Strelok

A close zero far zero issue? 10 yards is probably too close to get a "zero". 

I have a setup where it is zero at 19yards (close) and zero at 60yards (far). At 11yards the holdover is approximately 3mil (the same as 100yds).

At 10 yards your projectile is rising in an arc-like motion. At 30 yards the pellet has risen compared to its height at 10 yards.

This is due to your scope's position relative to the rifle. The rifle being below the scope requires it to be tilted slightly upward. This allows the projectile's path to intersect with the scope's line of vision at the point of zero. 

https://www.ammoland.com/2014/06/how-to-zero-your-ar-15-rifle/#axzz6Ps5ZiBh2

https://www.enfield-rifles.com/basic-bullet-trajectory-explained_topic7040.html

There a defect in strelok if you zero too closely and you get discontinuous values if your maxium trajectory height is too small. For me, ti's between 0.52 and 0.53cm. I reported it to author on 9/21/2019. Chairgun, I find, has a better implementation of calculating the optimal zero, and it can show you ballistic curve which I find instructive. Both gives apps give you the distance to your 2nd zero. Once zeroed I greatly favor strelok to calculate shooting solutions. It is just more direct and it's neat you can see a reticle that matches yours.

Sometimes a picture or two helps..

The "zero" axis of the graph is the "line of sight" (LOS). The amount the projectile starts below LOS is determined by how high you mount your scope. Line of bore (LOB) determines the launch angle. Upon launch, the projectile begins dropping relative to LOB. Usually, there will be two points along the projectile trajectory that will intersect the LOS. One near and one far. 

My best guess would be that each click is worth a different value at the different distances, for instance 1 click is ¼" at 100y but at 50y you need 2 clicks to get ¼" etc.... 

My best advice would be to zero like I do with my .22 (15.98gr@925fps) I zero at 40y then your other zero would be about 21y with less than ¼" rise between the two, then make a range card for your other distances, for me sometimes there's just not time to do all the clicking. 

Good luck John C 

Thats different. Is all your data correct? I have had no issues with Strelok so far. I usually zero at 12 myself and then dial to the range I want or hold over/under. My .22 Lelya zeroed at 12 gives me a hold under at around 2.0 at 40 yards with a nice spread where the hold changes between 1.8 - 2.2 giving me little margin for error. If I dial to say 100 yards and set it within the program that the airgun is zeroed at 100 yards. I can look back to 12 yards and its still very close click wise. 1 or 2 clicks at the most in my case. Shoot it and see if there is any major difference. 

Another guess at the discrepancy:

For these extremely close zeros (10y) even a slight error in the scope height might make a big difference.

Matthias

I understand the 2 zero thing but I don't understand why the click values are different.

If my gun's zero is 10 yards, and my target is 30 yards away, Strelok says to click 43 Down. So 43 clicks = 10.75 MOA

If my gun's zero is 30 yards, and my target is 10 yards away, Strelok says to click 51 Up. So 51 clicks = 12.75 MOA

Why would there be a difference regardless of my zero if the shooting distance is the same? If I walk 10 yards North, it takes me 11 steps. If I walk 10 yards South, it takes me 11 steps. What's the difference?

Am I just being thick-headed and missing something? Why should it matter in which direction I dial if it's the difference in distance is the same?

Click to expand...

When dealing with sight systems, there is exactly one distance that has only a single zero. In archery, this is called your "High Pin". Every other distance will have two zeros. The distance of your High Pin depends on the sight geometry and the velocity of the projectile. When you try set a pin closer than your High Pin distance, it screws up the spacing relationship to all your other pin distances, making your pin gaps appear all wonky. I wouldn't think that the concept of High Pin changes when an airgun sight system is involved. 

If the clicks you're seeing between a 10yard zero and a 30yard zero end up being different, it's probably because your 10yard zero is closer than your airgun sight system "High Pin" distance. Which really makes it a zero for a much further distance.

If you look at the reticle display in the other Strelok thread, you'll see how this might work. Reading the left side of the reticle look for 10 yards. On the right side of reticle you'll see the "real" sight in distance. Somewhere between 75 and 82 yards.

I get that too.



SkyHawk .22 zero'ed at 12 was ~2 mils hold under at 36 -40. Zeroed at 25 almost all hold Overs from 12 or so on..... IIRC its a function of the math involved

IMO one of the short comings of strelok is the lack of graphs to show the "curve". Suppose I could dump it into Excel and get that.

lbc_PSI



what program did you use to make that graph?

lbc_PSI

what program did you use to make that graph?

Click to expand...

It's from a archery ballistics program I developed for Windows and Mac desktops..SoftwareForArchersXpert (SFAX)

There a defect in strelok if you zero too closely and you get discontinuous values if your maxium trajectory height is too small. For me, ti's between 0.52 and 0.53cm.  I reported it to author on 9/21/2019. Chairgun, I find, has a better implementation of calculating the optimal zero, and it can show you ballistic curve which I find instructive. Both gives apps give you the distance to your 2nd zero. Once zeroed I greatly favor strelok to calculate shooting solutions. It is just more direct and it's neat you can see a reticle that matches yours.

Click to expand...

You realize that is the diameter of a pellet?

I understand the 2 zero thing but I don't understand why the click values are different.

If my gun's zero is 10 yards, and my target is 30 yards away, Strelok says to click 43 Down. So 43 clicks = 10.75 MOA

If my gun's zero is 30 yards, and my target is 10 yards away, Strelok says to click 51 Up. So 51 clicks = 12.75 MOA

Why would there be a difference regardless of my zero if the shooting distance is the same? If I walk 10 yards North, it takes me 11 steps. If I walk 10 yards South, it takes me 11 steps. What's the difference?

Am I just being thick-headed and missing something? Why should it matter in which direction I dial if it's the difference in distance is the same?

Click to expand...

Click to expand...

At ten yards the physical difference between 10.75 and 12.75 MOA, physically, is 0.208" That's just over 5 mm... and is is also the diameter of a pellet... Rounding errors at that range. You might be seeing something like that. If the author was calculating drop in increments of pellet diameter, you could easily get something like that happening. What happens between 130 yards and 110 yards? Does it get it right? What about something like 20 and 30?

When dealing with sight systems, there is exactly one distance that has only a single zero. In archery, this is called your "High Pin". Every other distance will have two zeros. The distance of your High Pin depends on the sight geometry and the velocity of the projectile. When you try set a pin closer than your High Pin distance, it screws up the spacing relationship to all your other pin distances, making your pin gaps appear all wonky. I wouldn't think that the concept of High Pin changes when an airgun sight system is involved. 

If the clicks you're seeing between a 10yard zero and a 30yard zero end up being different, it's probably because your 10yard zero is closer than your airgun sight system "High Pin" distance. Which really makes it a zero for a much further distance.

If you look at the reticle display in the other Strelok thread, you'll see how this might work. Reading the left side of the reticle look for 10 yards. On the right side of reticle you'll see the "real" sight in distance. Somewhere between 75 and 82 yards.

Click to expand...

Really good explanation of the pins on a bow. I never thought about it that way and I shot pins for 30 years before going back to bare bow. Well done.