad marksman, sniper support (observer's rifle) etc they want a highly accurate semi because they want good accuracy with a scope out to say 500 yards, but they also want rapid fire on demand in the case of multiple targets at close range, so there is indeed a market for very accurate semiauto rifles.

But for really long range shooting, normally the bolt gun wins. He's so far away the split second extra to work the bolt is irrelevant since the idea is to do it with one shot anyways.

I'd say 90% of the sniping rifles used for true long range work (800-1,000+ yards) are bolt guns, the M107 (Model 82 .50 BMG Barrett) being the exception.

The British Army and Royal Marines, our Army and USMC and Air Force snipers all use bolt guns. Most European snipers use bolt guns. The Russians use the Dragunov for closer range and I hear they have a really tricked out Mosin-Nagant type for the really long range accurate stuff, though I may be wrong. The Canadian Army uses bolts (the longest shot in sniping history, 2,500+ yards in Afghanistan, was made by a Parker Hale .50 cal bolt gun with Canadians on the trigger and the scopes observing).

The majority of police snipers use bolt guns too. Some will have a really accurized AR (I know a police lieutenant with a 20" heavy barreled scoped DPMS in his patrol car) but for a 100-200 yard shots it's a lot easier to make an AR accurate than say for a 800-1,000 yard shot (though AR's that can hit at that range exist, they use them at Camp Perry).

cracked butt
March 11, 2005, 09:17 AM
Think of a semiauto like an AR-15, M1, M14, Browning BAR (sporting rifle), remington 7400 as nothing more than a gas operated bolt action. They all have rotating bolts that lock up like a bolt action. A remington 700 is a simple bolt action with very little mechanical complexity. It can be made to tight tolerances and still fuction properly. With a semiauto, tolerances need to be a bit looser, and everything has to be timed correctly for it to function reliably.

One could conceivably take an M1 or and M14 and prep it to shoot as good as a factory made remington 700 in the same chambering, but it would cost 4x as much as the bolt action.

Art Eatman
March 11, 2005, 11:57 AM
For a given amount of money, time and effort, a bolt-action is more accurate than a semi-auto.

A production-run bolt-action rifle is rarely less accurate than a semi-auto. Generally, it takes a "match target" or equivalent semi-auto to equal or exceed the accuracy of a run-of-the-mill bolt-action.

Art

DMK
March 11, 2005, 04:48 PM
As Mr. Murphy said, Police marksmen almost exclusively use bolt actions(as do most military markmen for that matter). That should say something in itself, especially when you consider that more and more of the rest of the police are including semi and full autos in their kit.

LeonCarr
March 11, 2005, 06:33 PM
I believe that Canadian sniper in Afghanistan used a bolt action McMillan .50, not a Parker-Hale. Is Parker-Hale still in business?

Just my .02,
LeonCarr

g56
March 11, 2005, 06:44 PM
The shooters in the service rifle matches at Camp Perry have their choice between the 03 Springfield, M1 Garand or the AR15, the 03 Springfield is by far the least expensive match rifle, but the winners at Camp Perry are almost always shooting AR15's. The cartridge resides in a chamber behind a rotating bolt in all 3 of those rifles, how does it tell the difference?

Jim K
March 11, 2005, 08:13 PM
The cartridge doesn't know the difference. What is different is what happens once the round is fired. As the bullet moves down the barrel, the less that happens to the rifle in the way of disturbing things, the better.

If all that happens is normal barrel vibration (unavoidable), proper bedding likely can counter it. But every thing you hang on the barrel by way of gas cylinders, pistons, and the like will affect the barrel in a different way, making compensation very much more difficult. And then, at some point other parts of the rifle become active moving parts, not just static parts. Pistons move, operating rods start flying, and all while that bullet is still in the barrel. Each movement creates its own vibration and affects, in the final analysis, the position of the barrel when the bullet exits.

All this can be dealt with and controlled, but it requires more analysis, more time, more work to do so than with a simple bolt action. Add in the weight factor, and things get worse. One criteria of the modern military rifle is that it be lighter in weight than the old guns. It is not that today's young soldier is weaker than his father or grandfather, it is that he is expected to carry more weight in other stuff, mainly ammunition.

So military rifles today tend to be light, with light barrels. That means more vibrations, and more work to control them and produce accuracy.

Jim

4v50 Gary
March 11, 2005, 09:16 PM
What Mr. Murphy & Jim Keenan says. You can take two equally good barrels and and put one on a semi and make the other a bolt. Feed them the same ammo. Have the same shooter shoot both. Then it'll boil down to the winner being the bolt gun. It's a matter of less things to interfer with the barrel harmonics.

cracked butt
March 11, 2005, 09:47 PM
The shooters in the service rifle matches at Camp Perry have their choice between the 03 Springfield, M1 Garand or the AR15, the 03 Springfield is by far the least expensive match rifle, but the winners at Camp Perry are almost always shooting AR15's

You are forgetting the fact that the mouse caliber has a lot less recoil than the '06, the AR-15 has much better sights than the '03, and the ergonomics are substantially better on the AR-15 than the old '03. I would take a standard issue AR-15 that shot 2 moa over an accurized '03 that shot 1 moa every time for high power competition.

MrMurphy
March 11, 2005, 10:33 PM
The M1905 rear sight on the 1903 Springfield is an excellent target sight. Crappy for combat, excellent for long range shooting.

Lobotomy Boy
March 11, 2005, 11:28 PM
Because the receiver on a bolt action has less metal machined away to make room for hardware, it is more rigid than the receiver on a semi-auto. I suspect that this contributes to the greater accuracy of the bolt.

cracked butt
March 11, 2005, 11:31 PM
The M1905 rear sight on the 1903 Springfield is an excellent target sight. Crappy for combat, excellent for long range shooting.

It'll work if you get the proper dope on the sight. Without any kind of click adjustment, there is no way you can change your elevation settings on the sight and be dead on unless you had an O'hare micrometer to set the sights with. The 03A3 rear sight is a better battle sight but lacks the adjustability of the 1905 sight. At any rate, the rear sights of US service rifles starting with the M1 are still a vast improvement on the 1903's sights.

YodaVader
March 12, 2005, 12:44 AM
The shooters who are probably the most obsessed with accuracy are those in sanctioned benchrest competition. All the true competition benchrest rifles I have seen have been bolt actions.

wanderinwalker
March 12, 2005, 09:29 PM
The shooters in the service rifle matches at Camp Perry have their choice between the 03 Springfield, M1 Garand or the AR15, the 03 Springfield is by far the least expensive match rifle, but the winners at Camp Perry are almost always shooting AR15's. The cartridge resides in a chamber behind a rotating bolt in all 3 of those rifles, how does it tell the difference?

g56, you forgot the M-14/M1A. ;)

The M-1 and M-14 systems use op-rods and bolts, everything which hangs off of the barrel or just about so. Plenty of things to set up funky vibrations and throw off bullets. A tightly bedded and tuned M-1/M-14 is accepted as being capable of reliably showing 1-MOA 10-round groups. An AR-15 with less trickery and $$ is capable of around .75-MOA for a really good one. (And 3 or 5 shot groups don't matter in Highpower, because we're printing 10 or 20 in a row.)

The AR-15 "Mouse Gun" can hang with the .30s at 600 yards and walk away from the big guns in the rapid fires. No question, seen it plenty. And Highpower rests on being able to shoot from 200 to 600 yards. My AR and I have been outshot at 600 yards by bolt-action shooters who weren't quick enough or accurate enough at 2 and 3 rapid to make a difference. That is why the top shooters in Service Rifle primarily use the AR-15.

In the end, the bolt will be more accurate; just look at bench-rest shooters. But when using the rifle in a dynamic, shooter-supported position type event, the way the rifle fits and jives with the user matter more than the pure accuracy potential. In which case either type seems to work as well.

bogie
March 12, 2005, 10:48 PM
The function of the action is to hold a cartridge in a barrel, and hold the barrel and the cartridge in a consistent fashion.

The bolt action does this better...

Remember a few years ago when Feamster shot a benchrest match with one of his space guns?

My gunsmith was there. He said Feamster shot an incredible group. Only problem was that it was on only one of something like 10 targets shot for the day. Overall, mediocre.

Consistency is what matters. If you're carrying around a group in your wallet, throw it away. It don't mean squat. If you can carry around five groups like that, all shot the same day, they'll _maybe_ match up to what a mid-tier benchrester can do. With a practice barrel. In the wind.

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