Scope Canting

[Tall]

I know this is a subject that has been discussed before and I have gotten some sugestions. My problem is that my 7mm remington mag is spot on at 200 yards but at 600, 800, & 1,000 yards I had to hold left on the target to make a hit. I felt like what wind there was was a 6 o'clock wind and should not have made a difference in my shot. I have not yet checked the method were I shoot a series of shots at 100 yards moving my elevation turret up 5 to 10 MOA each time to track if the bullet is going off horizontal.

My question is this. I do not have a scope level on my Night force 5.5x22. If i was slightly canted could it make that much difference. I am not sure if I just need more experience reading the wind or what my issue is.

I am going to go out in a few days and shoot the 100 yrds changing the MOA's to see what my results are.

 

[Tall]

It seems like at the 1,000 yard mark I was holding on the very left side of the target to hit the center. The target was very large metal plate. I think it is a 4 or 5 ft metal target.

 

[Michael Eichele]

6 degrees of cant is barely detectable but can cause left or right missed of 4-6' at 1k. 6 degrees is the 1 minute hand on a clock. Not much.

Right hand hits at long range with a level scope/receiver is caused by spin drift and the coriolis effect.

 

[porkchop401]

Spin drift ! is the most likely culprit . I add 1/2 min to the windage at 1000 yds with my 338 but consult a a balistic calc to figure yours . A scope canted to the left will counter the spin drift with a right hand drift . A right hand cant will exagerate it. The funny thing is with the right amount of cant you could have virtually no spin drift!
A scope level properly installed is indeed a good addition to any long range rig.

 

[Joe King]

300gr 338 Berger MV of 2830 with a 1in10 twist has a spin+Coriolis drift of 1.4in at 1k, your canting your rifle (assuming 0 value wind), a scope level will go a long ways for you, I do the same thing myself.

 

[blkdog]

I recently added a scope level to my new Cooper. When at the range , I was very surprised to notice how many times I was canting the rifle to make small adjustments in the location of my crosshairs. I am now a believer and will soon have levels on more of my rifles. Midway has one on sale made by Wheeler that is inexpensive and folds back. It could be an issue if you forget to fold it back when not in use but I am trying one for a while to see.

 

[Tall]

I know i am never going to win a Long Distance shooting contest with this gun at 1000 yrds. I just want to be able to produce reliable first round critical hits on an animal. My concern is that if I was holding 2 feet to the left and putting a 5 inch group in the middle of the target, even if there was a 9 o'clock 5 mph wind my chart says 7.83 inches or .75 MOA. If I was canting and there was a wind witch to me it seemed I had a 6 to 7 o'clock wind that was mild to no wind, maybe 3 MPH at best.

I am buying a scope level today but I can't go shoot again until Monday. I plan to double check the gun level and scope level just to see if there is an issue there. I also plan to shoot a target adjusting the MOA's up in 5 MOA increments. My hold over at 1000 yards is 20.49 MOA.

One thing I have learned there is always a variable that is making an effect. Its just a matter of ruling every possibility out until you find the solution. Just trying to start out with the most obvious ones first.

 

[Joe King]

sounds like your headed in the right direction.

 

[porkchop401]

Installing the level plum is tedious but necessary. Here is how I to do that 1st. square the scope sighs rail 2nd place the level on loosely 3rd draw a vertical line at least 3 ' long with a carpenters level on a target a hundred. Yards away. 4th hold the rifle so that the vertical hair lays on top of the drawn line from top bottom 5th tighten thelevel in place.

 

[Alan Griffith]

Twice in the past few months I've watch shooters I was instructing cant their rifle and miss by 12" at 660 yds and 4' - 8' at 1000 yds. I kept watching through my spotter at first. It wasn't until I came off my spotter and actually watched the shooter that I noticed the cant in their rifle. It happens. Install a level bubble and check it just before each shot. It is especially useful when shooting in hilly or mountainous terrain.

Alan

 

[azsugarbear]

Before you install your level, you should double check your rifle & scope alignment. The quickest way to do this is to use a weighted plumb line on your target. Mark high & low on the string and then draw your perpendicular line on the target. I use a square for this.

Level your rifle in a gun rest/vise (preferable) or on bags, using your level set on the rail. Once this is done, install the scope in the rings and rotate it until the perpendicular cross hair lines up perfectly with the vertical line drawn on the target. Make sue rifle and scope are perfectly lined up and then tighten. Once this is done, use your perpendicular cross hair on your vertical line as a guide and then mount your level. This will get most, if not all of the cant removed from the rifle & scope without firing a shot.

You can double check your work by firing at the line using multiple dial ups as you go.

 

[Tall]

I am thinking the easiest and fastest way to set this up at the gun range is, Use a large target with both horizontal and vertical lines. Then attach a plum bob to perfectly align the target at 100 yards. I use a caldwell led sled, I think I can secure my gun in that and get it level. I may use a tie down strap to hold it secure while i check level on the gun. I hope that I wont even need to move the scope because I already did this process at home. I used a plum bob at 20 yards. Everything looked good. I wouldn't think there would be a difference at 20 yards or 100 yards. I still plan to double check it anyway.

 

[drbill]

I like to put a piece of clear scotch tape on the rings and the scope. Then mark the two pieces of tape with a pencil so you have a reference.

 

[azsugarbear]

Tall, Sounds to me like are ready to git 'er done.