Greetings all,

I was wondering at what distance to set the "zero", i.e., the dot being on the optical/mechanical axes. The motivation is to allow the scope to have the minimum and close to symmetrical amount of adjustment from the chickens to the rams, thus, reducing stress on a scope.

Since the chickens are at 40 m and the rams at 100 m, my simplistic thinking, ignoring the change in trajectory, is at the middle, i.e. 70 m. One can then either go down from there to the chickens or up to the rams or, alternatively, to prevent such a complication, to reset the turrets at numerical "zero" at either the chickens or the rams.

Any advice would be appreciated.

Kindest regards,

M

I think I understand what you're asking so I'll give it a shot.

Let's assume you can mechanically adjust your scope outside of the internal scope adjustments, such as by using an adjustable scope mount.

You would first determine how much elevation you need between chickens and rams. Let's just say for your rifle and ammo you need 8 MOA. Set your scope's internal adjustment down half of that distance (4 MOA down) from its internal perfect center and mechanically adjust the scope mount so a bullet hits center of target at 40 meters.

Now, when you adjust the scope up 4 MOA back to center and another 4 MOA (8 MOA total) you should be hitting targets at 100 meters. The scope's internal adjustments are now -4 MOA to +4 MOA from it's internal center and as balanced as you can get given the requirements. If your ammo/rifle shoots 7.5 MOA between chickens and rams then you would split it -3.25 MOA and +3.25 MOA. Make sense?

Bringing us out of the theoretical world and back into real-world practicality... as long as you're not at the extremes of your scope's internal adjustments then you're just fine. It's fairly common to have to use a small shim in the back scope ring to go from chickens to rams with some wiggle room at both ends.

Remember: It's fine to think through the theoretically perfect scenario but don't live there, you'll only be disappointed with life.

acorneau wrote: Sat Jun 05, 2021 12:53 pm Remember: It's fine to think through the theoretically perfect scenario but don't live there, you'll only be disappointed with life.

Truth spoken here.....

Hi acorneau,

that is exactly what I had in mind. And yes, I can adjust the scope relative to the barrel by means of inserts into Zee rings.

Regarding your warning about the difference between the theory and practice, I am aware of it, so I understand that the method will not yield perfection. But, at least I will stay out of the extremes.

Kindest regards,

N

I use the Zee rings to zero the scope in the middle of the adjustment range of the animals while leaving the scope mechanically in the center of the turret adjustment range like you're describing. I then adjust down to chickens and reset my turret cap to zero.

Is it necessary? No.

Has it ever gained me an animal? No.

Does it make me feel more comfortable twisting on my turrets knowing I'm no where near the extreme ends of the range? Yes.

Hi Doodaddy,

Doodaddy wrote: Sun Jun 06, 2021 9:10 am Does it make me feel more comfortable twisting on my turrets knowing I'm no where near the extreme ends of the range? Yes.

Exactly. Given the scarcity of scopes, I want mine to last as long as possible.

Kindest regards,

N

nemo wrote: Sun Jun 06, 2021 1:37 pm Hi Doodaddy,

Doodaddy wrote: Sun Jun 06, 2021 9:10 am Does it make me feel more comfortable twisting on my turrets knowing I'm no where near the extreme ends of the range? Yes.

Exactly. Given the scarcity of scopes, I want mine to last as long as possible.

Kindest regards,

N

100%

Burris says that a scope is its clearest at the center of the adjustment range and that clarity deteriorates as you move away from it which is why they designed the Pos Align inserts. If that's true, I've never been able to tell, but like we said before the inserts keep me away from the end of adjustments. I also don't have to lap these rings and have never left a ring/mark on a scope either.

They're the only rings I use assuming I can afford the weight, but I always make sure I can lol.

Hi Doodaddy,

Doodaddy wrote: Mon Jun 07, 2021 8:22 am Burris says that a scope is its clearest at the center of the adjustment range and that clarity deteriorates as you move away from it . . .

In my understanding, this is correct as witnessed by looking at tests of sharpness of camera lenses, which are designed with the goal to be sharp across the entire field. However, whether one can observe the loss of sharpness in the rifle scope is a question.

But, as noted, my concern is minimizing the mechanical stress.

The posi-align rings are ingenious - allowing for barrel axis/scope axis alignment without placing stress on the scope tube and protecting the scope.

Kindest regards,

N

nemo wrote: Mon Jun 07, 2021 11:19 amIn my understanding, this is correct as witnessed by looking at tests of sharpness of camera lenses, which are designed with the goal to be sharp across the entire field. However, whether one can observe the loss of sharpness in the rifle scope is a question.

I generally deal with portrait prime lenses, but what lenses are you adjusting reticles in?

Hi Doodaddy,

Doodaddy wrote: Mon Jun 07, 2021 1:01 pm I generally deal with portrait prime lenses, but what lenses are you adjusting reticles in?

None. but my point was that even photography lenses, are sharper around the center, and softer towards the circumference, cf. the tests in, e.g., Popular photography, Ken Rockwell web page, etc. This is akin to moving the reticle from the center towards the circumference.

Does it make sense?

Kindest regards,

N

nemo wrote: Tue Jun 08, 2021 10:05 am Hi Doodaddy,

Doodaddy wrote: Mon Jun 07, 2021 1:01 pm I generally deal with portrait prime lenses, but what lenses are you adjusting reticles in?

None. but my point was that even photography lenses, are sharper around the center, and softer towards the circumference, cf. the tests in, e.g., Popular photography, Ken Rockwell web page, etc. This is akin to moving the reticle from the center towards the circumference.

Does it make sense?

Kindest regards,

N

It does. Just wanted to make sure I was reading you right.

Not only have I noticed clarity changes along the FOV of a lense, the optical distortion increases, and usually vignetting kicks in as well. A lot can be corrected in post, but I try not to lean on that too much. I'd rather not shoot wider than 50mm, but my wife lives on a 35mm lol.

Doodaddy wrote: Wed Jun 09, 2021 10:27 am
Not only have I noticed clarity changes along the FOV of a lense, the optical distortion increases, and usually vignetting kicks in as well. A lot can be corrected in post, but I try not to lean on that too much. I'd rather not shoot wider than 50mm, but my wife lives on a 35mm lol.

We are getting rather off-topic, I hope the moderators do not mind. Yeah, since you mentioned portraits, I understand your focal-length choice. I used to carry camera to the mountains, and thus preferred (and still do) 24 mm.

One way to deal with the different optical errors is buy a good lens, which usually equals money and weight.

Kindest regards,

N

nemo,
You're right this is getting down in the weeds. Lenses aberration is probably the least of anyone's problem when shooting silhouette. If the scope is properly centered within reason through the animal range things like ammo, hold, barrel quality, etc. are the major factors one should be thinking about.
ppkny

nemo wrote: Thu Jun 10, 2021 11:56 am

Doodaddy wrote: Wed Jun 09, 2021 10:27 am
Not only have I noticed clarity changes along the FOV of a lense, the optical distortion increases, and usually vignetting kicks in as well. A lot can be corrected in post, but I try not to lean on that too much. I'd rather not shoot wider than 50mm, but my wife lives on a 35mm lol.

We are getting rather off-topic, I hope the moderators do not mind. Yeah, since you mentioned portraits, I understand your focal-length choice. I used to carry camera to the mountains, and thus preferred (and still do) 24 mm.

One way to deal with the different optical errors is buy a good lens, which usually equals money and weight.

Kindest regards,

N

I see the topics as cousins at least. A camera lens and a rifle scope are pretty similar in many ways.

Your last point rings very true in both the camera world as well as shooting sports. Unfortunately we're pretty limited in scope choices. First by weight, then by reticle, and always looming in the background is repeatable turrets. A rule of thumb many live by is to spend on the scope what the rest of the rifle cost so that the scope quality is deserving of the rifle. While that's a crude way of determining budget in my opinion, I do think there is some truth in the concept. Sadly the current market of high end scopes simply aren't options for silhouette. I'd love a Kahles or Nightforce or something along those lines, but their 34mm tube scopes are halfway to the hunterclass weight limit! I'm exaggerating of course, but barely LOL

ppkny wrote: Fri Jun 11, 2021 6:46 am nemo,
You're right this is getting down in the weeds. Lenses aberration is probably the least of anyone's problem when shooting silhouette. If the scope is properly centered within reason through the animal range things like ammo, hold, barrel quality, etc. are the major factors one should be thinking about.
ppkny

I think you're completely right, but I will say I find chromatic aberration pretty distracting in the right conditions. Bright sunlight on white animals in the morning drives me insane. My problem alone and I don't think any scope would fix it more than another.

Hi Doodaddy, ppkny,

I really do not upset the moderators, but I have no issue believing that Doodaddy and other people may find lens distortion an issue. I am basing it on my own observation, wherein my landlord notices distortion in (photographic) lenses that I simply do not see until he points them out. At the same time, I could tell a difference in optical quality between two scopes.

Kindest regards,

N