Ozzy Fudd Posted September 8, 2009 Report Share Posted September 8, 2009 i just wanted to get something clarified if possible. a while back i posted a thread asking if a semi auto rimfire has a lower muzzle velocity than a bolt, because some of the power is used to cycle the bolt and load the next round, but the main response i got was that there shouldnt be much (if any) difference because the bullet has left the barrel before the action starts to cycle. but recently i read a thread about accuracy in bolt actions vs semi auto, and i saw one or two responses saying that bolts are more accurate because the action of a semi starts to cycle before the bullet leaves the barrel im confused Quote Link to comment Share on other sites More sharing options...
guss109 Posted September 8, 2009 Report Share Posted September 8, 2009 Im not 100% sure of the facts but i shoot with a semi auto and the grouping is slightly bigger than the bolt action one i used to use but i guess you just get used to it Quote Link to comment Share on other sites More sharing options...
Billy. Posted September 8, 2009 Report Share Posted September 8, 2009 I can shoot a 1/4" group at 25 yards using my bolt action. There is no chance of being able to do this with my semiauto. I was always told you do lose energy and if you think about it, a rifle will use the energy of the bullet pushing backwards to reload, not like the gas pressure used in a shotgun. There has to be a loss of energy somewhere if this is how it reloads. Quote Link to comment Share on other sites More sharing options...
tweedledee Posted September 8, 2009 Report Share Posted September 8, 2009 tried the semi good as it was the bolt action is a step ahead.i used to like being different with a semi but now i would only use bolt action Quote Link to comment Share on other sites More sharing options...
Ozzy Fudd Posted September 9, 2009 Author Report Share Posted September 9, 2009 cheers lads sorry should have been clearer, im really looking to know if the bullet leaves the barrel before or after the bolt starts cycling? just wondering Quote Link to comment Share on other sites More sharing options...
Blunderbuss Posted September 9, 2009 Report Share Posted September 9, 2009 The bullet leaves the barrel before the bolt has moved any appreciable distance. Another reason I've heard quoted for the difference in accuracy, is that semi autos have their chambers made slightly larger, so the round is a slightly sloppier fit. This is to avoid a stuck fast empty, because the small recoil operated bolt exerts much less extraction force on the empty case than the larger manually operated bolt on a B/A. The slightly tighter chamber on a B/A results in better accuracy as the bullet is more precisely aligned with the bore. I'm not 100% certain this is a fact, but it makes sense to me. Quote Link to comment Share on other sites More sharing options...
Raja Clavata Posted September 9, 2009 Report Share Posted September 9, 2009 The bullet leaves the barrel before the bolt has moved any appreciable distance. Another reason I've heard quoted for the difference in accuracy, is that semi autos have their chambers made slightly larger, so the round is a slightly sloppier fit. This is to avoid a stuck fast empty, because the small recoil operated bolt exerts much less extraction force on the empty case than the larger manually operated bolt on a B/A. The slightly tighter chamber on a B/A results in better accuracy as the bullet is more precisely aligned with the bore. I'm not 100% certain this is a fact, but it makes sense to me. Sounds reasonable to me, and correlates well to the chambering modification of the Sako Quad .22lr barrel that GMK will perform on an FOC basis to more reliably eject unfired rounds that have been loaded into the chamber but with a resulting loss in accuracy. That said, it's not meant to be a significant degradation. Suspect the S/A chamber is "sloppier" though. Quote Link to comment Share on other sites More sharing options...
Frenchieboy Posted September 10, 2009 Report Share Posted September 10, 2009 Hi Babby, I think it might have been a thread that I posted as short whila ago titled ".22LR Semi Auto V Bolt Action" http://forums.pigeonwatch.co.uk/forums/ind...showtopic=98163 that you saw where I was asking about any possible velocity difference between the two due to the energy being used for the recycling. It was explained that the recycling starts before the bullet leaves the muzzle which could cause an "accuracy issue" but there was no significant difference in muzzle velocity! I am not questioning this as I am not a "Technical Boffin" but I find it hard to understand how there is not a difference in muzzle velocity when some of the energy is being used to operate the recycling before the bullet leaves the muzzle? I can understand how there might be a "slight" accuracy issue with a Semi Auto compared with a "Bolt Action" but I personally do not have any "seroius" issues with this when using my Winchester 290, but having said that I have not compared it with a Bolt Action .22RF, and if there are any minor accuracy issues surely this is down to how you hold your rifle while firing as there is so little recoil from a .22RF anyway! (I can shoot a 1 inch group at 50 yards with my "Winny" on a good day whcih is plenty good enough for me and I get very few rabbits get up and argue the point!) Maybe there is a "Technical Boffin" on PW that can clarify this for us please. Quote Link to comment Share on other sites More sharing options...
Bleeh Posted September 10, 2009 Report Share Posted September 10, 2009 I knew a semi .22 that seemed to cycle so fast it would scar the bullet heads agaist the inner barrel, which sent the bullets wonkey. Quote Link to comment Share on other sites More sharing options...
Ozzy Fudd Posted September 10, 2009 Author Report Share Posted September 10, 2009 Hi Babby, I think it might have been a thread that I posted as short whila ago titled ".22LR Semi Auto V Bolt Action" http://forums.pigeonwatch.co.uk/forums/ind...showtopic=98163 that you saw where I was asking about any possible velocity difference between the two due to the energy being used for the recycling. It was explained that the recycling starts before the bullet leaves the muzzle which could cause an "accuracy issue" but there was no significant difference in muzzle velocity! I am not questioning this as I am not a "Technical Boffin" but I find it hard to understand how there is not a difference in muzzle velocity when some of the energy is being used to operate the recycling before the bullet leaves the muzzle? I can understand how there might be a "slight" accuracy issue with a Semi Auto compared with a "Bolt Action" but I personally do not have any "seroius" issues with this when using my Winchester 290, but having said that I have not compared it with a Bolt Action .22RF, and if there are any minor accuracy issues surely this is down to how you hold your rifle while firing as there is so little recoil from a .22RF anyway! (I can shoot a 1 inch group at 50 yards with my "Winny" on a good day whcih is plenty good enough for me and I get very few rabbits get up and argue the point!) Maybe there is a "Technical Boffin" on PW that can clarify this for us please. hi mate, yeah im talking about that one but also this thread i posted in july - http://forums.pigeonwatch.co.uk/forums/ind...muzzle+velocity - where someone posted that the bullet is usually a couple of feet from the muzzle before the action starts cycling - i had been told the same as uyou that semi's used some of the power to cycle the bolt, which i thought would mean that they would have a lower muzzle velocity... really im not too worried about the accuracy issue/argument anymore as by the looks of things ill be getting rid of my 22lr in the next few months. it was just something that was niggling me - does it start cycling before or after the bullet leaves the barrel? (though i didnt word it the best way possible in my first post ) the bit about semi chambers being a bit looser though does make some sense Quote Link to comment Share on other sites More sharing options...
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