Did I do something backwards?

i just glanced threw this but this is probably your poblem.... the scope sits above your barrel by a few inches, wel all know that bore sighting gets u on the paper nothing more.. your bullet will travel on a arc when it leaves the barrel, so the further out it climbs the higher threw the arc it is untill it peaks but then it will start to drop.. but your line of sight is prefectly straight, even the the bullet arcs. so take the bore sighting being off a few inches, the scope center being 2-2.5" higher then ur barrel center and u will be shootin low, get ur windage set and then go out to 100 u will probably be shooting high..



my .338wm will shoot roughly 3" low at 50, 5" high at 100,
 
I took it out to 200 yards after that and had to dial it up a total of 100 clicks from indicated "0" elevation for point of aim and point of impact to come together. The clicks are 1/8. So like 12.5 moa. If I include the 10 moa I theoretically get from the signature inserts that's more that 20 total moa to shoot out to 200 yards.

Something is obviously not right.

ultimate_monkey said:
i just glanced threw this but this is probably your poblem.... the scope sits obover your barrel by a few inches, wel all know that bore sighting gets u on the paper nothing more.. your bullet will travel on a arc when it leaves the barrel, so the further out it climbs the higher threw the arch it is.. so take the bore sighting being off a few inches, the scope center being 2-2.5" higher then ur barrel center and u will be shootin low, get ur windage set and then go out to 100 u will probably be shooting high..

my .338wm will shoot roughly 3" low at 50, 5" high at 100,
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so take the bore sighting being off a few inches, the scope center being 2-2.5" higher then ur barrel center and u will be shootin low, get ur windage set and then go out to 100 u will probably be shooting high
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If the scope is 2" above the bore,and the gun is shooting 5" low at 50 yards,it will be even lower at 100 yards.It is simple geometry.

my .338wm will shoot roughly 3" low at 50, 5" high at 100,
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Unless your scope is mounted more than 3" above the bore,that isn't possible.Again this can be proven with simple geometry.
 
stubblejumper said:
If the scope is 2" above the bore,and the gun is shooting 5" low at 50 yards,it will be even lower at 100 yards.It is simple geometry.



Unless your scope is mounted more than 3" above the bore,that isn't possible.Again this can be proven with simple geometry.
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yup your right, i should really look at numbers, but like i said i glanced threw quickely... my bad

and i said roughly 3" i cant say i shoot my rifle at 50yds so its like i pay super close attention to how it shoots there ;)
 
Installed such that front of scope is pointing down slightly (i.e. thinner insert (-10) on the bottom of front ring, thick (+10) on the top).
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You might think that the scope is pointing down toward the bore,but if the crosshairs are 2" above the bore,and the point of impact is 5" low at 50 yards,even if the scope is parallel to the bore,the bullet would have to be dropping 3" in 50 yards.What cartridge are you shooting?
 
When I first put the rings on I used the 0 moa inserts, front and back, just to see how much clearance I had between the scope and the barrel. I had about 5-6 mm between the front bell and the barrel. I then put on the +/- 10 inserts in the front as previously described and that clearance came down to about 2mm.

I didn't really mean the scope is pointing down, I simply meant that the front of the scope came down in relation to the gun as a way of describing to everyone that I hadn't put the inserts in upside down.

Not sure if I worded that clearly.

stubblejumper said:
You might think that the scope is pointing down toward the bore,but if the crosshairs are 2" above the bore,and the point of impact is 5" low at 50 yards,even if the scope is parallel to the bore,the bullet would have to be dropping 3" in 50 yards.That doesn't make sense,so the scope can't possibly be angled down towards the bore.It must actually be angles upward,away from the bore.
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The crosshairs and bore were obviously diverging with the 0 insets,instead of converging,and they likely still are,just not by as much.Can the rail be reversed?I know that you said that it is marked as a 0 degree base,but it might be marked incorrectly.The only way to tell,is to reverse it.

I just don't want to believe that your load is dropping 3" in 50 yards,but then you haven't provided a cartridge.
 
It does physically allow you to reverse it but it has a cutout on the ejection side so it really only goes the one way. For fun I reversed it and remounted the scope with the same inserts and I have the same clearance (i.e. about 2mm) so I'm pretty sure it's not the base.

stubblejumper said:
The crosshairs and bore were obviously diverging with the 0 insets,instead of converging,and they likely still are,just not by as much.Can the rail be reversed?I know that you said that it is marked as a 0 degree base,but it might be marked incorrectly.The only way to tell,is to reverse it.

I just don't want to believe that your load is dropping 3" in 50 yards,but then you haven't provided a cartridge.
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Do you have a long straight edge to put on the rail to see if the base looks parallel to the barrel?Do you have another scope to try on the rifle?
 
Hope I am hearing you correctly.

Can you steady the rifle in a vise or brace it??

Pull out the bolt and look down the bore.Center the bore on an object then look through and adjust the scope to center roughly on your object.
25, 50 yards away or so.I do this when mounting scopes, very quickly lets you know what is up. keep the scope rings nice and loose so you can move the scope easily.


MHouser said:
Just trying to Jury rig something with to help me optically zero this thing. Any common household items that I could use to do this so I don't have to make something?
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Didn't you already have it adjusted for 200 yards?If so,just assemble it as it was,return to the previous 200 yards settings,and it should be on the paper.
 
Yes it was but as I mentioned I had to dial the scope up a ton to get it on paper at 200. The equivalent of 20+ moa. Now I'm trying to figure out why.

I'm going back to square one to try some of the previous suggestions (i.e. put straight edge on rail and see if rail is parallel to barrel, optically "0" the cross hairs and see if the windage and elevation settings are at or near indicated "0", etc.). Just trying to optically zero the crosshairs at the moment. I normally do that by taking the scope off the gun, putting it in some v shaped blocks and rotate the scope such that the point of aim is pointing at the same spot no matter how it is oriented. Then you look at the dials and if one of them is really far from indicated "0" then there may be an issue with the scope.

stubblejumper said:
Didn't you already have it adjusted for 200 yards?If so,just assemble it as it was,return to the previous 200 yards settings,and it should be on the paper.
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"your bullet will travel on a arc when it leaves the barrel"

Common misconception. No it doesn't, your bullet starts to drop the second it leaves the barrel. By tilting your barrel upwards in relation to the line of sight, you change the arc of that drop, but at no point in time does your bullet climb.

OP - you want to shoot LR with a scope with 50 MOA adjustments? You want your rifle zeroed at the bottom of that 50 MOA. That will give you the entire range (or as much of it as you can arrange) for elevation at long distance. So dial your scope down, bore sight it, then figure out which angled base and combination of rings will get you to "zero at the bottom". If you have a full set of the Burris inserts, you can do it with them too. If you set your scope at zero/centered, then half your adjustments are already used up. That leaves you 25 MOA, and that won't get you to 1000 with a 308. That make sense to you? - dan
 
Ok, with the scope as optically centered as my eyes will permit I got a windage reading of 1moa left and an elevation reading of .6moa up on the turrets so it looks like the scope is fine.

Putting a straight edge on the 0 moa rail and checking it against the barrel it looks like the rail and barrel diverge at a rate of approx. 81 thou per foot (I used the depth gauge on my calipers to estimate this). Quick math. That's (.081 x 3 = .243 / yard) and (.243 x 50 = 12.15" at 50 yards). So a foot low at 50 yards if the scope is zeroed.

It was actually hitting 6 inches or so above that which can be explained by the 10moa signature insert in the front ring helping to bring it up.

I also stuck a level on the barrel and leveled the gun then stuck the level where the rail attaches and they are definitely diverging.

So now what?

Since my rings are limiting me from doing anything more with inserts I guess I'm going to have to swap the high rings for extra high and maybe buy the 20moa insert kit.

P.S. Is it normal for a gun to have this big of a divergence between barrel/bore and mounting area?
 
Is it normal for a gun to have this big of a divergence between barrel/bore and mounting area?
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It's common to have some divergence,but if your numbers are correct,I have never seen that much on any of my own rifles.
 
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