Find Mil Dot Calibration Magnification? (NOTOS/CHAIRGUN)

[EmptyTin_Tim]

Hello,

I have a Notos I put a 3-12x42 AO SFP Monstrum on and unfortunately the scopes instructions didn't mention at what magnification the Mil dot spacing is accurate. I also emailed and left a voicemail for Monstrum but... nothing.

I use Chairgun and for some reason it is not hitting where I am aiming when using holdover using the dots. I got CPHP going 764 fps and it is hitting about the 3rd dot at 73 yards instead of 5.05 dots down at 12X zoom. Far zero at 25 yards.

I have BC for 14.3 gr CPHP set to 0.0190. (Let me know if that needs changed too I've seen a big range online but that was their averages).

I'm wondering if maybe the calibrated magnification is NOT the normal 10x.
Can someone explain how I'd figure this out?

PS I know 73 yards is far for Notos but I have my range set up out there for my Avenger lol

I re did the scope height measurement and it's accurate now. Also I guess I could re run the FPS and see if maybe it's just shooting way faster now it's broken in more?? Would be odd. Never messed with anything HS or reg.

Any other suggestions appreciated!

Thanks!

 

[Aimright]

That always perturbs me when the manufacturers make that info hard to find or in your case impossible! One way to check its approximate value in the field would be by drawing a nice thick visible straight line on a target measuring 3.6 inches at 100 yards or 1.8 inches at 50 yards. Then look through your scope and adjust your zoom until your reticle covers the line with one mil (dot center to dot center or equivalent ), this should be your calibration magnification. I would think it probably is at either 10x or 12x.

When using a ballistics app like chairgun you will typically need to tweak some of your input to meet actual conditions. In the following post look at post #3 and Thomasairs system for field tweaking chairgun Inputs. I use a similar system in strelok and it works well for me. https://www.airgunnation.com/threads/trajectory-question.909996/

 

[Joedirt199]

Most likely at max power. Just take a yard stick and stick it up at range and see where your mildots measure. Should be 3.6" at 100 yards or half at 50 yards.

Also with a SFP you need the option to put in the power level since they will have different factors than a FFP scope. That is the beauty of Strelok.

 

[EmptyTin_Tim]

I appreciate the replies, guys!! I will grab some cardboard and measure a line and draw with a sharpie.

In Chairgun when I changed the Calibration Magnification to 12 it got closer to the 3rd dot. At ~4.42 dots now.

You can see @Joedirt199 here that chairgun lets you change the C. Mag. Let me know if you were talking about something else.


In the meantime I am thinking of replacing this scope. I can't get the parallax to focus at the distances marked like I have to use about 15 yard for actual, real, measured 25 yards. I sighted in and was drilling it 5 shots at 25 yards CPHP out of Notos
But then the next day it was off to the right but still good groups. So I'm wondering if at that 75 yards maybe my parallax is just so off I'm hitting the 3rd dot down not ~ 4.4 as Chairgun says.

 

[Joedirt199]

Yeah, that's what I was talking about. Don't get hung up on parallax markings not matching the distance where it focuses. Everyone's eyes are different and there is no way an optical company could make a scope that focuses for everyone at the exact same yardage. I think they would be better off not putting numbers on there and you just look through the scope while adjusting till focused. Immersive provides you a sticker with the numbers to add after you figure out the distance it is focused at. More expensive scopes are probably closer to the correct yardage for when focused.

 

[Squack]

The standard guideline for ranging reticle (SFP) is the highest magnification which will give the highest estimation of size. Holdover can be calculated by dividing magnification into quarters then multiplying the quarter's value for shots under 100 meters

 

[Geezerhood]

Yeah, that's what I was talking about. Don't get hung up on parallax markings not matching the distance where it focuses. Everyone's eyes are different and there is no way an optical company could make a scope that focuses for everyone at the exact same yardage. I think they would be better off not putting numbers on there and you just look through the scope while adjusting till focused. Immersive provides you a sticker with the numbers to add after you figure out the distance it is focused at. More expensive scopes are probably closer to the correct yardage for when focused.

You are 100% correct. It is impossible for the factory (or the owner!) to precisely mark a parallax wheel to indicate the parallax free setting for any specific distance that will hold true at all times and places. That position changes constantly as the temperature of the scope changes. I am not sure which way the zero parallax point moves around the wheel, closer to infinity or away from it as temperatures rise or fall, or if larger / longer scopes are more prone to more change vs smaller / shorter, but with any optic the zero parallax position on the wheel for X distance will only happen at an exact temperature. Any range markings from the factory are an approximation for convenience such as when you want to preset it to an approximate distance in advance for quick shots. This has been discovered, proven and discussed by FT shooters who, for example, carefully calibrated their wheel at 65 degrees F only to find it was no longer accurately marked at 95F. I remember reading how some FT shooters have multiple wheels that have been calibrated for various temperature ranges that they are most likely to encounter in a match.

Also, parallax focus is independent of someone's vision acuity, as is reticle focus. They can both be determined precisely with optical test equipment. At a given distance and ambient temperature the parallax setting will be at zero parallax no matter who is adjusting it. Whether that person can see that it is correctly adjusted is another story. It is much easier for some to tell than others.

Hello,

I have a Notos I put a 3-12x42 AO SFP Monstrum on and unfortunately the scopes instructions didn't mention at what magnification the Mil dot spacing is accurate. I also emailed and left a voicemail for Monstrum but... nothing.

Another thing to consider is that the actual spacing of the dots on the reticle you are using is not an actual mil at any power setting.

 

[EmptyTin_Tim]

You are 100% correct. It is impossible for the factory (or the owner!) to precisely mark a parallax wheel to indicate the parallax free setting for any specific distance that will hold true at all times and places. That position changes constantly as the temperature of the scope changes. I am not sure which way the zero parallax point moves around the wheel, closer to infinity or away from it as temperatures rise or fall, or if larger / longer scopes are more prone to more change vs smaller / shorter, but with any optic the zero parallax position on the wheel for X distance will only happen at an exact temperature. Any range markings from the factory are an approximation for convenience such as when you want to preset it to an approximate distance in advance for quick shots. This has been discovered, proven and discussed by FT shooters who, for example, carefully calibrated their wheel at 65 degrees F only to find it was no longer accurately marked at 95F. I remember reading how some FT shooters have multiple wheels that have been calibrated for various temperature ranges that they are most likely to encounter in a match.

Also, parallax focus is independent of someone's vision acuity, as is reticle focus. They can both be determined precisely with optical test equipment. At a given distance and ambient temperature the parallax setting will be at zero parallax no matter who is adjusting it. Whether that person can see that it is correctly adjusted is another story. It is much easier for some to tell than others.




Another thing to consider is that the actual spacing of the dots on the reticle you are using is not an actual mil at any power setting.

I appreciate the technical explanations guys! I understand completely. Lots of external factors come into play for precision. There needs more testing done with this particular scope, I've only had it a week but have used it daily for about 200 shots.

My UTG compact SWAT 4-16x44 is more parallax free at whatever setting and holds groups well at different distances/parallax settings on my Avenger for my eyes. I'll have to see if maybe the combination of magnification and where the side AO is set on the 3-12x42 Monstrum affects how free of parallax I can get it. It's settings are interesting it goes from I think 7.5 yards to 10 to 15 to 20 to 25 then to 50 then 100 then infinity. I understand that the markings are not to everyone's eyes but youd think it'd be like 5 yards off at 12X not 15 or so.

I understand these are not NightForce scopes but I'd like to at least keep the group centered on target each time I pick it up and dial the AO / magnification.

Maybe my eyes and this scope don't match.

Good point about maybe it isn't a real mil dot spacing to begin with. It is SFP so I know that'd affect what dot I hold at what magnification. The photo shows the reticle. In real life it is actually quite thin. But to me it looks evenly spaced.

3-12x42 V2 Tactical AO Scope

The Monstrum Tactical S31242-M-RGAO-V2 is a full-featured rifle scope ready for hunting, target practice, or tactical use with a Mil-dot reticle. Crystal clear optics with an impressive 3-12x magnification. This scope has a functionally designed Mil-dot reticle for faster range estimation and...

monstrumtactical.com

 

[EmptyTin_Tim]

Hey guys just an update for ya- I sight in at 25 yards with this Notos so I divided the 1.8" at 50 yards down to 0.9 inches at 25 yards.

The Calibration Magnification of this 3-12x42 Monstrum is 12X zoom.

I missed quite a few ground squirrel pests and decided that since I can't get this to focus right and I also want more zoom, I am going to get a different scope.

See my thread here: Vote For My Notos Scope!