scope is out of up elevation. time to shim?

Morpheus32 said:
Check to make sure your mount/base is the correct one for the receiver you have. I had a similar problem and in the end, it was the base that was at issue. Cost $20 to get the right one and that was it. I would go with the easy solution first before you start shimming/devcon or mucking about. The cheaper the base, the more likelihood of issues as well.
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:agree: Avoid shimming & check the base.
 
Link said:
Shim the back for every .001 you add on back base will give 1 inch at 100 yards
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That is only correct if the barrel is about 3.5" long.

Here is a breakdown on the math. For Example a Garand Sight radius is approx 27.9". To get a 1" change at 100 yards (approx 1.047 MOA) the sight changes about 0.008"

Inverse Tan 0.008/27.9 = 0.01745 degrees x 60 = 1.047 MOA (an inch @ 100 yards)

For a scoped rifle you are concerned about the angle you are raising the bore. Use the centre of the scope optic to the muzzle.

For a shim height or iron sight change calculating backwards take the

Tan (Hx1.047xB/60)

H =Height in inches at 100 yards change desired.
B =Sight radius or for scope centre of optic to muzzle in inches.

Example for that garand 1 inch change at 100 yards is

Tan (1x1.047X27.9/60) = 0.008497"

I only read the first page of the posts and never saw any particulars on your rifle or scope you are using. How far out at 100 yards are you.

For a recommend I love the 1 piece picitinny rails with the 20 moa slope and use then on most of my rifles. It even allows me to take the 22LR to 400 yards without holdover. Youtube Video ( http://www.youtube.com/watch?v=rHI4C9BIdj8 )

Evolution Gun works ( http://egw-guns.com/store/index.php?main_page=index&cPath=39&zenid=c0e086c2d925bdf74b460057133af06c )are reasonable and ship here no problem. I have one on my Savage 12 VLP DBM .223, Savage BTVS Mark II 22LR. Browning A-bolt 300 win mag and now my dads Browning BLR .308. This allows 1 scope to do multiple duty between all guns with awesome return to zero on each.

Most scopes have about 50 MOA vertical in them. (My Bushnell 6500 2.5-16 has 90MOA) Optically centered that 25 moa up elevation left. I have found most actions mounts are parallel to the bore or close. For you to not be hitting at 100 yards with max travel on the scope is a lot of error. Is the scope even tracking at all.

Hey maybe you got all this fixed on page 2 or page 3 but I had to jump in and correct the error of the math from that Quote.

Cheers
 
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First option I personally would opt for (and have) is a 20 or 25MOA base.

Next best thing - being as I think something is wrong with the rings, or the bases, meaning there's likely mean scope tube stress happening too - would be Burris Signature Zee rings with the shim kit for those. Give it a .020 lift in the back, and a .010 drop at the nose, let the ball joint magic of the inserts also take out any whacked out scope tube stress at the same time.

Jerry aka MysticPlayer on the forums here is my personal favorite source for any of the above mentioned items.

Cutting pop-cans etc to make shims is far too bubba....going to wreck something doing that.
 
Dogleg said:
You mean a salvage with a trashco right?:nest:
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I'd assume remington SPS and the splendid machining jobs those have been showing up with lately...I saw a farrel base (two - assumed one was garbage)being a "stoutly" machined one peice base that SHOULD fit the action snugly front to back of action - torqued down at the front hovering 1/8" above the rear of the action. Top quality fabrication on the low end remmies these days. I think I still have pictures of that momentous occasion somewhere :D
 
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That is only correct if the barrel is about 3.5" long.
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The barrel length doesn't matter, the distance between the rings and the amount of shim does. Draw yourself a picture and apply your math skills to the correct triangle. The barrel length doesn't matter any more than the length of the scope does.
 
xring_assassin said:
I'd assume remington SPS and the splendid machining jobs those have been showing up with lately...I saw a farrel base (two - assumed one was garbage)being a "stoutly" machined one peice base that SHOULD fit the action snugly front to back of action - torqued down at the front hovering 1/8" above the rear of the action. Top quality fabrication on the low end remmies these days. I think I still have pictures of that momentous occasion somewhere :D
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You know, even without getting into brand names, I agree with you on the action machineing. That's why I've already taken the position that changeing good bases on a bad action isn't a cure or even a solution. At that point, shimming or bedding the base to compensate is about the only move left. You can put a 20 MOA rail that doesn't fit on, bend everything with the mounting screws and get the gun sighted but thats not addressing the real problem.
 
Dogleg said:
You know, even without getting into brand names, I agree with you on the action machineing. That's why I've already taken the position that changeing good bases on a bad action isn't a cure or even a solution. At that point, shimming or bedding the base to compensate is about the only move left. You can put a 20 MOA rail that doesn't fit on, bend everything with the mounting screws and get the gun sighted but thats not addressing the real problem.
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I agree 100% - if your scope is out of elevation - my NEW reccomendation is "TAKE IT TO COMPETENT GUNSMITH and get them to look at it".
 
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