Group interpretation...

1stmar

New member
Guys give me your thoughts on these groups. Virtually identical. 4 shots into 1/4 in and 1 shot off to the side in the same spot on both targets. The groups look identical. I have a 3rd group that is very close as well.
 

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1stmar

New member
30-06 ruger w McMillan stock and hart barrel. Shot wide was 3rd or 4th. Load was 47 gr of 4064, 168gr smk, win primers and brass. It was windy today but seems too coincidental to be wind.
 

green_MTman

New member
if the wind was blowing to the right then that could explain the misses to the right.
shooter error would likely give you misses in a random direction.although coincidences do happen.honestly damn good shooting anyway.you still shoot better than 95% of the general public
 

1stmar

New member
I was hoping to get the 5th shot in there. The wind was blowing in that direction but distance was only 100 yards, and given the commonality between the groups I just figured it was something else.
 

noylj

New member
Besides shooter error, you can have barrel heating, bedding, change in position, parallax, wind, and a thousand other things.
 

old roper

New member
Good looking groups. have you check trigger pull with digital see how repeatable that is? Next would bedding action screw really had to say.
 

Bart B.

New member
It's been my observations that the single most common cause of horizontal shot stringing when rifles are rested atop something on a bench top is how the rifle's held when its shot. The angle between the rifle and a line between the shooter's shoulders is often not exactly the same for each shot. Which means the muzzle will point to a different place horizontally when the bullet exits. The rifle's bore axis moves a little before the bullet leaves the muzzle.

There's another cause that compounds the problem; trigger finger's not pulled straight back each time and the impact of it coming to a stop an an angle to the bore axis moves the rifle a tiny bit sideways before the round fires. Heavier trigger pull weights compound this problem.

Dry fire your benched rifle noting carefully which way the scope's reticule jumps when the firing pin slams home. If it moves any amount in any direction, you're moving the rifle off the desired point of aim before a bullet will leave the barrel when using live ammo. You'll have to keep your aiming eye open to see this happen. Learn to keep it open when firing live ammo, too. Have a friend load (or not load) your rifle where you can't see that, hand it to you then you shoot it. If it jumps a lot when the firing pin falls on an empty chamber, you're flinching and that really changes the direction the bullet leaves at; it won't be where you want it to.

I had both problems when I first started shooting for accuracy in competition. Some of the masters convinced me to quit shooting a hand held rifle holding it atop a bench and switch to a good prone position laying on the ground. That worked much better. Horizontal shot stringing stopped as my position and rifle hold was more repeatable from shot to shot.

Most interesting was when I went back to shooting a hand held rifle from a bench, shots went about 1 to 1.5 MOA to the right from zeros established shooting prone. When a couple of southpawed shooters I shot with said their benched groups went to the left from prone zeros, that turned on a light in my mind.

No wonder most benchresters shoot their rifles in virtual free recoil. They only touch their few-ounce triggers after shifting the rifle to put the sights on target where they want them. No other part of their rifle is touched by them. The rifle recoils exactly the same from shot to shot and the bullets leave the same way each time.
 

1stmar

New member
Ok sounds like no one thinks it the ammo so i can focus on my technique. It could be a bedding screw I'm inclined to believe it is me. Looks like some attention to detail and shooting position. The trigger is pretty consistent 2 1/4 or so. I do need to work on consistent trigger position and setup.
 

green_MTman

New member
use. a sand bag or soft style rest that will hug the rifle and really try to only touch your rifle with the trigger finger hand.for me this means my left hand usually does not touch the gun.
when a hard or firmer rest is used slight inperfection in the groove that hold the rifle will push the gun in the wrong direction once fired

i think Bart B. the guy a couple post ahead really made a good about minimum hand and shoulder rifle contact and the butt of the gun need only slightly caress the the shoulder,because the shoulders recoil reaction will affect the bullet.you as a right handed shooter,excessive shoulder contact could have pushed those shots right.
but dont worry your groups are still better then mine ,im way to addicted to coffee and nicoteen gum to ever see sub 2" groups at 100.you will need a heart rate at 60 to get sub moa groups
 

Bart B.

New member
I've seen such horizontal dispersion when ammo with case heads and the bolt face out of square enough to make that happen. With bolt action rifles' lugs locking at the 12 and 6 o'clock positon and the case head slamming back against the bolt face, the head impact on the left and right side of the bolt face causes a lot of horizontal barrel whipping before the bullet exits. When the bullet finally does exit, it's often to the right or left of zero. Case head impact at the top and bottom had very little effect.

What happens is the high point on the case head hits the bolt face on one side or the other first. That force point's off the center of the bore and recoil axis when all's perfect. So, that off center force transfers to the barreled action and makes it whip more in the horizontal plane.

Creighton Audette did a test proving this some years ago and an article on it was in the American Rifleman magazine, as I remember. It happened to me with my first really accurate Win. 70 match rifle; squaring up the bolt face fixed that problem. Case heads on new cases were no longer flattened out of square upon first firing. And military rifle teams' M1 and M14 rifles had the same problem but in the vertical axis. Their rifles' bolt faces were never squared up and with the lugs locking at 10 and 4 o'clock, vertical shot stringing occured when they tried to reload their fired cases. Those fired case heads were enough out of square to cause problems on the out of square bolt faces.
 

603Country

New member
I shoot my 223 with what you might call light contact or minimum contact when I shoot off the bench, but that's going to be a tough one with a 30-06. Just a couple of days ago I was sighting in my 270 with a new scope, and I was reminded why I really like my 260 so much. The diff in recoil is what you might call noticeable.

And...something that might sound crazy, but years ago I was doing a lot of group shooting with my 220 Swift and a bull barrel (barrel is since replaced with a sporting contour). The rifle was tuned by a top level smith and was a real shooter and under good conditions I was getting some real small groups (5 shot groups that could hide under a dime). Used Norma cases back then and BR primers. But...every now and then I'd get a flyer that I just could not explain. I could see having one just a bit out of where it should be, and that would most likely be due to my mistake. But when I knew I did everything right and still got that shot that was a little too far out to blame on me, I wondered and wondered what might cause that. So I took to marking the case that was associated with the flyer. Next time at the range if I got a flyer with that case again, I tossed the case. Had fewer flyers after that (with those cases).
 

SpringOWeiler

New member
The slow fire technique will give you the best possible results. Taking 1 shot every 30 seconds should eliminate any shooter fatigue. And it allows enough time for the heat build up in the chamber to redistribute itself down the barrel and action and hopefully get rid of those variations as well. I strongly advise this as the biggest bang for the buck testing method when striving for ultimate accuracy. I don't know your rifle or your shooting skills. Maybe its the rifle, maybe it's you. Only through testing will you figure it out.
 

Bart B.

New member
Taking 1 shot every 30 seconds should eliminate any shooter fatigue. And it allows enough time for the heat build up in the chamber to redistribute itself down the barrel and action and hopefully get rid of those variations as well.

It's been my observation and that of many others that shooting commercial factory made centerfire rifles start stringing their shots when shot fast enough that the barrel doesn't cool down to ambient temperature. That's typically caused by the receiver face not being squared up with the barrel's thread and bore axis. As both receiver and barrel expand as they heat up, the high point around the receiver face puts a stress axis on the barrel. It's enough to change the muzzle axis angle to shoot bullets somewhere else than when the barrel was cold.

Once every 30 seconds ususally shows shot impact changing after 4 to 5 shots; sometimes sooner. This has happened with the dozen or more commercial factory rifles I've shot; even a few highly praised 30 caliber match rifles from Remington and Winchester. It's common for commercial factory rifle companies to quote accuracy guarantees for only 3 shots; they know their barrels are fit to non-squared receiver faces and they start to walk shots as they heat up by the 4th one fired.

With the receiver squared up, one can shoot 24 shots in 50 seconds with cartridges like the .308 Win. and .30-06 and shot impact will not change going from ambient to hot enough to cause second degree burns on ones skin. Such is life in some matches where such firing is the norm.
 
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1stmar

New member
Update

Ok good day at the range with your help. Focused on set up and breathing and trigger control. Did some dry fire drills (that was a wake up) and the first group out of the box was all I needed to see. Still some work to do but much more consistent
 

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