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Thread: Semi-Auto VS. Bolt Action Accuracy

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    Moderator hunt_ak's Avatar
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    Arrow Semi-Auto VS. Bolt Action Accuracy

    I've always heard that a bolt action is more accurate than a semi automatic action but have never really understood why it would be. Once the round was chambered it would seem it wouldn't make too much of a difference. Anyone know the mechanics/engineering behind why one is more accurate than the other?

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    Moderator Paul H's Avatar
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    It isn't a hard and fast rule and comes down to the tollerances the gun is built to. In general, semi autos will have slightly looser tollerances to allow everything to function without hanging up.

    With that said, there are very accurate semi autos, and innacurate bolt guns.

  3. #3

    Default Maybe

    While not an expert, I have found that if you want the best accuracy out of an auto loader you need to be very ammo selective. The best ammo for them seems to be bullets with polymer tips, small hollow pounts (like sierra gameking and matchking bulloets) and ball. The tips of the lead projectiles tend to shear off small pieces at angles when forced into the chamber at high speeds and under force causing a slightly erratic bullet bullet flight. The bullets that perform the best don't offer the rifle the oppurtunity to damage bullets in this way. That's why Remington came out with a proprietary bullet for auto loaders and pumps, the BRONZE-POINT. I've never been able to acheive consistant groups of less than 1 MOA with them and as a result don't use them, but they do tend to function well in most autos.
    These observations are from years of shooting Remington autos. I've never had the oppurtunity to do much shooting and load developement for other style autos except Garands and M1 A's. IMO they're just a little heavy for field sporting use, but shoot NRA high power well.
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    Member Alaskacajun's Avatar
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    Ditto what bravO1 said.....

    I'll add that you can't usually seat the bullet near the lands in an autoloader, like you can in a bolt gun.

    - Clint

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    Back when I was on active duty I once won a target match with an M-14 by turning the gas selector screw to the grenade launcher mode. (turned it off)
    So I had a straight pull action. The bullet impact went up just a touch at 300 meters. It may have been from the fact that no gas was being bleed off or maybe there was as light bit more recoil.
    Anyway, it was very consistant and my score jumped up.
    Floatplane,Tailwheel and Firearms Instructor- Dragonfly Aero
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    http://site.dragonflyaero.com

  6. #6

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    I perfer bolt action because of accuracy, weight and handling. In reloading I have found tolerances are closer in bolt action than in semi-auto.
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    Quote Originally Posted by hunt_ak View Post
    I've always heard that a bolt action is more accurate than a semi automatic action but have never really understood why it would be. Once the round was chambered it would seem it wouldn't make too much of a difference. Anyone know the mechanics/engineering behind why one is more accurate than the other?
    While it may be the case with automatics versus bolt guns in general, you can't say that anymore.

    Some of these AR type rifles are extremely accurate. Mike Venturino wrote an article in the latest Handloader magazine, where he tested one (Rock River A4) along side a Savage 11F. It was every bit as accurate as the bolt action Savage, with all the many loads tested.
    Amazing
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    Moderator hunt_ak's Avatar
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    So basically you're telling me, the higher quality the autoloader the better accuracy your going to have and then it really doesn't matter wether it be a semi-auto or a bolt action....Am I correct in saying that?

  9. #9

    Default Don't Know

    The long range and 1000 yard matches are being dominated by the auto rifle world. The militaries have gone semi and full auto MBR's and with modern tecnology the weight of semi's is now equal to or less than that of bolt guns.
    The main drawback of semi's is they tend to catch more flak from the antis than bolts, NOW. Divide and conquer.
    Accuracy is no longer a problem with auto regardless of what your daddy my have told you. The days of well used garands and FN 49's has passed. The new auto can and will hold there own against most any comprable priced and caliber bolt gun.
    Does everyone want or need a semi auto, NO. But there are several great reasons to own them. They have less recoil and don't require you divert your attention to working your bolt while trying to get a follow-up shot. This also allows people of smaller stature (kids, women, small framed people) to enjoy the outdoors as well.
    Are they as reliable, depends on the operator. If you've ever been in the military, remember what your DI told you, THIS is your best friend in the whole world take care of it. Semi's take a little more care and some people aren't willing to put out the effort.
    Just auto pistols and revolvers, personal preference.
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  10. #10

    Talking lead tips

    Someone did a study, using hi-speed photography, that showed the lead tips melt away on bullets fired at over 2800fps. They bent, smashed and cut them off and found it made no difference in accuracy at all, according to what I read. Also, I think Remington made the bronze point to facilitate faster expansion upon impact, again, according to an article. Murphy would surely know.

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    Moderator Paul H's Avatar
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    Quote Originally Posted by hunt_ak View Post
    So basically you're telling me, the higher quality the autoloader the better accuracy your going to have and then it really doesn't matter wether it be a semi-auto or a bolt action....Am I correct in saying that?
    Not exactly, if you compare top notch of both offerings, the bolt guns will still come out on top. I've yet to hear of a semi that will print as well as a purpost built bench gun, ie 0.1" to 0.2" groups at 100 yds. Bolt guns allow one to run tighter tollerances and still function, and allow much more flexibility with reloading. There are also less options as to what chamberings you'll find in an auto.

    But if you're looking at off the rack autoloaders for hunting, you'll find that they offer accebtable accuracy if that's the sort of action you prefer. If I was after varmints and wanted the option of multiple hits, I'd be hardpressed to pass up a good AR15. If I was hunting the mountains, I've yet to see semi that offers the same package as a Kimber Montanna 300 WSM.

  12. #12

    Default Study

    Quote Originally Posted by Maydog View Post
    Someone did a study, using hi-speed photography, that showed the lead tips melt away on bullets fired at over 2800fps. They bent, smashed and cut them off and found it made no difference in accuracy at all, according to what I read. Also, I think Remington made the bronze point to facilitate faster expansion upon impact, again, according to an article. Murphy would surely know.
    I haven't seen such a study. I would be interested in it though. The only information I have is what I have gleened at the shooting range over the years using bolt and auto-loading rifles. I do know however if I single load my Rem 742 in .243 with Federal 80 bullets it will shoot around 1/2 an inch. If I let it feed from the magazine, the group opens up to around an inch. The difference, I have noted is the rifle usually damages the lead tips as it loads from the magazine. I now use 75 BTHP bullets in this rifle with great results.
    As far as lead tips melting off of bullets where does it go? If a bullet achieves 4000 FPS it would melt in the barrel once it a reached that speed. I have had bullets disentagrate in flight however from excessive velocities.
    " Americans will never need the 2nd Amendment, until the government tries to take it away."

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  13. #13

    Default Maybe

    Quote Originally Posted by Paul H View Post
    Not exactly, if you compare top notch of both offerings, the bolt guns will still come out on top. I've yet to hear of a semi that will print as well as a purpost built bench gun, ie 0.1" to 0.2" groups at 100 yds. Bolt guns allow one to run tighter tollerances and still function, and allow much more flexibility with reloading. There are also less options as to what chamberings you'll find in an auto.

    But if you're looking at off the rack autoloaders for hunting, you'll find that they offer accebtable accuracy if that's the sort of action you prefer. If I was after varmints and wanted the option of multiple hits, I'd be hardpressed to pass up a good AR15. If I was hunting the mountains, I've yet to see semi that offers the same package as a Kimber Montanna 300 WSM.
    Thoose special built bench guns are not field capable nor are they in sporting calibers and are single shot configurations. Most have the loading port on the left and the bolt on the right or vica versa.They weigh from 10 1/2 lbs to 100 lbs. and use fixed 16-36 power scopes which aren't field capable either.The ammunition is loaded on site with the use of laptop computers and field notes for the day. NOT very practical in the field. Most shoot ammunition the names of which you can't spell or even find brass for.
    As for cartridge selection check the Benelli R-1, it's available in 300WSM if that's your favorite caliber and is very close in weight and size to your Kimber Montana, with less recoil. As for beauty thats in th eeye of the beholder.
    " Americans will never need the 2nd Amendment, until the government tries to take it away."

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  14. #14

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    The first target is the best I could get out of a 30-06 750 Rem semi-auto and this is not bad at all and it was with factory ammon I was not able in my handloads to beat this with this rifle.



    this next group was shot out of a savage 116 7mmSTW and it speaks for it's self.

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  15. #15

    Default Nice

    Those are indeed very nice groups and would work well, under any field requirements.
    " Americans will never need the 2nd Amendment, until the government tries to take it away."

    On the road of life..... Pot holes keep things interesting !

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    Quote Originally Posted by brav01 View Post
    Thoose special built bench guns are not field capable nor are they in sporting calibers and are single shot configurations. Most have the loading port on the left and the bolt on the right or vica versa.They weigh from 10 1/2 lbs to 100 lbs. and use fixed 16-36 power scopes which aren't field capable either.The ammunition is loaded on site with the use of laptop computers and field notes for the day. NOT very practical in the field. Most shoot ammunition the names of which you can't spell or even find brass for.
    As for cartridge selection check the Benelli R-1, it's available in 300WSM if that's your favorite caliber and is very close in weight and size to your Kimber Montana, with less recoil. As for beauty thats in th eeye of the beholder.
    There are purpose built guns that are VERY field capable - more so than any standard hunting rifle on the market - Look at some of the Custom work by GA Precision - Tactical bolt action rifles that are capable of 1/4 MOA. Yes, they weigh more than a normal hunting rifle - But if you can pack an animal out of the woods, I'm sure you can handle a 15-18lb weapon?

    When comparing semi's to bolts you also need to compare the costs of each. One previous post stated they compared a RRA AR to a Savage 11F - Thats comparing a $1,000 (estimate) to a $400-$500 gun - Big difference there.

    Fact is for a semi auto to compete, its gonna cost money. But then again, fact is at the end of the day theres no semi-auto that will out shoot a comparable bolt action.....

    Besides....most guns can shoot better than the majority of the people handling them so its sort of a moot point..

    I personally hunt with one of these "smithed up" bolt actions, based on a remington 700 action, gun weighs in at about 16.5lbs without scope or anything on it...Love it, offers a very steady offhand shot.

  17. #17

    Default Accuracy

    Quote Originally Posted by OneLunG View Post
    There are purpose built guns that are VERY field capable - more so than any standard hunting rifle on the market - Look at some of the Custom work by GA Precision - Tactical bolt action rifles that are capable of 1/4 MOA. Yes, they weigh more than a normal hunting rifle - But if you can pack an animal out of the woods, I'm sure you can handle a 15-18lb weapon?

    When comparing semi's to bolts you also need to compare the costs of each. One previous post stated they compared a RRA AR to a Savage 11F - Thats comparing a $1,000 (estimate) to a $400-$500 gun - Big difference there.

    Fact is for a semi auto to compete, its gonna cost money. But then again, fact is at the end of the day theres no semi-auto that will out shoot a comparable bolt action.....

    Besides....most guns can shoot better than the majority of the people handling them so its sort of a moot point..

    I personally hunt with one of these "smithed up" bolt actions, based on a remington 700 action, gun weighs in at about 16.5lbs without scope or anything on it...Love it, offers a very steady offhand shot.
    As a forner benchrest shooter and prairedog hunter,I agree that bolt guns offer the capability to provide excellent accuracy. And unlike some shooters I wouldn't compare a Savage to a Stohl Panda. Most rifles are capable of accuracy that exceed the shooters abilities.
    I realize there are hundreds if not thousands of sheep and goat hunters who would line up to carry an 18 pound rifle into the mountains in pursuit of their quarry. I myself prefer a rifle in the 6 1/2 to 8 pound range.
    As for there being no auto capable of accuracy equal to a bolt gun that's not all together true...! David Tubbs the 11 time World Champion High Power Rifle shooter shoots a modified AR-25 type rifle. From all three positions prone, kneeling and standing he averages 1 MOA or less with open sights not off a bench or bipod. He competes with world class shooters who may use ANY high power rifle including bolt guns. I'm sure his rifle will equal the accuracy of an equal weight bolt gun with the same sighting system. High Power rifle is shot at 600 and 1000 yds.
    " Americans will never need the 2nd Amendment, until the government tries to take it away."

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  18. #18

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    Quote Originally Posted by brav01 View Post
    As far as lead tips melting off of bullets where does it go? If a bullet achieves 4000 FPS it would melt in the barrel once it a reached that speed. I have had bullets disentagrate in flight however from excessive velocities.
    Some 17s and the 204 Ruger exceed 4000fps. I've often wondered if bullets came apart at high velocity because they were shot fast or because they spin themselves apart. Ruger 204's have a twist rate of 1 in 12". Once a foot. At 4200fps spinning once per foot you get 252,000RPM. That's a lot of stress on a bullet even considering it's minute size.
    Quote Originally Posted by Maydog View Post
    Someone did a study, using hi-speed photography, that showed the lead tips melt away on bullets fired at over 2800fps. They bent, smashed and cut them off and found it made no difference in accuracy at all, according to what I read. Also, I think Remington made the bronze point to facilitate faster expansion upon impact, again, according to an article. Murphy would surely know.
    Wow, that is interesting. The weight of the bullet and the diameter will effect how much heat is generated by drag and absorbed in the core and jacket. I wonder if they were using light for caliber bullets?
    Quote Originally Posted by OneLunG View Post
    There are purpose built guns that are VERY field capable - more so than any standard hunting rifle on the market - Look at some of the Custom work by GA Precision - Tactical bolt action rifles that are capable of 1/4 MOA. Yes, they weigh more than a normal hunting rifle - But if you can pack an animal out of the woods, I'm sure you can handle a 15-18lb weapon?

    When comparing semi's to bolts you also need to compare the costs of each. One previous post stated they compared a RRA AR to a Savage 11F - Thats comparing a $1,000 (estimate) to a $400-$500 gun - Big difference there.

    Fact is for a semi auto to compete, its gonna cost money. But then again, fact is at the end of the day theres no semi-auto that will out shoot a comparable bolt action.....

    Besides....most guns can shoot better than the majority of the people handling them so its sort of a moot point..

    I personally hunt with one of these "smithed up" bolt actions, based on a remington 700 action, gun weighs in at about 16.5lbs without scope or anything on it...Love it, offers a very steady offhand shot.
    Bolts are a lot simpler than autos. Of course they are cheaper. These purpose built guns you talk about probably cost a lot of money. How much does yours "smithed-up" gun cost compared to the RRA AR?

    In theory if both guns shoot equally consistant ammunition they both have the ability to shoot equally well. In reality, variations in ammunition effect a bolts POI much less than autos.

    The weight arguement is more complicated than someone being able to haul an 18 pound gun around. If someone is unwilling to tote almost 20 pounds then it is an issue. It is a gun that has no capability for that person. I can cover a lot more ground with a 20 pound load than I can with a 30 pound load. That extra ground translates into more opertunities for the hunter. An 18 pound gun is less capable at hunting than an 8 pound gun.

    Does a hunter need 1/4MOA accuracy to be successful? Does 1/4MOA accuracy make a rifle and hunter more capable? Can you shoot 1/4MOA from imporvised positions? Can you shoot 1/4MOA offhand? Are your hunting bullets capable of shooting 1/4MOA? You also said, "besides....most guns can shoot better than the majority of the people handling them so its sort of a moot point."

    In capability let's not overlook the autoloaders advantages. Depending on the size of the magazine you can have 9, 19, 29, 99 extra shots on demand without manually cycling the action. Recoil is also disipated by the action utilizing recoil energy. How many bullets fit in your typical bolt gun magazine? Provided both guns are well maintained dependability isn't an issue.

    Last I checked your average bolt guns accuracy has gone down over the last decade. Some manufacturers are letting guns go that will only shoot 2 MOA. Go grab a non-blowback new autoloader and a bolt gun I wouldn't be surprised if they shot about the same. To be made to shoot 1/2-1/4 MOA any average gun needs work be it autoloader or bolt. At entry level the auto's may cost a few hundred more dollars but once you start accurizing that few hundred dollars means less and less.

    The question which shoots better, I would probably say the bolt. Less variables to manage. However, given high levels of precision the margin could be run down to almost nothing. Given frequent cleaning of the guns, which is normal anyway in high precission shooting, variation in the cylcing mechanism due to fouling could be mitigated. This is the primary source of variability in autos that isn't present in bolts. I believe it would come down to who is the better shooter rather than which action is better.

  19. #19

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    Speer's website advises against using lightweight .22 cal bullets in 1 in 7 twist barrels because the centrifical force tears them apart. They recommend using 70 gr.

    I've read stuff where guys deliberately deformed exposed lead tips and it didn't seem to affect accuracy. Perhaps the combination of heat and centrifical force spin the things off to the jacket. It would be interesting to see some high speed photography of what happens down range.

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    If bolts are not consistently more accurate than why do military snipers use primarily bolt action rifles? the Cheytac Model 2000 for example is bolt action .408Cheytac rifle capable of high accuracy out to 2200meters - Or barretts new .416 Barrett - Again a bolt action.

    If semi autos were more accurate, or equal to bolt actions I'm sure most snipers would carry those instead - being able to deliever rapid follow up shots.

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