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Posted: 5/14/2011 7:59:50 AM EDT
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My WOA 18"spr barrel has a habit of placing the first round out of the magazine 1 1/2 - 2 high of the group. This is not the first round out of a clean barrel , and not a stone cold barrel. If I shoot a 5 or 10 shot group the first shot that is placed in the chamber by hitting the bolt release on a full magazine will shoot 1 1/2 - 2 " high of the group . After waiting a few minutes for the barrel to cool the 1st shot in the next group does the same thing.
Can someone with more knowledge than me explain this ? |
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Cold bore shots are usually off slightly. Bore doesn't need to be clean or "stone cold" for the metal to be cooled enough to contract. When I competed in small bore, the first three shots I would take would be off the target before I sighted in just to warm up my barrel. It is just part of the physics of shooting. The suggestion to put one into the dirt before shooting for groups is not a bad one. Not good combat habit, but I assume that your rifle's primary purpose is shooting for groups on a range, as that is the purpose of most people's AR-15s.
Edit: grammar. |
| I haven't run into this problem with my AR-15 but Ruger 10/22 rifles often have an issue like this. It has been explained to me that the difference in the energy of the bolt seating the cartridge is the probelm. One of my 10/22s does this and I just fire the first shot at something else before shooting for groups. I have never heard of this issue on a centerfire though. Does it do the same thing with different magazines? |
| This is very common...and it is not anything mechanical. It is known as "first shot, last shot syndrome." When you fire your first round of the group. you have not yet "settled in" behind the rifle, so you are not using the same position/hold/cheek weld/sight picture as you are after the first shot breaks. After that, you relax into rifle, and the group goes where you want it. (I am sure lots of people will chime in about how this happens to them and they NEVER do ANYTHING less than PERFECTLY with their rifles, they spent 116 years on the Marine Corps Rifle Team, and it MUST be some esoteric trick of physics, or the density of the barrel steel, or the chamber reamer, etc etc.) But it's just a simple, very common shooter error. If you are not having the same problem on the LAST shot, too, you are ahead of the game. If you are able (by which I mean, you have a home range where you can control access to the rifle), try this: load a mag, chamber a round, fire a 5-shot group. Safe the weapon, but LEAVE IT LOADED and charged. Walk away for ten minutes. Come back and fire another five-shot group. You will probably see the same phenomenon. |
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Try shooting your first round in the dirt, then start shooting for groups. Evidently, you and I are the only people on this site that understand this method. 
For those that cannot understand the logic in the above solution, or would prefer to not waste a round into the dirt, you could try the following. Simply reverse the order you fire your shots. Shoot the last round first, then the others, and save your first shot for last, that should cure your problem....<><....:) |
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As unclejack mentioned above, I found that when I was having this same issue it was my position.
I was shooting from the bench and not getting solidly behind the rifle until after the first shot. When I moved to prone, I wasn't seeing the same issue because I could get a solid position from the start. I'm not saying it's not the rifle, but when I had this happen a position change eliminated it. |
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Mechanically it can happen more often with rimfire. Thats another story. -
Cold bore 'fliers ' are sometimes cold shooter. Mechanical gremlins can be tougher to trace. Try the cold shooter approach first and see where you get. Mechanically, I would look at the muzzle device and its mounting / tightness. As for throwing the first round, don't. Always make it count and learn your rifle. |
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Try shooting your first round in the dirt, then start shooting for groups. hehe thats funny, but honestly OP that makes no sense, i have never heard of anything like that actually happens a good deal of time, even bolt guns. I shoot fur and a few others around here do also. A first round flier is usually a rifle or barrel or upper that gets sold or traded quickly. You never want a first round flier. 1 in. high @ 100 = 3 inch high @300. 5 inches@500, ect,ect I have a few that will be high on the first shot by .3-.5 out of a cold fouled bore and hold accordingly. I have cut loose a many rifle,barrel,upper that threw fliers! I know it sounds funny to some around here but that 1st shot is the most important to a hunter. |
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I was taught that a barrel with oil in it will always shoot high (A clean Barrel in other words). You take a foul shot first to stop this. ( LIke mentioned in a previous post).
Room Temprature Barrels do not affect accuracy. Hot Temprature Barrels will affect accuracy. Almost all professional snipers after cleaning their gun will take a foul shot and store the gun dirty. (They can't take a foul shot out in the field always). |
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I know it sounds funny to some around here but that 1st shot is the most important to a hunter. especially if you are hunting 2 legged creatures that have firearms pointing back at you. get rid of the barrel. first shot flyers will get you hit. what. What, you mean all the soldiers (armorers) dont switch out all that barrels that throw first round fliers for all the soldiers that shoot them? secondly, if a 3 in. variation on the first shot at 300 yds means u die in combat cause u did not hit the bad guy, you got bigger problems....a person is at least 16 inches wide if not wider. |
| well i guess if you dont want to hit what you aim at, then its no problem. i like to hit my mark, the target i use at 100 yards is only 6" in diameter. from the center line, to the edge is only three inches. looks to me like the first round would be a miss. maby not on a human (hopefully) but accuracy counts allways. first shot or not. just my opinion. call me ignorant, but i like to hit what i aim at. kinda makes me feel good. |
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I know it sounds funny to some around here but that 1st shot is the most important to a hunter. especially if you are hunting 2 legged creatures that have firearms pointing back at you. get rid of the barrel. first shot flyers will get you hit. what. What, you mean all the soldiers (armorers) dont switch out all that barrels that throw first round fliers for all the soldiers that shoot them? secondly, if a 3 in. variation on the first shot at 300 yds means u die in combat cause u did not hit the bad guy, you got bigger problems....a person is at least 16 inches wide if not wider. First, after walking several kilometers and sprinting about with about 150lbs of shit on in some stupid climate, it will prolly take me a few rounds to hit something at 300 meters and I consider myself decent with my issued carbine. That 300 meter target will more likely be engaged by a gun team (240/249/203) or an SDM. Not saying that I wouldnt be firing at it either way. Second, when will the shooters benchrest rifle be in the aforementioned prediciment? If the shooter sees himself engaging in HD at 100 meters plus, he may want to invest in a new system. Otherwise, I think that 2 inches off still places just fine on an E-Type at that distance and under. At south of 25 meters, you dont even need to use anything but the FSP to aim. South of 10 you dont even need that. Im sure his bbl will kea hole in someone just fine. ETA: I may have missed the sarcastic point of your post. lol, carry on. |
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Quoted: Try shooting your first round in the dirt, then start shooting for groups. Thats how you get .25" groups at 100, throw out all the bad and only count the good.  Dirt shooters do this It does happen with some rifles and has been documented by "experts" on this board. What causes it is unknown. My guess is its how the bolt hits the round when released from the BCG, vice during recoil and how "tight" its chambered. I have one rifle that will do it, cold/clean/ doesnt matter, the 1st round from the mag is high. The good thing its measurable and you can compensate for it. |
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Quoted: I think you descibe one type of problem, but its not 100% across the board. I have tried your trick of splitting a mag, and also have had other shooters shoot the rifle, same thing.This is very common...and it is not anything mechanical. ....snip There is a diffference in how the first round is chambered, and some rifles that can make a difference, I think most dont know it becuase probably less than 10% of people will take the time/effort to shoot groups small enough to notice it. |
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I think you descibe one type of problem, but its not 100% across the board. I have tried your trick of splitting a mag, and also have had other shooters shoot the rifle, same thing.
This is very common...and it is not anything mechanical. ....snip There is a diffference in how the first round is chambered, and some rifles that can make a difference, I think most dont know it becuase probably less than 10% of people will take the time/effort to shoot groups small enough to notice it. +1 I have not encountered this in the centerfire AR platform I have in a few rimfire 10/22's. I found that excessive headspace was the problem, reducing headspace closer to the minimum of .0485 reduced to problem. |
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Not mentioned here yet it seems, but another option is you simply log it, then when you take your first shot you know where it's going to go. I know, I know... it sounds so simple!!! :P YEP. Thats the way it's done. Though any barrel,upper, rifle pitching a 1st round out from a cold fouled bore 1-1.5@ 100 yds. does'nt last in this house.and I suspect in others. Shooters have differant needs. Theres a good deal of differance between center mass on 2 legged creatures and a groundhogs head at 250-300 yards. 
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If you know exactly what it does every single time, just adjust accordingly. Aim 1.5 to 2 inches low for that first shot. Just as you would adjust for wind or elevation difference. either that or shitcan it you don't really think either of these 300 RUM barrels will live in this house if they pitch the 1st round out at 1moa @100
they will be fancy tomato stakes and someone won't get anymore bussiness Then again I know they'll shoot 99% sure
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| I think every m4 I have sighted in has had the first shot flyer. In less the barrel is in the sun or warmed up all barrels will have a slight point of impact shift to some point. Thats why MOA guaranteed guns like weatherby or the like will say cold bore shot. This is why you should shoot a grouping first before sighting in a weapon (basic skills). People are blowing smoke with the trash it theory and need to do some random grouping when they go to a range. M4's and m16 are 3 to 6 MOA rifles a sub moa rifle with a more consistent action and rifling will probly have less shift than a gas operated system. Dry cycle the action some to take some of the setup out of the buffer for better bolt lock up but again after your first few rounds your bolt will heat up to. |
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I think every m4 I have sighted in has had the first shot flyer. In less the barrel is in the sun or warmed up all barrels will have a slight point of impact shift to some point. Thats why MOA guaranteed guns like weatherby or the like will say cold bore shot. This is why you should shoot a grouping first before sighting in a weapon (basic skills). People are blowing smoke with the trash it theory and need to do some random grouping when they go to a range. M4's and m16 are 3 to 6 MOA rifles a sub moa rifle with a more consistent action and rifling will probly have less shift than a gas operated system. Dry cycle the action some to take some of the setup out of the buffer for better bolt lock up but again after your first few rounds your bolt will heat up to. well. most of my barrels are HBAR or Bull style, SS/CM non C/L. Also 2 are WOA barrels. Out of cold foulded bores they won't pitch the 1st round no more than .5-.6@ 100 YDS. and it's always high. These are all "weighed, not dropped charges" handloads for that particular rifle and a front rest and bagged rear and trigger work. I do own M4 and carbine uppers, I own these for other reasons than hunting,target work. Heres a cheap 20" WOA barrel build,RRA 2 stage, cheapo smooth side DPMS upper, Armalite mount, Millet TRS 4-16. It does as it should with a cold fouled bore from a solid rest  that's if I do my end.
If I had and AR throw'n the 1st round out a ways I'd change my handloads. Powder type would be the 1st. Actually believe it or not I've had more problems with bolt guns than AR's Bedding, action screw torque usually square them away. Ya just got to work with your loads OR your shooting. 
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Try shooting your first round in the dirt, then start shooting for groups. Evidently, you and I are the only people on this site that understand this method.
I learned to shoot in the British Army we always shot warmers into the bank before Grouping. (Warmers into the bank are also beers in the Mess before hitting the town )
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| now the poster menchened it was the first shot when he released the bolt hold open this might be more than just a cold barrel. You may have a weak buffer spring that is not allowing the bolt to full seat try using the charging handle by pulling it all the way to the rear then release it allowing the extra energy to strip the round and set the bolt or hit the forward assist. After the first shot the gas and recoil pushes the bolt back with a lot more pressure and the rebound is setting the bolt in the chamber as it should. If this helps try a new buffer spring and maybe a heavier buffer. |
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now the poster menchened it was the first shot when he released the bolt hold open this might be more than just a cold barrel. You may have a weak buffer spring that is not allowing the bolt to full seat try using the charging handle by pulling it all the way to the rear then release it allowing the extra energy to strip the round and set the bolt or hit the forward assist. After the first shot the gas and recoil pushes the bolt back with a lot more pressure and the rebound is setting the bolt in the chamber as it should. If this helps try a new buffer spring and maybe a heavier buffer. you'll always get that out of a autoloader. Especially an FAL. It sure should'nt be 1.5" out at 100yds for an AR platform. Doin this over the net is hard to say. All my accuracy rifles have a pretty fine crosshair reticle scopes ,decent trigger and loads to match the rifle. Honestly any AR that could'nt hold 2 in. groups on a solid rest,bagged with a decent scope and top quality loads I'd have to look at the barrel or my shooting form? I have a few good shooters, non free floated and off a rest do very well. these AR's will perform better than any selfloader I know of? |
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Sounds to me that maybe this barrel was not properly "stress relieved". This does happen.
This article has some info on barrels and stress from manufacturing. http://www.rifleshootermag.com/gunsmithing/RSgunsmith1/ Talk to the manufacturer, they may make it right. |
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