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Old November 4, 2018, 02:49 PM   #1
Chaparral
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Rifles that don't bore sight well

I've been shooting a long time like most of us in here. Every once in a while we come across that rifle that we slip the bolt out of, get it lined up at an object and then tweek our scope to line up. We fire the rifle and we have no idea where that round went. But we have done this simple sighting technique with many other rifles with success. Hec many times I can remember being near bullseye at 100 yds after bore sighting a rifle. But as I said every once in awhile bore sighting is way off. I wonder what makes some rifles do this?
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Old November 4, 2018, 03:13 PM   #2
Mobuck
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bent barrel
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Old November 4, 2018, 05:11 PM   #3
Chaparral
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bent barrel
Well I kinda feel stupid. It doesn't happen often, but when it has I wondered if the barrel could be misaligned, scope base holes off center, or as you say barrel bent. Strangely the times I remember it happening it was on expensive, new rifles. One I traded off after many days scratching my head at the range, and the other one I still have and it shoots great groups once I figured out where the bullet was going.
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Old November 4, 2018, 05:25 PM   #4
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This one for sure:
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Old November 4, 2018, 06:38 PM   #5
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Two issues

1. Bent barrel as noted

2. Light rifle that has a lot of recoil (270/280/308/30-06) with significant recoil that the variation in where the bullet release is affected by the hold.
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Old November 4, 2018, 07:33 PM   #6
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If the barrel was bent I'd think you'd see it when bore sighting. If the the bull is centered in the bore, and the cross hairs are in the same spot, the bullets will impact within a couple of inches.

If there were problems with the scope, mounts, or holes in the receiver you could still get the rifle zeroed unless you ran out of adjustment. That is why they make windage adjustable mounts.

I'm going with you just have a bad day once in a while.

I bore sight at 50. Most of the time the 1st shot is almost dead on, but occasionally may be 5-6" from where I'm aiming. Which doesn't matter, as long as I hit paper I can figure out how much to adjust the scope and how far.
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Old November 4, 2018, 07:53 PM   #7
Chaparral
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If the barrel was bent I'd think you'd see it when bore sighting. If the the bull is centered in the bore, and the cross hairs are in the same spot, the bullets will impact within a couple of inches.

If there were problems with the scope, mounts, or holes in the receiver you could still get the rifle zeroed unless you ran out of adjustment. That is why they make windage adjustable mounts.

I'm going with you just have a bad day once in a while.

I bore sight at 50. Most of the time the 1st shot is almost dead on, but occasionally may be 5-6" from where I'm aiming. Which doesn't matter, as long as I hit paper I can figure out how much to adjust the scope and how far.
Yeah I bore sight identically to your method. I bore sight at 50 then fire at 100. I wish I could blame it on just having a bad day. I finally resorted to buying the Burris rings with adjustable plastic shims. Finally I just had enough one day thinking that I shouldn't have to do all of this just to make an $1800+ rifle shoot correctly.
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Old November 5, 2018, 06:22 AM   #8
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I bore sight at about 50 feet in my cellar, using a "target" that came with the bore sighting laser, but shooting on the range, first target at about 25 yards usually produces a hole in the target, which I adjust on, then shoot at 100 and always hit paper.

Semi-autos, levers and pumps are sometimes bore-sighted using a small mirror in the breech. Bore sighting laser tools work okay, but are not perfect and shouldn't be relied-on for final sighting. (Some stores will try to tell you that their bore-sighter works perfectly and that the rifle is ready to hunt with. That's a bunch of malarky, unless you happen to be hunting barns.)

Last edited by Picher; November 8, 2018 at 09:08 AM.
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Old November 5, 2018, 07:39 PM   #9
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I bore sight at 100, some guns its spot on and others not.

Its consistent with which guns are on and which are not.

Conversely, get your gun on at 100 and then bore site it.

It can be quite a wake up.
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Old November 5, 2018, 10:13 PM   #10
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There are a number of factors that can affect things, the thing being affected is the bullet's flight, compared to the line of the bore.

A bore not centered in the barrel, a bent barrel, an uneven muzzle crown, bedding, forearm pressure on the barrel, barrel whip, and other things, any one of which can case a deviation in bullet flight from the line of the bore.
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Old November 6, 2018, 01:07 PM   #11
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"...what makes some rifles do this?..." All rifles will do that if the thing wasn't securely held in place when you were bore sighting by looking through the barrel. That method works but not as well as using a proper bore sighter. Doesn't work well with small calibres either.
Bore sighting only gets you on target. It's not sighting in. It's good for getting the vertical reticle absolutely vertical too.
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Old November 7, 2018, 12:25 PM   #12
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Quote:
Originally Posted by T. O'Heir
Doesn't work well with small calibres either.
I always thought it worked better with smaller calibers... the area you can see is smaller (like trying to aim a laser instead of a flash-light) and being off-center is more obvious, almost like scope shadow.
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Old November 7, 2018, 04:17 PM   #13
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Best to bore sight at closer range , then it should be on paper at 50 yards so you can sight in. Never heard of bore sighting at 100 yards.
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Old November 7, 2018, 04:46 PM   #14
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Never heard of bore sighting at 100 yards.
Do it with the rifle clamped in a cleaning vise. With the bolt out, bump the vise and/or shim it until you can look down the barrel to see a target in the center of the bore then without moving the rifle adjust the crosshairs to match what you see through the bore. Something large and round that stands out works well for this - like a basketball.
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Old November 7, 2018, 08:47 PM   #15
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Bore sighting a Rem .17 would be a pain. Especially with my eyes!
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Old November 7, 2018, 10:35 PM   #16
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ever think it might be a scope issue at times ? Even good scopes can get wonky. I had a Leupold vx III that absolutely refused to work on one of my rifles. The windage needed to be almost all the way to the right. I unmounted and mounted that scope three times convinced it was something wonky about it sitting on the rail cockeyed. never could get it to center. Swapped it out with a scope on another rifle and everything is working as intended on both rifles to this day
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Old November 8, 2018, 09:22 AM   #17
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Sometimes it's not the scope, but the way the action and/or barrel is bedded. I've seen barrels bearing on one side of the channel, probably due to stock warping and that caused bullets to hit several inches away from where they're bore-sighted. That's one reason I recommend free-floating barrels because wood isn't static, and often changes during the hunting season, especially if taken out in the rain.
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Old November 8, 2018, 09:55 AM   #18
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Originally Posted by Chaparral View Post
I've been shooting a long time like most of us in here. Every once in a while we come across that rifle that we slip the bolt out of, get it lined up at an object and then tweek our scope to line up. We fire the rifle and we have no idea where that round went. But we have done this simple sighting technique with many other rifles with success. Hec many times I can remember being near bullseye at 100 yds after bore sighting a rifle. But as I said every once in awhile bore sighting is way off. I wonder what makes some rifles do this?
Usually, I find the problem in the scope bases. I've gotten so that I now check my bases for level across the action both front and rear. I rarely find them to be exactly the same so what I do is try to adjust them to split the difference which lessens the amount of torque on the scope tube. If I can't adjust them then I bed them in JB Weld using the recoil lug of the barrel as my reference to level. Sometimes the recoil lugs are out of whack too but that's not very common.
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Old November 8, 2018, 10:00 AM   #19
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Never had that happen. Probably bore-sighted 200 rifles at 25ish yards and all were within an inch or two at 100. Small bores, large bores, bolt guns, ARs.
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Old November 8, 2018, 12:32 PM   #20
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Never had that happen. Probably bore-sighted 200 rifles at 25ish yards and all were within an inch or two at 100. Small bores, large bores, bolt guns, ARs.
I don't own an AR, but just out of curosity, how does one bore sight one of those without a light or laser?
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Old November 8, 2018, 12:58 PM   #21
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I don't own an AR, but just out of curosity, how does one bore sight one of those without a light or laser?
I pull the upper, remove BCG, clamp in vice (handguard with rubber jaw inserts), boresight like you would a Bolt gun.
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Old November 8, 2018, 04:42 PM   #22
Don Fischer
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The older I get, the more off I am. It's probably not the barrel or scope ect. It's you! Your eye's are not that precision. As a younger man, before glass's I could do pretty well but still every now and then I'd mess it up. Little trick to try. Bore sight at 25yds and got from there. A bullet right on horizontal and about an inch low will put you on target at 100yds!
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Old November 8, 2018, 07:32 PM   #23
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I usually put the rifle in my cleaning stand and lately, bore sight on a 2" orange dot I put on on a big tree across a field about 100 yards away.

Then I take it to the range and shoot at 25. Im usually pretty close to POA with the first round. Adjust it on there, and then shoot at 100, and zero to either an appropriate BSZ/PBR for the round at 100.

5 to 10 rounds total is usually all it takes.
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Old November 8, 2018, 07:36 PM   #24
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Best to bore sight at closer range , then it should be on paper at 50 yards so you can sight in. Never heard of bore sighting at 100 yards.
You heard it here first!

There are two aspects, closer in means it does not matter as much, further out and you increase the accuracy but in the case of a non happy result, you loose a 5 shot group (if its on close enough I shoot all 5 then adjust)

So it at 25 or 50 and then you have to make major adjustment as the movement take a lot more dial. the 1/4 or 1/8 movement has to be doubled.

Key is you focus on a smaller spot at 100 (target, the orange clay pigeons are good, pieces of them etc)

It just take some out of the box thinking.
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Old November 8, 2018, 07:58 PM   #25
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Actually, the farther away your target is the better you should be sighted. I try to use something small but obvious... like a lone maple leaf, or an actual target with a bullseye. I often use something that’s 100 yards away.... I’ve been known to use something very large and very far away.... like a truck that just happens to be there or an entire tree or house... or the side of a mountain.... might be 1/2 mile, or 10 miles away... always hit paper at 100.
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