Problems truing scopes for long distance shooting

[stagpanther]

What I normally do: after scope is set on the rifle with rings loose around the scope. Clamp the rifle in a bench vise, put a bubble level on the rifle rail and level rifle, clamp the rifle down so it's very snug, 6 to 15 feet away on a wall hang a plumb bob or use a good level and draw a line on the wall, dim the lighting and shine a bright flashlight thru the scope from the objective end, this will cast your cross hairs onto the wall with the line or plumb bob, adjust your cross hairs accordingly, as you tighten the scope rings watch carefully that the rifle bubble level and scope cross hairs do not move. The above is assuming you have your eye relief for the scope set and other obvious things completed.
This should help eliminate your wind problem and prizm issue looking through glass. I hope this helps. I always do the tall target test after this to confirm scope and bore are true.

Thanks for that--and welcome to the forum. Pretty much what I did using the technique linestretcher recommended--though I have yet to do the tall target test to see how true tracking is. Conditions are pretty tough here at the moment--all the snow and ice is starting to melt and it's making a giant mess.

[RaySendero]

Good thread!

I have a friend who uses the same GS to bore scope all his rifle scopes.
Every time when we go to sight-in,
his scope cross hairs are canted and do not bisect to bore.
So I've now got some ideas to share with him.
1st of which will be to try a different GS.

[LineStretcher]

There's a lot of things that can go wrong when mounting a scope. There are several things that need to be checked during the process. The first thing I do is to find the level point of the action. Sometimes I have to remove the stock to keep it from interfering with the level point.

I use the Wheeler leveling kit so that once I find and verify the level point I can transfer that to the barrel and then check my mounts or rail to make sure they are level and true to the receiver. You would be surprised how often they are not and need bedding to correct them.

Once I know that my rings are as true to the bore as I can get them, I lap them to make sure the scope fully seats into the rings and that there is no binding. Some people don't agree with lapping rings but I think that's more that they don't want to buy the lapping tools rather than understanding why it's done.
Once I'm done with all that I mount the scope, adjust for correct eye relief and torque the mounts to the recommended specs. Typically that's 15 to 17 inch lbs. I then loosen the screws equally and hang my plumb line with a black dot on the wall that I'll use to align the barrel with. I either use a laser bore sight or remove the bolt and look through the barrel and align the center of the bore with the black dot. I use the barrel mounted level to ensure that my rifle is level and then I turn the scope so that the cross hairs are aligned with the plumb line. I often adjust the scope windage at this time also since it is easier to see small differences.

Once everything is lined up through the center of the rifle bore I snug the rings equally and re-check. If everything is good then I torque to specs and consider it ready to go to the range for an initial 25 yard sight in.

Many will disagree with the need to be this anal about mounting a scope and that's fine. I do it because it make me feel warm and fuzzy I guess.

[stagpanther]

Good thread!

I have a friend who uses the same GS to bore scope all his rifle scopes.
Every time when we go to sight-in,
his scope cross hairs are canted and do not bisect to bore.
So I've now got some ideas to share with him.
1st of which will be to try a different GS.

The vast majority of GS's are set up to get their main product out the door--which usually means a minute-of-deer rifle with a 3 x 9 duplex scope. I wouldn't leave anything demanding precision to a GS--unless that is what they are known for; and you are willing to pay for it.

I've been trying out Berger match-grade vld's lately--my pet theory is that Berger makes them to exclusively work well in only Bryan Litz's rifles' bores (just kidding in case you read this )--but the typical ladder stuff isn't bringing joy--and I realize that jump to lands is the most important variable when developing loads with the vld's. So what I'm going to do is develop charge ladder--looking only for the best SD's; and then do the Berger jump-to-lands ladder to see what--if any--brings happiness to my rifle.

[Rob228]

I could be mistaken, but I would say your dining room table and your floor are the weak points in the equation of your method.

[stagpanther]

I could be mistaken, but I would say your dining room table and your floor are the weak points in the equation of your method.

That definitely occurred to me--I started by removing the rings and scope and using a carpenter's level leveled the receiver (a good check that linestretcher mentioned--going the extra mile to bed his rail-- I did not do). I think building a "true station" with a rigid vice hold is in my future--just torquing screws tended to throw things out of true--especially the bubble levels. The bubble levels I bought pretty much suck--under recoil from my heavier recoiling rifles they do strange things like "split bubble mitosis."

[bamaranger]

Leveling a scope is a troublesome task for me too. And much of what S-panther describes has appeared in my troubles. Looks good in the den, at the range, the dang thing is canted, usually right. I've gotten to the point that I do not snug a new rig up till I have it outdoors. I also will pass the rifle to another pal or shooter and ask if the scope seems square. Eventually it gets to where I'm satisfied.

Plumb line, bubble level on the rails, done all that, seldom does it all line up for me and what I see through the scope. It has been suggested I have some type of vision problem. I also may mount the rifle a tad canted shot to shot.

Just recently I put a scope on a rifle for bamaboy. We took it to the range....he sets down behind the gun, takes one look......"I can tell you mounted this scope" . I look through it.......canted left. I SWEAR that dang thing was square the night before in the den. Luckily we had tools, and loosened everything up and got it right. Tracks well vertically too I'll add.

But it was the usual hassle......I hate the task.

[stagpanther]

I'm beginning to realize that there might be other factors can creep into the setting true process which may or may not be a factor (I could be off my rocker too in my speculations, just food for thought):

1. As much as I appreciate the close-up through the objective technique; it requires taking the magnification and parallax settings down to the "minimal use" end which may not necessarily track as reliably or accurately as the scope's more "likely" range of settings, even the cut of the lens may possibly come into play (?).

2. It's not uncommon for me to have the POI for a group to shift simply as a result of a change of hold technique--for example changing from bags on a bench to prone with a bipod. I tend to "hover from above" when leveling and making the changes--only periodically looking through the scope to check the true during the setting process--it occurs to me that in the truing process you might need to "simulate" your intended actual shooting position as closely as possible, cheek weld, trigger hold etc (?).

[HiBC]

Then there are the evil people who make this an inside joke. Every new scope or rifle will get the comment "Scope is crooked" just to drive you crazy.

There comes a point where there is not a bolt on fix.

If you are shooting at "long range" you are going to make W+E adjustments.

You can rely on a spirit level to keep your cross hairs oriented.

May I ask,do some very good shots use a dot reticle?

Its helpful if the W+E tracking are plumb with gravity. But if you stack your bones steady and that gives you 6 degrees cant at natural point of aim with your ears level,say,standing,and you are level,zero cant,at prone...your notes are going to tell you "X" number of clicks windage at 600 yds when shooting standing.

[stagpanther]

Yes--I understand that and I'm sorry if I'm sounding like I'm trying to blame the gear, I'm not really. It's really just my way of trying to learn. : ) I've never been interested in trying a comp but may give it a go once I think I have a better grasp of what I'm doing. Thanks to everyone for your helpful suggestions.

[LineStretcher]

2. It's not uncommon for me to have the POI for a group to shift simply as a result of a change of hold technique--for example changing from bags on a bench to prone with a bipod. I tend to "hover from above" when leveling and making the changes--only periodically looking through the scope to check the true during the setting process--it occurs to me that in the truing process you might need to "simulate" your intended actual shooting position as closely as possible, cheek weld, trigger hold etc (?).

Let me help you with this.. Its not you and it's not uncommon. When we build precision rifles we do everything we can to remove all the factors that can change the normal harmonics of a rifle barrel when it's shot. If your rifle is off the shelf and you haven't done anything to improve it, then changing from bags to a tripod can change the harmonics and will affect your groups. Bags should give you the best grouping because it is the closest to off hand shooting which is what the rifle was designed to do.

My suggestion is to first check the bottom screws in your rifle. To do this, loosen them fist. Next, tap the rifle butt on the floor a couple of times and then while still holding it vertically, tighten the rear screw to 35 inch lbs and then the front to 35 inch lbs. If your stock has aluminum pillar posts you should torque to 65 inch lbs. Make sure you have pillar posts if you go to 65 because you can damage your stock if you don't.

Next, remove your bipod and shoot off of bags. That will let you know how the rifle really shoots and you can start trying different ammo to make it better.

[stagpanther]

Let me help you with this.. Its not you and it's not uncommon. When we build precision rifles we do everything we can to remove all the factors that can change the normal harmonics of a rifle barrel when it's shot. If your rifle is off the shelf and you haven't done anything to improve it, then changing from bags to a tripod can change the harmonics and will affect your groups. Bags should give you the best grouping because it is the closest to off hand shooting which is what the rifle was designed to do.

My suggestion is to first check the bottom screws in your rifle. To do this, loosen them fist. Next, tap the rifle butt on the floor a couple of times and then while still holding it vertically, tighten the rear screw to 35 inch lbs and then the front to 35 inch lbs. If your stock has aluminum pillar posts you should torque to 65 inch lbs. Make sure you have pillar posts if you go to 65 because you can damage your stock if you don't.

Next, remove your bipod and shoot off of bags. That will let you know how the rifle really shoots and you can start trying different ammo to make it better.

Good suggestions--the other day when I started "spraying" with my 338 lapua I discovered the rail was actually loose on the receiver--and did a check of the action screws after encountering the rail problem.

[stagpanther]

Sorry guys--I spaced out--I'm running another thread about bags vs bipods and that's really where the above post should be.

[stagpanther]

OK--you guys may laugh at this; but what I discovered eventually was that for all the truing I do--my bipod, which is apparently adjustable for cant, was simply shifting under recoil. Umm yes, I didn't think of something that obvious.

Yesterday I went out to shoot my 338 Lapua and finally gave upon the cheap bubble levels I bought--(actually $25 a pop isn't so cheap, but relative to accuracy at long range the take-away lesson for me it's worth it to spend the extra money on a good set-up). The lower level on my rail simply blew out from the housing, and the level my scope continues the annoying habit of the bubble reproducing itself into smaller bubbles. I suppose I deserve it since I violated my own golden rule of "never buy Chinese-made optics."

I'm currently interested in the "send-it" digital level--any comments/experience with one?