Bolt action vs. Semi Auto

[Diana's Angels]

I was wondering why are Bolt Action Sniper Rifles prefered over Semi-Auto? Every time i see a sniper rifle it is almost always Bolt Action. Why is this?

 

[30Cal]

In theory, they're inherently more accurate (no stuff hanging off the barrel). It takes very little work to get a bolt action to shoot under a minute. It takes a lot more work to make that happen in a semi-auto. Also, semi-auto's (at least in the configurations the military has) don't take well to being saddled with a scope and then the scope ends up being too high up for good precision shooting.

Ty

 

[ocabj]

The key advantage is consistency of chambering the live cartridge into the bolt action. The bolt action involves the operator to hand operate the bolt, pushing the bolt forward, thus pushing the cartridge into the chamber, and rotating the bolt lever/head to lock the bolt into place for firing.

A semi-automatic on the other hand relies on the operator to manually feed the first round. Then all subsequent rounds are chambered by the rifle itself during the gas or blowback operation of the action. How consistent the chambering of each round by the action comes into play.

Also, since the bolt action rifle is operated manually for feeding each and every round, tolerances for the bolt will be a lot tighter, thus increasing consistency in the action. Whereas semi-autos will need some 'looseness' in the tolerance in order to achieve reliability (ie: AK-47 family has very loose tolerances for maximized reliability, M16 family has tighter tolerances for more accuracy).

Not to say you can't have a semi-auto rifle with great accuracy. The H&K PSG1 supposedly has sub-MOA accuracy if you read all the literature on it (and play enough Rainbow 6 video games...).

 

[BozemanMT]

as they said
more inherant accuracy
Besides, it's a sniper, one shot, one hit, I think that's part of it too, instill that sense of one shot, one hit.

 

[WiLLtallica]

A lot of the more accurate paintball markers do fire with the same principle in mind. Round is prechambered, and the bolt does not move during each shot, but before it's dead (closed bolt operation). Supposedly the bolt being still is what plays into a straighter, and further shot. Still under certain conditions there is absolutely no difference in accuracy between the types, and the more expensive open bolt markers do shoot just as straight as closed bolt markers.

 

[JohnBT]

Autoloaders typically have slightly larger chamber dimensions than bolt actions to ease feeding. With a larger chamber the cartridge ends up pointing a little bit this way one time and a little bit that way the next. It's not good for accuracy.

www.riflebarrels.com/articles/barrel_making/rifle_barrel_accurate.htm

"One of the most important pieces to the puzzle is a straight and uniform throat that is concentric to the bore. The bullet must get started into the rifling straight. If it doesn't; it will become somewhat deformed and will not be centered in the barrel. Upon exiting the muzzle it becomes free to rotate around its new center-of-gravity, departing from the centerline of the barrel. In effect it will make a corkscrew-type path around the barrel centerline."

 

[Texas Gunman]

I agree about bolt action being accurate etc etc, buttheir is alot of auto rifle able of exstreamly tight groups.
My AR, I can place five rounds in a nickle size circle at a 100 yards easily.

I have a mauser, love the action on mausers.

TG

 

[rangerruck]

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.

 

[slzy]

there have been several semi military snipers,compared to police snipers. as maj. plaster opines in his book,the police sniper MUST hit his target,whereas the military sniper even if he misses slows the enemy down,instills fear,lowers morale etc. other advantages for the semi military is rapid fire if being assaulted,and more stealth than working a bolt. examples would be,among others the m1d,m21,svt40 svd,psg1 and others from hk m78 from finland,etc. and ma deuces have scope mounts.

 

[crunker]

I prefer lever-action sniper rifles over bolt, as you don't have to take your hand off the gun in order to chamber a round.
Semi-auto is good for target shooters and police, but for military use it takes a little too long to prep for usage.

 

[Prince Yamato]

I thought the whole reason for bolt-action vs. semi-auto is that the semi-auto will send the brass flying, whereas with a bolt-action, you can easily catch each bullet yourself.

 

[ocabj]

Semi-auto is good for target shooters and police, but for military use it takes a little too long to prep for usage.

Actually, that is counterintuitive to the trend in today's infantry squads. The M14 and DMR versions of the M16 are now being used by infantry designated marksman, otherwise known as SDM.

 

[slzy]

crunker,could you give us a checklist on snipers "prep" and an update on lever action sniper rifles?

 

[IdiotFool]

I know this topic is old, and I apologize for the bump, but I wanted to know - does having a magazine/clip also decrease, theoretically, the accuracy? In other words, which is more accurate - single shot or automatic? What if you use the magazined rifle as a single shot and hand place each bullet? Does having the magazine there effect the weapon?

Thanks!

 

[cat_IT_guy]

As I understand it, the addition of a magazine well actually can reduce the accuracy b/c it makes the stock and reciever less stiff, however minute this difference may be.