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Posted: 6/25/2006 6:48:31 PM EDT
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I shot my Colt HBAR today and ran into a problem. After having a few groups that were sort of large, but round, I started to get stringing. They were mostly vertical but leaned to the right a little. This rifle has a Simmon's 6.5x20 AO scope and a Harris bipod. It has the stock handguards, and is a postban. A fellow Arfcommer was at the range and suggested trying sandbags to eliminate the bipod as a cause. I still got a string using the sandbags. I shot some Winchester 55gr and some surplus LC 55gr made in '69. Both had stringing, but like I said the stringing started after several other groups. Something has apparently loosened. I think I eliminated the bipod. To eliminate the scope/mounts I plan on installing the stock rear sight/carry handle and shoot for groups again. Does that sound like a plan, or am I missing something? Jim |
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its been along time, but i had a bolt gun that was doing the same thing and i could never figure it out. checked everything out ,made sure everything was tight and it was. finaly talked to a bench shooter and was told that the barrel was probaly getting hot. the next time out i slowed down my firing and it helped a little, but problem still occured slightly. ended up trading the gun for a AR, so i never got to mess with it anymore. maybe should've slowed down some more. AR out |
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It sounds like breath control. Generically speaking, lateral movement is trigger control and vertical movement is breathing. The large round groups were you getting the feel of the trigger and taking the shot at different points during respiration (this lifts and lowers the barrel). You got the feel of the trigger but you continued to shoot at random points in respiration. So, the lateral deviation diminished and the vertical deviation continued. Hope this helps. JK |
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The stock trigger is a heavy POS- lots of creep and a very heavy pull. As for breathing, I have shot smaller groups with a Swedish M38 Mauser and a Swiss K31- both of which have small iron sights. I can see my heartbeat moving the scope crosshairs, especially at 20x, and I tried to fire between heartbeats. I take a breath, let about half out and hold the rest. If I don't get the crosshairs settled down before I need to breathe I just wait and do it again. I was not firing fast, and was shooting 5 rounds at a time, reloading for a 10 round group. The stringing continued even with the reload, and looking through a spotting scope between 5 round strings. There was a break/cease fire between the large round groups and the stringing groups. If it was a wood stock I might think pressure on the barrel from the forend, but the AR doesn't have that problem. Jim |
And leave the scope and bipod on until then, or go ahead and remove the bipod and put the iron sights back on and try it again myself? Jim |
| I would bet it is not the rifle, like stated before, inconsistant cheek weld or breathing. Some days I go shoot and I cut X's all day long, and some days I go shoot and I cant keep from stringing, and that can vary with me from rifle to rifle also, but I know it is me and not the rifle. In my experience most shooters are not humble enough to admit when they are at fault and will blame their misfortune on everything from the humidity to the gravitational pull of the moon. Not saying your a bad shot as it sounds like you are pretty good, just giving you my thoughts on it. Good luck. |
Try letting ALL the air out, then hold. For me, I find it easier to know when I'm completely exhaled. Plus I'm more relaxed, and am not trying to hold air in. |
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As long as everything checks out tight and secure, then I'd guess that it could be an ammo effect. Remember that each time you fire the gun, some heat gets added to the barrel. When you chamber the next round, it sits in the chamber and absorbs some of that heat. When you fire a round that has been heated up, it shoots faster, and prints higher on the target. Then, when you fire the next round after that, the barrel is a little hotter again, so then it all happens again. Competition shooters don't allow any cartridges to sit in a hot chamber for any length of time before firing, if they can help it. Hope that helps. |
| The vast majority of the time, this is a breathing issue. That doesn't mean that it can't be ammo, check weld, or alignment of the stars, but its usually breathing. That you don't usually do it is a good thing, and we all regress from time to time. Its nothing I would worry about, but remember to concentrate on the basics/ fundamentals of marksmanship the next time you hit the range. |
Practice dry fire with a penny. Balance a penny on the barrel and practice the release of the shot when all your air is completely out. It takes some practice, but it will help your off hand shots also. Not a great practice for the bench over all, but it will help with the breathing and fire control, and it is cheap. Great to do on a rainy day when you are unable to get to the range. Just pic a small spot on a wall and practice. Good luck!
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Therein lies the problem. While you are holding your breath, trying to be consistent, you aren't. The amount of air changes every time, because you have no accurate measure of where you are holding your breath. If you could measure the amount of breath you are holding, one time it would be 1 liter (or whatever unit of measurement you want to use); the next, .8 liters. The way I teach my Boy Scouts is take one deep breath, exhale completely and then try to get your sight picture. This reduces the variable amount of oxygen in your lungs. Likewise, you might need to re-evaluate your position, especially if your heartbeat can be seen/felt through your scope. Try moving your body so you are resting as much as possible on your muscles. BTW was this from the bench or the prone? |
This was sitting at the bench, using a bipod and later sandbags. It's a concrete bench, and I place a carpet remnant on it. This is really bugging me. I shot a pistol bullseye match this evening- one hand at 50 yards, using the same breath control. I shot a 752 out of a possible 900. Not great, but it was the first match I have fired with one hand- and there is a reason I have used 2 hands the last 30 years. I will do a lot more practice before I change anything. I was mostly curious about whether there was something specific that may have become loose causing this. I will work on breath control and see what I can do. I may have just had a bad day. Jim |
A FF tube is in my fiture, as is a decent trigger. What's funny is that breathing technique works for me when I shoot either my Swiss K31 or swede M38 using iron sights. I swear that I can shoot smaller groups with those using irons than I did using this rifle and a scope. Oh well. I'll get more time on this rifle before I start to panic. I am tempted to sell this Colt and buy a RRA so I can get a trigger I like easier. Jim |
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I can do that, or buy a Jard, etc. The problem with this Colt is that it has the sear block as well as large pins. It isn't a serious problem but it is annoying to pull a trigger on another rifle then find out it won't work on mine. A friend I met at the range has a trigger he was going to sell me, but it wouldn't fit. This is mostly just bellyaching. I'm not really in trouble- I just have some details to work through. That's half the fun! The only real problem I have is figuring what I need most/first. I need a trigger, FF tube, and I don't remember what else. I think the trigger needs to come first. I'm getting a cramp in my trigger finger from mine. Jim |
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RRA 2 stage trigger I am sure any dealer can get them for you too. |
| Well, everyone's already made most of the same comments I would make, but once breath control is accounted for, think again about your cheek weld. Compared to "standard" type rifles (garand, etc), the stock on AR15's can make it hard to be sure that you're placing your face in the exact same position each time you shoot. You could be moving your face slightly forward or back with each shot. You might try putting a piece of tape on the stock as a reference point to cure this, or you could use the "nose to charging handle" method. Of course, if you do this, you'll have to have your scope mounted well forward. Hope this helps... |
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fwiw... I had a scope mount work loose once, & I got vertical strings... Also, me & my buddy tried the cheap Colt knockoff scopes several years ago, & we pitched the scopes when we realized that we could shoot better groups with the irons. I think it's your scope mount, but irons will help to confirm that it's not the rifle or ammo. Good Luck! Johnny C! |
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I may try the irons to see how that works. The cheek weld issue may also be it. The relief on this Simmon's scope makes me search for the proper relief. If I shoot well with irons, but can't get the scope working, I may just stay with irons or go to a reddot. Jim |
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