semi-auto and bolt rifle's accuracy?
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USMCRotrHed
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It's mostly about repeatability of the firing cycle. A bolt rifle has less moving parts and therefore it is easier to repeat the exact same firing sequence each time.
A semi-auto goes through several different motions each time it is fired and each moving part may or may not repeat exactly the same every time.
A semi-auto goes through several different motions each time it is fired and each moving part may or may not repeat exactly the same every time.
EvisceratorSrB
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There is not an inherent quality of actions. ALL bolt actions are NOT more accurate than ALL self loaders. Most of the accuracy depends on many more factors than action style such as quality of pieces it's made of quality of assembly etc. In general, bolt actions are generally more reliable and manufacturing is detailed and good. With other bolt actions this is not the case. It just matters on manufacturing capabilities.
30Cal
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A bolt action generally doesn't have a bunch of junk hung off the barrel. Many semi-auto's even have moving parts on the barrel itself.
rra_casper
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I've been told that it's because the only part of a bolt gun that moves when the trigger is pulled, is the firing pin. This makes the gun more stable in your hands than a semi-auto, where large pieces of the action may or may not be moving around before the bullet has even left the barrel. Correct me if I'm wrong.
30Cal
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They may not be cycling, but that doesn't mean that all those parts are perfectly fixed. If you shake it, it'll rattle.
Oregongundude
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I don' think it matter how many moving parts are in the rifle.
I had a bolt action springfield 30.06 for years and it's couldn't hold a candle to Browning Gas operated semi-automatic .308 in accuracy. It's all in the sighting and the shooter trust me on that.
I had a bolt action springfield 30.06 for years and it's couldn't hold a candle to Browning Gas operated semi-automatic .308 in accuracy. It's all in the sighting and the shooter trust me on that.
rangerruck
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also every time a new round is stripped from the mag, small even microscopic grooves, are cut and chattered into the next round down in the mag, from the bolt head and round taken from above, then it goes into the chamber, which if it doens't go in right down the middle, can get little imperfections again, this time on the bullet itself. they may be tiny, but these little imperfections, will cause differing aerodynamics on each successive bullet.
R.W.Dale
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It largely boils down to the fact that your average bolt action rifle is a more rigid bullet launching platform that has fewer parts to hold to closer tolerances than your avg semiauto.
R.W.Dale
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That is just one example that proves nothing.
Heck I have a scoped sks that shoots like crap but my CZ527 in the same caliber shoots great...Yet you don't hear me saying every bolt gun is more accurate than every semi.
jackslayer
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It seems to me that bolt action rifles are GENERALLY more accurate because they are GENERALLY built for applications that demand acuracy. Hunting and target shooting. IMHO it seems the barrels that go with these rifles would have a special level of attention to the barrel. its a what came first argument. Not all bolts are more accurate. Most will agree. Some have made the claim that a bushmaster varminter is the most accurate .223 available. (for a full article go to gunblast.com). It seems that semi-autos are made for rapid fire and plinking in GENERAL. my .02.
Medusa
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Vibrations. The less things the barrel is attached to, the lesser they are and thus the gun is more consistent and this leads to accuracy. That's why the good bolt-actions have bedded barrels and mostly the only thing the barrel touches is the receiver it's attached to. Also, when shooting the barrel warms and most metals expand when heated, if the barrel is free floating then it doesn't bend the barrel, thus doesn't move the point of impact. If the barrel is attached from 2 places and the lenght of barrel between these 2 mounts increases a little, the barrel suffices a slight bend, AFAIK.
Sure, there are several very precise semi-autos, where everything that is attached to barrel is fixed so that the vibrations are at least consistent ones, like 1/2 moa guns PSG1, Mk11 mod0, or 3/4 moa guns, like MSG90 and M21. But semi-autos (especially the mentioned ones) tend to be more expensive than bolt actions of same accuracy.
As said before, it's a thing of manufacturing standards and quality control.
Sure, there are several very precise semi-autos, where everything that is attached to barrel is fixed so that the vibrations are at least consistent ones, like 1/2 moa guns PSG1, Mk11 mod0, or 3/4 moa guns, like MSG90 and M21. But semi-autos (especially the mentioned ones) tend to be more expensive than bolt actions of same accuracy.
As said before, it's a thing of manufacturing standards and quality control.
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wanderinwalker
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Barrel harmonics and vibrations. The bolt-action, as noted, can be made with the barrel completely free-floating and therefore not interfered with. Most semi-autos are going to have holes in the barrels for gas ports, gas tubes, towers, op-rods, pistons, etc, all dangling around.
But this is not a hard-and-fast rule. My experience is that a good, solidly built match-grade AR-15 will easily hang with a bolt-action for practical accuracy. At 100 yards off of a benchrest there will probably be an edge to the bolt gun. At 300 yards, rapid fire with a little breeze, it becomes a wash.
Edited: AR-15 are generally considered easy-to-fine-tune because they don't have much hanging off of the barrel. Add a free-float tube and a good barrel and your accuracy work is most done.
But this is not a hard-and-fast rule. My experience is that a good, solidly built match-grade AR-15 will easily hang with a bolt-action for practical accuracy. At 100 yards off of a benchrest there will probably be an edge to the bolt gun. At 300 yards, rapid fire with a little breeze, it becomes a wash.
Edited: AR-15 are generally considered easy-to-fine-tune because they don't have much hanging off of the barrel. Add a free-float tube and a good barrel and your accuracy work is most done.
MachIVshooter
Member
Bingo.
One more factor that has also been pointed out is what happens to the bullet itself during chambering. Manual bolt actions are not nearly as violent in feeding, which means less bullet deformation. A closer-to-perfect bullet means better accuracy. This is why single shot bolt guns tend to be even better-no feed ramp to marr the bullet or distort the case.
R.W.Dale
Member
NO
1. Hammers tend to wreak havoc on extreme accuracy through the extended lock time they create.
2. that whole BREAK action part tends to be a few steps behind semiauto rifles in terms of rigidity and stiffness and lightyears behind a quality bolt gun.
Look at a bolt action rifle out of it's stock. they are little more than a tube with a few holes in it here and there. You wouuld be hard pressed to improve apoun that in terms of stiffness and rigidity
The most accurate rifles are singls shot bolt actions where the only cut out is the loading gate (no mag)
Also, many semi-auto guns out there are designed for reliability first and accuracy second. An AK is probably the first that comes to mind on this. They are also designed to function even when dirty so that often means looser toleraces in some places that may rule out fine accuracy. Most really accurate semi-auto guns are also somewhat expensive.
Of course, accuracy is relative to what the shooter expects.
In general, I wouldn't use military surplus rifles as a base line for real accurate bolts gun. Surplus guns come in all conditions and one may not be as accurate as another. Some are accurate, but some may not be. Depends on the design and the condition of the particular rifle. You could probably say the same thing about any used rifle to be honest, but surplus guns are a bit older than most.
Of course, accuracy is relative to what the shooter expects.
In general, I wouldn't use military surplus rifles as a base line for real accurate bolts gun. Surplus guns come in all conditions and one may not be as accurate as another. Some are accurate, but some may not be. Depends on the design and the condition of the particular rifle. You could probably say the same thing about any used rifle to be honest, but surplus guns are a bit older than most.
.38 Special
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Lots of good replies. Seems like the bases have been covered. I will add, though, that there are some seriously accurate semi-autos floating around out there. Several companies are specializing in accurate AR-15s. I had one from Eagle Arms that was a genuine 1/4" rifle for five shot groups.
rangerruck
Member
Nope. because the curved areas of the bullets especially the tip, and near it, don't engage the rifleing.any little deviation up there is going to effect the trajectory. Imagine if you will , throwing a baseball and a little flap of the cover is not threaded down. Or throwing a football, and the front of the ball, towards the nose , has some of the lacing coming loose. Every bit of this, no matter how small, will change it's trajectory.
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