Rifle Scopes Reason for near-maxed out scope travel 0moa base?

[Tomekeuro85]

I still don't know whats going on...

I dont have much experience with scopes, but here is the situation:

My friend, on his 700 with no base, just rings directly on the action, has my bushnell elite 4200.

I have the same exact scope on my 700, just lower rings.

Both are .223.

My scope is zero at 100, and still has 100clicks of 1/8moa each till it maxes out at the top.

His scope is zero 100, and has only 15 clicks of 1/8moa before it tops out. they both have the same overall travel range plus or minus a few clicks.


The only thing I can think of is that his rings are not straight?

 

[deadly0311]

Re: Reason for near-maxed out scope travel 0moa base?

is he sure that his rings dont have a cant built in? If so, did he make sure that the higher ring is in the back and not the front?

 

[Pflyinguy]

Re: Reason for near-maxed out scope travel 0moa base?

Confirming it's the up travel that is affected? I ran into the same problem with a 0 moa Leupold base and Leupold High rings with a Millett scope. I had 15 clicks of up travel and well over 100 (too many to count) of down travel. I'm ordering a 30 moa base to offset the difference.

 

[Tomekeuro85]

Re: Reason for near-maxed out scope travel 0moa base?

Yea its the up travel.... It zeros at 100yds, but the point of impact won't go up more than a few more inches and it stops there... maxed out at the top of its travel, it hits a few feet low at 300.


I dont think the rings are canted but I can double check.

 

[Jerry R]

Re: Reason for near-maxed out scope travel 0moa base?

Another factor which could affect vertical travel of the erector is the position of the erector on its horizontal plane in relation to the center of the scope body. If one scopes erector is closer to center you will have more erector travel. However, if the other scopes windage is dialed a bit off center it will contact the internal wall of the scope tube sooner during it's vertical travel limiting it's range of adjustment.

Not all receiver base holes are drilled dead center on factory rifles. You will most likely resolve the issue with a canted base.

 

[Guest]

Re: Reason for near-maxed out scope travel 0moa base?

I've seen more than one barrel clocked wrong, and more then one receiver milled wrong. Just because it comes from the same line does not mean it's same/same.

 

[dcjs]

Re: Reason for near-maxed out scope travel 0moa base?

It is not generally correct that maxing out elevation will limit windage travel, it depends on the internal design of the scope.

It is possible to build the scope with a rectangular adjustment range so that the full specified windage adjustment range is available at any elevation setting. This also ensures that there is at no time strain on the erector because it is pushed against the tube wall. Of course you generally only run into this problem with lots of elevation dialed in, but this is exactly when big windage adjustments are also most likely to be necessary.

In this illustration, both scopes have the same maximum elevation range <span style="font-weight: bold">a</span>. While the one on the left allows full use of the windage range <span style="font-weight: bold">c</span> throughout all elevation settings, the one on the right can only make use of the full windage range for the elevation range <span style="font-weight: bold">b</span>, which is smaller than <span style="font-weight: bold">a</span>. Dialing into the red area will result in a restricted windage range and the associated problems if the erector is pressed against the tube wall.

Now it is quite easy to see why it is so tempting for a manufacturer to not use a rectangular travel range. If the scope on the left wasn't limited to a rectangular travel range, it could offer the maximum elevation range <span style="font-weight: bold">d</span>, since there has to be enough room for this inside the tube anyway, and that room is really precious when designing the internals of a scope.

This is one of those cases where seemingly comparable numbers don't tell the whole story, and most manufacturers seem to opt for the design that will make the scope look most impressive on the spec sheet.

 

[Tomekeuro85]

Re: Reason for near-maxed out scope travel 0moa base?

David,

Good Illustration. Makes things pretty clear.

I think though that in my case this isn't the issue (at least not the whole issue)

id say about 95% or more of the adjustment range is below where I need it to be.

This can only lead me to assume that the scope is pointed up in relation to the barrel.

I know the scope is good, because I had it mounted on other rifles before.

The only new variable is his rifle/ring combo. So either his barrel is pointed down, or his rings are defective, am I correct in that assumption?

 

[craigp40]

Re: Reason for near-maxed out scope travel 0moa base?

Put your rings on his rifle with his scope and see what the result is. If the problem goes away, it's his rings. If it stays, put your scope and rings on his rifle and see what happens. If it goes away, it's his scope. If it stays I'd say the receiver is off and was not made correctly.

 

[kaborkian]

Re: Reason for near-maxed out scope travel 0moa base?

Swap the front and rear rings if that's possible