SIGforum
Non-optic scope control question (updated with more pictures as requested)

This topic can be found at:
https://sigforum.com/eve/forums/a/tpc/f/630601935/m/9630029874

January 22, 2021, 06:36 PM
BB61
Non-optic scope control question (updated with more pictures as requested)
Over the years, I’ve always had the basic scope. Either a fixed power or a variable power. A few years ago, I had a client give me this scope towards an outstanding bill. I’ve never mounted or used it and I don’t have the instructions and we’ve lost contact. So, questions regarding its operation.

There are multiple adjustable distance settings at the end of the scope. Do they adjust the impact based upon the distance? So, for example, if I sight the scope in at 100 yards and then I’m shooting a target at 300 yards, do I simply rotate to the 300 yard setting so I don’t have to adjust for a holdover?

At the front of the scope are the + and - symbols. Are these for fine tuning the focus?

I’m sure these are basic questions for many of you but for this old-timer, not so much.

Thanks in advance.

This message has been edited. Last edited by: BB61,


__________________________

January 22, 2021, 07:17 PM
Brother
Is that a rotating part up front, maybe for parallax adjust?
January 22, 2021, 07:41 PM
BB61
Yes. It rotates similar to the dial for the variable power.


__________________________

January 22, 2021, 07:47 PM
sigfreund
That is an older design that has an adjustable objective. The adjustment changes the parallax setting just as the more common side knob adjustments do on modern scopesights. The number settings on the objective ring are to allow setting the parallax for the indicated distances to the target. In my experience with AO scopes, though, they are usually only approximately correct and may require fine tuning to eliminate the parallax shift completely. The AO ring has nothing to do with the trajectory adjustment; that must be set with the windage and elevation knobs.

The + and – marks on the eyepiece ring are just to provide a rough guide to adjusting the reticle focus. I have never found them of any true value, especially as there’s usually no way of knowing how the focus must be adjusted for one’s individual eye except by trial. Most eyepiece adjustment rings I have seen don’t have such marks.

What brand is the scope, and what is its magnification power range?




6.4/93.6

“Wise men talk because they have something to say; fools, because they have to say something.”
— Plato
January 22, 2021, 09:22 PM
fritz
quote:
Originally posted by BB61:
So, questions regarding its operation....

The ring at the front of the scope is your parallax adjustment. The numbers represent distances to the target -- more or less -- maybe. They are rarely exact, and depending upon your eyesight they might not even be close.

The +/- ring at the back of the scope is your focus adjustment. After mounting the scope, here's the way to set the focus to your eyesight:
- Rotate the ring at the front to infinity.
- Point the scope at a white or light-colored background. A blank wall works well indoors. A featureless overcast sky works well outdoors.
- Look briefly at the reticle through the scope. Adjust the +/- ring at the back of the scope to put the reticle in focus. Don't stare at the reticle for more than a second or two -- as your eyes will adjust and make the reticle artificially sharp.
- Look away from the scope. Focus your eyes on both close and distant objects. Then look through the scope again. If the reticle isn't crisp, do a quick adjustment with the +/- ring. Then look away again. Keep repeating this cycle until the reticle is immediately crisp upon looking through the scope.

Assuming your eyesight or glasses prescription doesn't change, lock the focus ring to that good setting. If this isn't possible, make a small line with some kind of white-colored marking device to show where it's good.

The turret the faces up, is just forward of the +/- ring, and has a cap that can be unscrewed with a coin -- most likely this is your illumination knob for the reticle. It likely holds the battery.

Your turrets appear to be capped, which means they must be unscrewed for adjustments. The one that sticks up is for elevation. The one that sticks out to the right is for windage.

I suspect your turrets are intended to be used only (or maybe primarily) for zeroing -- not for compensating for elevation or windage while shooting. We need to the scope up close without the caps to determine your shooting & aiming options. The name and model of the scope will help.

Knowing the type of reticle will help, too.
January 22, 2021, 09:26 PM
BB61
The scope is a Christensen Optics. The history behind it is somewhat interesting. My friend/client who gave it to me was a partial owner in the company which was started around 10-15 years ago IIRC. It was a start up group and they were trying to design and build optical products to compete with upper tier companies (Swarovski, Leica, Zeiss). The optics, in my opinion, were not as good as a Swarovski but they are nice. They company ultimately folded when their main investor pulled out. This scope also has an illuminated reticle with 11 settings and is 6x24. I have another Christensen scope that is 3x9 non-illuminated. I also have a spotting scope and a 10x42 binocular. I’m debating on taking a 3x9 Leupold scope off of a Winchester 300 WM, that was re-barreled by Christensen Arms, with a carbon fiber wrapped Shilen select match barrel and replacing it with this scope. Frankly, the 3x9 Christensen scope has better optics than the Leupold too. So, the question really is which Christensen scope should I mount on my rifle.


__________________________

January 22, 2021, 09:35 PM
BB61
I'll get some more pictures of the turrets with the caps off in just a bit. Fascinating discussion. Thanks for all the replies.


__________________________

January 22, 2021, 09:45 PM
BB61
Pictures of the turrets:







__________________________

January 22, 2021, 09:48 PM
BB61
A couple of pictures of the binoculars. They have a rubber like coating which is nice when it is cold or wet.







__________________________

January 22, 2021, 10:14 PM
fritz
The turret picture helps. Your elevation adjustments are in 1/8 MOA. That tells me the scope was aimed at the paper-target shooter. Most MOA-based scopes have 1/4 MOA elevation adjustments.

You have the ability to match your sight-in with a zero on the elevation turret. I recommend your doing this. I expect you will zero at 100 yards. Assuming you don't have muzzle velocity numbers and dope tables, expect to raise your elevation for the following distances for centerfire rifle ammo:
- 1.5 to 1.75 MOA for 200 yards
- 3.5 to 4 MOA for 300 yards
- 6 to 6.75 MOA for 400 yards
Magnum calibers require a little less elevation to make the distances.
January 22, 2021, 10:24 PM
BB61
Thanks Fritz. Your comments have been very helpful! The same to everyone else too!


__________________________