What makes bolt action the most accurate?
08-27-2005, 12:55 PM
#1
Thread Starter
Join Date: Feb 2003
Location: Helena MT USA
Posts: 363
What makes bolt action the most accurate?
This stems from a post by Vapodog concerning bolt action accuracy. I realize this must be a rookie question but why is a bolt action considered more accurate than other rifles?
08-27-2005, 01:15 PM
#2
Dominant Buck
Join Date: Feb 2005
Location: WC FL
Posts: 26,323
RE: What makes bolt action the most accurate?
An accurate rifle will have a blueprinted (trued) action, properly fit barrel with a concentric crown, trigger job, good bedding, and quality ammunition made to match the chamber.
08-27-2005, 01:16 PM
#3
Nontypical Buck
Join Date: Feb 2003
Location: Western Nebraska
Posts: 3,393
RE: What makes bolt action the most accurate?
historically the other guns was M-94 winchesters and the like....they was not ever a match for the bolt action and are not today.
I've seen Remington pums do very nice groups.....and I suspect Browning's BLR will show the targets some good performance and again I've also seen the BAR shoot very well. H&R handi rifles also have fared well as a "shooter"...
Ya know what?????....I just don't know.....but we never see anything but bolt action rifles at shooting matches do we?
Maybe someone can tell us why...this much I can say...I've never found a trigger on a pump or lever or auto as fine as some of the bolts I've used.
I've seen Remington pums do very nice groups.....and I suspect Browning's BLR will show the targets some good performance and again I've also seen the BAR shoot very well. H&R handi rifles also have fared well as a "shooter"...
Ya know what?????....I just don't know.....but we never see anything but bolt action rifles at shooting matches do we?
Maybe someone can tell us why...this much I can say...I've never found a trigger on a pump or lever or auto as fine as some of the bolts I've used.
08-27-2005, 01:33 PM
#4
Guest
Posts: n/a
RE: What makes bolt action the most accurate?
MT, its about repeatability. A bolt usually sets the charge off more consistently than say a lever, or a semi. Even if a semi or lever has the recoil lugs like a bolt,a boltseems it puts and holds it in a chamber more consistenty time after time. Also bolts can be easily modified to have consistent forearm pressure where a lever or most semi's can't.
But there is much more that makes up accuracy than just having a bolt.
But there is much more that makes up accuracy than just having a bolt.
08-27-2005, 01:40 PM
#5
Dominant Buck
Join Date: Feb 2005
Location: WC FL
Posts: 26,323
RE: What makes bolt action the most accurate?
What Makes For Peak Rifle Accuracy?
By Mike Bryant
What makes one rifle accurate and another inaccurate?? That is a question that many people have asked over the years.? The basic principles of rifle accuracy are the same whether you are dealing with a high-grade benchrest rifle or a bolt-action hunting rifle.
Most of my experience with rifle accuracy has been in competition benchrest shooting.? I shot my first match in the summer of 1982 and have been shooting in registered competition ever since.? My experience with rifle building began a little before I began shooting benchrest.? But in general, I have been stocking and later barreling the benchrest rifles that I shoot in competition since I started shooting competitively.? There is nothing like building tight necked 6 PPC's and Waldogs to teach you what it takes to make a rifle accurate.
There are no deep dark secrets to obtain peak rifle accuracy, only top quality mechanics.? For the purpose of this discussion, the rifle will consist of three major parts, the barreled action, the stock and the scope.? You cannot have top accuracy without all three parts pulling their weight.
The Barreled Action
The relationship of the barrel and action can best be thought of as how every part of the barreled action relates to the centerline.? The centerline is an imaginary line passing from the center of the bore through the center of the action.? The centerline may be imaginary but can readily be determined with the aid of a good 0.0001" dial indicator.? Of primary importance, the chamber has to be absolutely concentric and parallel to the centerline of the bore with the bolt face being an absolute 90-degree perpendicular to the centerline. ?The kicker here is that this is hard to accomplish because it is dependent on three different separate parts, the bolt, receiver and barrel and how they fit up to each other.
The bolt body, firing pin, barrel threads and chamber should be completely in line with the centerline of the bore.? The action lug recess, bolt lugs, bolt face, receiver face and barrel shoulder need to be 90 degrees to the centerline.? The bolt lugs and action lugs should make full contact on all locking surfaces.? The action threads and barrel threads should make full contact on the bearing surface of the threads with no contact between the top of the barrel thread and the bottom of the action threads. The chamber should be a size to precisely fit the cartridge case.
The shape or angle of the crown makes practically no difference as long as there are no burrs or irregularities in the crown and that one side of the bullet doesn't clear the barrel before the opposite side of the bullet does.? In other words, the barrel doesn't need to be longer on one side than on the other.
Why, you may ask does all this concentricity and 90 degree stuff make any difference?? The sole purpose is to launch a bullet precisely centered in the bore straight down the center of the bore and out the crown with as little wobble as possible.? If the bolt face is at 90 degrees to the chamber and the barrel bore, some of the relationships in the receiver don't have to be perfect and still you will obtain peak accuracy.? The thing is that it is far easier to obtain a bolt face perfectly at 90 degrees to the chambered barrel if every other part is in its proper relationship within the receiver.
An oversize chamber can ruin all your best efforts at building a tack-driving rifle.? The oversize chamber will allow the cartridge to lie in the bottom of the chamber and throw the bullet out of alignment with the bore.? Why then do benchrest shooters get such good groups when they are fire-forming brass?? The necks of their cases are turned to such close tolerances that the bullet is still in alignment with the bore as well as the case head is still supported by the chamber.
I haven't mentioned anything about barrel quality.? I have used barrels from most of the top makers of benchrest barrels and have had high quality barrels from all of the makers that I have used.? If you are going to economize on building a custom rifle, the barrel is not the place to do it.? Stick with a top maker and it's hard to go wrong.
Good triggers are critical for the accurate rifle.? Not that it is necessary for peak accuracy, but that it makes peak accuracy easier to obtain.? Two-ounce trigger have their place in the accurate rifle.? That place is on target rifles.?? With practice a two-ounce trigger can be squeezed and released if wind conditions change, but only if they are being shot from the bench.? Two-ounce triggers and field conditions don't mix.? I once had a two-ounce trigger mounted on my .280 deer rifle.? I was watching a coyote come into a windmill at 300 yards.? I placed my crosshairs on him and had a dead coyote.? Only thing was, I wasn't ready to shoot yet or at least, so I thought.? I replaced that trigger that day with a two-pound trigger and haven't used a two-ounce trigger on a hunting rifle again.
By Mike Bryant
What makes one rifle accurate and another inaccurate?? That is a question that many people have asked over the years.? The basic principles of rifle accuracy are the same whether you are dealing with a high-grade benchrest rifle or a bolt-action hunting rifle.
Most of my experience with rifle accuracy has been in competition benchrest shooting.? I shot my first match in the summer of 1982 and have been shooting in registered competition ever since.? My experience with rifle building began a little before I began shooting benchrest.? But in general, I have been stocking and later barreling the benchrest rifles that I shoot in competition since I started shooting competitively.? There is nothing like building tight necked 6 PPC's and Waldogs to teach you what it takes to make a rifle accurate.
There are no deep dark secrets to obtain peak rifle accuracy, only top quality mechanics.? For the purpose of this discussion, the rifle will consist of three major parts, the barreled action, the stock and the scope.? You cannot have top accuracy without all three parts pulling their weight.
The Barreled Action
The relationship of the barrel and action can best be thought of as how every part of the barreled action relates to the centerline.? The centerline is an imaginary line passing from the center of the bore through the center of the action.? The centerline may be imaginary but can readily be determined with the aid of a good 0.0001" dial indicator.? Of primary importance, the chamber has to be absolutely concentric and parallel to the centerline of the bore with the bolt face being an absolute 90-degree perpendicular to the centerline. ?The kicker here is that this is hard to accomplish because it is dependent on three different separate parts, the bolt, receiver and barrel and how they fit up to each other.
The bolt body, firing pin, barrel threads and chamber should be completely in line with the centerline of the bore.? The action lug recess, bolt lugs, bolt face, receiver face and barrel shoulder need to be 90 degrees to the centerline.? The bolt lugs and action lugs should make full contact on all locking surfaces.? The action threads and barrel threads should make full contact on the bearing surface of the threads with no contact between the top of the barrel thread and the bottom of the action threads. The chamber should be a size to precisely fit the cartridge case.
The shape or angle of the crown makes practically no difference as long as there are no burrs or irregularities in the crown and that one side of the bullet doesn't clear the barrel before the opposite side of the bullet does.? In other words, the barrel doesn't need to be longer on one side than on the other.
Why, you may ask does all this concentricity and 90 degree stuff make any difference?? The sole purpose is to launch a bullet precisely centered in the bore straight down the center of the bore and out the crown with as little wobble as possible.? If the bolt face is at 90 degrees to the chamber and the barrel bore, some of the relationships in the receiver don't have to be perfect and still you will obtain peak accuracy.? The thing is that it is far easier to obtain a bolt face perfectly at 90 degrees to the chambered barrel if every other part is in its proper relationship within the receiver.
An oversize chamber can ruin all your best efforts at building a tack-driving rifle.? The oversize chamber will allow the cartridge to lie in the bottom of the chamber and throw the bullet out of alignment with the bore.? Why then do benchrest shooters get such good groups when they are fire-forming brass?? The necks of their cases are turned to such close tolerances that the bullet is still in alignment with the bore as well as the case head is still supported by the chamber.
I haven't mentioned anything about barrel quality.? I have used barrels from most of the top makers of benchrest barrels and have had high quality barrels from all of the makers that I have used.? If you are going to economize on building a custom rifle, the barrel is not the place to do it.? Stick with a top maker and it's hard to go wrong.
Good triggers are critical for the accurate rifle.? Not that it is necessary for peak accuracy, but that it makes peak accuracy easier to obtain.? Two-ounce trigger have their place in the accurate rifle.? That place is on target rifles.?? With practice a two-ounce trigger can be squeezed and released if wind conditions change, but only if they are being shot from the bench.? Two-ounce triggers and field conditions don't mix.? I once had a two-ounce trigger mounted on my .280 deer rifle.? I was watching a coyote come into a windmill at 300 yards.? I placed my crosshairs on him and had a dead coyote.? Only thing was, I wasn't ready to shoot yet or at least, so I thought.? I replaced that trigger that day with a two-pound trigger and haven't used a two-ounce trigger on a hunting rifle again.
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