Faulty Leupold or other explanation? Help!

[NWdan]

First off many thanks to this site and it's members for so much valuable information. You've helped me select equipment and set up a rifle that is giving VERY good results (consistant sub MOA) to 1000 yards. I've been shooting my new Remington Sendero SFII .300RUM at 1000 yards and have an issue I can't explain and need some help with. The scope is an older Leupold 6.5 X 20 LRT, 30mm tube, 50mm obective, Night Force 20MOA two piece bases, Warne rings. I'm shooting 200g Accubonds at 3070fps. O.K. so here is the issue, with a dead on center of bullseye 100 yard zero, my groups are averaging 3 MOA right at 1000 yards with no wind. My required come up is 26 MOA (more than JBM calculates by 2 MOA?) and 3 MOA left windage. Today I shot a 5" 3 shot group and #4 opened the group to 10". This is my fifth time shooting this setup at 1K and same results each time - sub MOA groups always requiring left windage. I've noticed in Shawn Carlock's article "Reading the wind" that a right hand twist barrel can cause POI to be right. I'm assuming he didn't mean 30" right. Is it possible that my scope is to blame? When I initially mounted the scope I used the level kit to level the action and placed the second level on top of the elevation turret. After shooting at 1K at impacting right I rechecked the scope level on a building and noticed the reticle was canted left. I loosened up the scope and repositioned it so the reticle is level and plumb with the building. This results in the turret now being out of level with the action. At any rate both scope alignments result in POI to the right at approximately 3 MOA. Any thoughts or help on what could be causing this will be greatly appreciated.

 

[michael A.]

nwdan i have that same scope and it is about 5 years old i just got it back from leupold it had a broken cross hair and wouldnt focus anymore.
have you tryed shooting it at say 300 yards? is it still shooting way right? and are your groups still walking around? if you send it to leupold they are about 3 weeks out. michael

 

[NWdan]

michael A., I shot last weekend at 500 and didn't see any POI shift to the right. It is wierd. I guess what I should do is shoot 600 -700- to 1K to see if it gets progressively worse as range increases. I always hate the hassels of sending a scope in but I'm not sure what else could be causing this. I would think the elevation turret should be square with the reticle but maybe that is not important. I'm not sure??

 

[tjonh2001]

thats why i like etched reticals no worry of broken reticles. but to the question at hand you need to be conserned about that scope. you should level the retical even if the turrit is canted off to one side. you can send the scope in to the leupold custom shop and they will realine the retical and turrit for you . at the same time they will check out your scope and make sure its in good working order.

 

[NWdan]

tjonh2001, I think you are right about sending the scope in. Is it possible that the scope is actually tracking right as I run the 26 MOA up elevation? At one point I did shoot one shot in the bullseye at 100 yards, then keeping the target at 100 yards ran up 26 MOA an shot again. That shot was in perfect verticle alignment. I would think if the scope is moving right wth up elevation it would show up at 100yards wouldn't it?

 

[goodgrouper]

First off many thanks to this site and it's members for so much valuable information. You've helped me select equipment and set up a rifle that is giving VERY good results (consistant sub MOA) to 1000 yards. I've been shooting my new Remington Sendero SFII .300RUM at 1000 yards and have an issue I can't explain and need some help with. The scope is an older Leupold 6.5 X 20 LRT, 30mm tube, 50mm obective, Night Force 20MOA two piece bases, Warne rings. I'm shooting 200g Accubonds at 3070fps. O.K. so here is the issue, with a dead on center of bullseye 100 yard zero, my groups are averaging 3 MOA right at 1000 yards with no wind. My required come up is 26 MOA (more than JBM calculates by 2 MOA?) and 3 MOA left windage. Today I shot a 5" 3 shot group and #4 opened the group to 10". This is my fifth time shooting this setup at 1K and same results each time - sub MOA groups always requiring left windage. I've noticed in Shawn Carlock's article "Reading the wind" that a right hand twist barrel can cause POI to be right. I'm assuming he didn't mean 30" right. Is it possible that my scope is to blame? When I initially mounted the scope I used the level kit to level the action and placed the second level on top of the elevation turret. After shooting at 1K at impacting right I rechecked the scope level on a building and noticed the reticle was canted left. I loosened up the scope and repositioned it so the reticle is level and plumb with the building. This results in the turret now being out of level with the action. At any rate both scope alignments result in POI to the right at approximately 3 MOA. Any thoughts or help on what could be causing this will be greatly appreciated.

I see two possibilities here. Gyroscopic drift will impact bullets to the right but shouldn't be over 30". But it could be possible. Some guns exhibit bad drift and othes don't show any at all.

The other possibility is canting of the rifle. The only really good way to mount a scope is to level on the lug raceways with a reticle leveling window tool. The level a target board and parallel the horizontal crosshair with the top of the board to double check.

Putting a level on the top of the turret sounds like a good idea, but they are not always parallel with the horizontal crosshair.

Check these two things and if it still has a problem then send it back to Leupold. You will have it back in under two weeks.

 

[michael A.]

nwdan when did you start having trouble at 1k if it was after you shot at 500 i would try shooting it at 500 again and see what it groups like now
im not sure about the turret one would think it sould be square.
michael

 

[dmgreene]

NWdan send the scope back to Leupold. I had the same problem with a canted reticle in a VXlll. The reticle and the turrent should be parrallel with each other. With my POI dead on at 100 yards I would be about about 18" to the right at 700 yards. I have read about others having the same problem with Leupolds.

 

[royinidaho]

You'll get about as many ideas here as you will get responders......

I'd go with what GG said but.......first I'd try this:

Make a plumb bob. Mine is a very long piece of string (celing to floor length) , a partial neck sized case (your 300 RUM would be perfect) and a bullet.

That is, if you don't have a plumb bob readily available.

Stick the string through the flash hole and out the mouth a ways. Tie a large knot in it so it won't pull back through the flash hole. Pull the knot to the back to the case head and set a bullet in a little ways.

Find the longest open span in the house. Like from the bathroom down the hall and into the garage, or what ever. Hang the plumb bob from ceiling to floor. While it stops swinging set up a table at the other end of the open area.

Mount the rifle on the table level. Use a cleaning vise and a bubble out of a cheapie lever for on top of any flat spot on the action. Top of rear mount, magazine rails etc.

level the rifle precisely, if that is possible with a bubble level.

Then center the cross hair on the plumb bob string. Reverifying level constantly.

Then turn the scope until things are parallel. You'll know then what you have.

Additionally once setup solid and lever. crank up the elevation and see if the + reticle goes straight up.

GG's method is way more nifty but this way is way more fun. Plus anyone else in the house get to gen up some interesting comments.

But hey, it works.....

 

[NWdan]

Thanks all for the advice on leveling the scope. I do have a level that sits on the action rails. Using that and lining up on a building that is level / plumb I set the crosshairs so they should be exactly square with the action. After my initial outings and shooting right I bought a Sinclair anti-cant level that arrived this week. I mounted it up and used it this weekend with my buddy watching me shoot to make sure I wasn't canting. Shots broke with the level right in the middle and still hitting 3MOA right at 1K. I hadn't thought to run the scope up on the plumb bob with everything locked down, I'll give that a try to check verticle.

Part or all of the problem could be the Gyroscopic drift that GG mentioned as well. Having never shot this far I wasn't aware that was possible. I guess as long as it is the same every time I can correct for it.

dmgreene, was your promblem corrected when you got your scope back and started shooting again? On mine I just don't understand what would be wrong with the scope when it shot into a verticle line with 26 MOA up elevation at a 100 yard bullseye.

 

[Jon A]

Unfortunately it sounds to me like a canted reticle. This is one of the things I like to check for with a boresighter/colimator (the Leupold is quick and easy to use).

Line the reticle up with the grid and crank your turret. The intersection of the reticle should stay on the same line all the way down. If it doesn't, it's not square with the turrets and that will cause serious problems as you've found out.

Hopefully Leupold will fix it for you.

 

[Mikecr]

Just level the turret. A square elevation adjustment will impact true, regardless of reticle cant.

 

[dmgreene]

dmgreene, was your promblem corrected when you got your scope back and started shooting again? On mine I just don't understand what would be wrong with the scope when it shot into a verticle line with 26 MOA up elevation at a 100 yard bullseye.[/QUOTE

NWdan they did fix my scope. However my gun would start shooting to the right at 100 yards as I started dialing in more MOA. Remember that it would only take 3" off the verticle line to be off 30" at 1000 yards.
David

 

[Jon A]

Just level the turret. A square elevation adjustment will impact true, regardless of reticle cant.

Bah. Life is too short to shoot with a crooked reticle. Just my opinion.