Variables,Scope mount system

Molly said:
Here's a mount I made a couple of years ago for my Turbo. I made it so I could use a BV20 scope bumped to 30 power. I wanted positive clicks and the use of known scope. I had a friend (Steve Wieck) who used the same sort of set up with Foster jewel type rings. I thought why not use the base with a Unertl scope. Hope the picture comes through.
Click to expand...

That's quite a slick setup. The only problem is that unless you've got a BV20, they are bringing some serious coin for good ones. You know off hand what the scope & mounts weigh?
 
Question

Does distance between scope mounts increase or decrease POI shift if something externally moves? thanks, joe
 
trying to learn.....

I'm reading these scope discussions on here and learning a lot but i'm getting confused. Up to now my budget has not allowed me a nice scope, just the cheeper BSA's and the like. I have always wanted something nice, i now realize my point of impact is shifting around a bit.

I read mr. jackie freezes the nicer scopes and some are going back to micrometer Unertl type mts. Then Bill says a single mt is best. Then someone posted we have gone full circle.

That got me to thinking about the old Unertl scopes with over 12" between bases. Rimfire doesn't put much heat in the bbl. With the mounts so far apart with the Unertl type scopes i was thinking and maybe i'm wrong -with the mounts being so far apart if anything moves maybe there is less POI shift. It seems to me with a single mt a slight movement would change the POI a lot more than if the mts are far apart. What am i missing here?
have we gone full circle and did Unertal have it right?
thanks joe
 
I guess you could think of it as if you only had one ring or to rings directly together. If the expansion and contraction of the scope puts stress on the action, the lesser span should cause less stress. That's considering stress on the action only and not stresses on the scope. You would think it would be the same way with the barrel and Unertl but Unertl bases used a spring which may keep the stress from transferring to the barrel. Unertl may have had it right, but they probably needed the span to support the big scope.

I think the POI moves in all of them when they are subjected to changes in heat and cold whether expensive or cheap. I've never tried a frozen scope but always wanted to; however, I've heard several say they do not work well for score. The scope stresses are an issue and some people are working on innovative ideas. Sooner or later one will hit something that works and then we'll all buy it.
 
I have three brackney mounted 45 power scopes and love all three. I traveled through two airports going to the world championships at Millan Italy last summer with no major changes to impact. The front mount is in hard rubber and is not affected by action stress. This is the only set up I have found that does not move alot from day to day. From what I understand the best optics are in center of scope. Freezing crosshairs places them in the center no mater if they need ajusted. The biggest change to get used to is there is no clicks and if this is something you need you will not like this setup.
 
Beau

The Brackney does not have 'clicks', just a smooth feel when changing elevation or windage. David has, to my knowlege, only needed to adjust the POI on one or two occasions. They seem to hold same POA/POI very well.
 
Then a shooter would not be hindered by MOA adjustments? Seems like a big advantage and a way to have a true zero.
 
what's it weigh

Tim
Sorry I did not see your post about the weight till now. I know what you mean about the cost of BV 20's they do bring serious money. I already had a couple so put it to work. I can weigh it if you are serious about using it for IR 50 but I doubt it would make weight.
 
jGEE said:
I'm reading these scope discussions on here and learning a lot but i'm getting confused. Up to now my budget has not allowed me a nice scope, just the cheeper BSA's and the like. I have always wanted something nice, i now realize my point of impact is shifting around a bit.

I read mr. jackie freezes the nicer scopes and some are going back to micrometer Unertl type mts. Then Bill says a single mt is best. Then someone posted we have gone full circle.

That got me to thinking about the old Unertl scopes with over 12" between bases. Rimfire doesn't put much heat in the bbl. With the mounts so far apart with the Unertl type scopes i was thinking and maybe i'm wrong -with the mounts being so far apart if anything moves maybe there is less POI shift. It seems to me with a single mt a slight movement would change the POI a lot more than if the mts are far apart. What am i missing here?
have we gone full circle and did Unertal have it right?
thanks joe
Click to expand...

Joe, probably the majority of guys that shoot this use Weaver 36X with few problems. Under 4 bills new.
 
Molly said:
Tim
Sorry I did not see your post about the weight till now. I know what you mean about the cost of BV 20's they do bring serious money. I already had a couple so put it to work. I can weigh it if you are serious about using it for IR 50 but I doubt it would make weight.
Click to expand...

No don't go to any trouble, I thought you might know. I'm fine with my optics now....just curious. I think for that kind of scratch, assuming you do not have one, the Leupold Comp scopes are more than enough. I never thought the 45x was really needed for rimfire but I put one that I had on a 6PPC onto my backup gun and I really do like it, picks up that subtle mirage that 36's can miss.
 
Reply to Tim

Tim
I am curious as to your use of a 45 power to see mirage. I have never had a scope of that power. I always felt that a scope of lesser power say the 30X saw mirage "flow" a little better than my 36X. I guess I will switch them around this spring and experiment. Thanks for the tip!
 
The better optic simply allows you to pick up a subtle mirage that the 36's miss. If it's a full on boil you're going to see it with anything.
 
Depth of field

Some scope have a greater depth of field than others. Short depth of field scopes, will only pick up the mirage at a set range of focus.
 
The modifier disc that comes with the March gives more depth of field.
 
Fred J said:
Some scope have a greater depth of field than others. Short depth of field scopes, will only pick up the mirage at a set range of focus.
Click to expand...

If that were as simple as that then why do the March 40's pick up mirage the 36's don't ? It's depth of field and optical quality.
 
Increasing depth of field only changes how you see the mirage. The increase in depth of field make the mirage more defined, as in more readable. Without the disc it is harder to read what the mirage is telling you. Even if you can't see it the mirage is still there, and with the mirage is a condition that can affect your shot. Lack of seeing it might not make you aim differently, like it would if you could see it.

My 40X March picks up a lot less condition than the 60X, which at times makes it easier to aim, but the 40x still picks up enough to let me know a change has occured. The 60X picks up very slight changes in the sight picture, and it will actually tell you when NOT to shoot.

I have a friend that has a 45LCS and it is a great scope, but he seems to see less mirage than I do, even when I am looking through his scope.

Everyone's eyes are different, and if you have had the pleasure of shooting with a March, there is no question of it having quality optics.
 
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