Hello everyone.
I wanted to "reach out" with my 2240, so I had to know how much adjustment I had on my turrets. This gun has a Hawke Vantage 4-16x50 scope that has an elevation turret range of 80MOA, or 320 clicks. My gun was zeroed at 50 yards, and it ended up being 239 clicks, or 59.75MOA adjustment, so I was almost out and needed to change over to adjustable rings. I got these from WestHunter. So now I am wondering how much to cant my scope to get it in range. Here is a link to a discussion on AccurateShooter forum and they discuss how to calculate it. My take-away from this is that there are four numbers that we are working with:
0.000291 = Constant
Distance Between Rings in Inches
Desired MOA Adjustment
Difference between rings in height
Formula:
Constant x Distance between Rings x Desired MOA adjustment = Difference between Rings in height
So, for example, if your rings are 4" apart, and you want a 20MOA adjustment, you do the following:
0.000291 x 4 x 20 = 0.023" in between the rings
My original rings had a shim in the back that was 0.019" thick. Reversing this formula we get:
0.019/(0.000291 x 4) = 16.32MOA, so my shim was giving me just over 16MOA of cant
So, I was adjusted up 59.75MOA on the turret, and had an additional 16.32MOA from the shim, so my scope was adjusted 76.07MOA to get zeroed at 50 yards.
Now, back to the WestHunter rings. They have six positions that they can be adjusted to, and this moves the ring up by 0.248", but there is 0.002" of "slop" in the adjustment, so I will use 0.250" because it is a nice round number.
0.250" / 6 positions = 0.04167" per adjustment
The calculation for each adjustment is:
0.04167 / (0.000291 x 4) = 35.7989MOA or (basically) 36MOA per adjustment
If I adjust it up two positions, it will give me 72MOA of adjustment, which means that when I adjust my turret all the way to the bottom, it will be zeroed somewhere just shy of 50 yards. I very frequently zero this gun in at 25 yards, so two positions will be too much for my usual shooting scenario, so I will only raise it one position. This ultimately means that my adjustment went from 16MOA to 36MOA, so I will have more than doubled my adjustment by going from the shim to the adjustable rings.
I have a few different versions of these adjustable rings, so I'll plan to put a caliper on them too, to see if the adjustment per position is basically the same, but they all operate the same, so I don't expect much of a difference.
I'm an engineering nerd, so this stuff is fascinating to me. I hope that it helps some of my airgunning brethren. Even if you just take my word for it, you now know that each adjustment of these adjustable rings gives you about 36MOA of adjustment when the rings are 4" apart.
Cheers!
Jonathan
I wanted to "reach out" with my 2240, so I had to know how much adjustment I had on my turrets. This gun has a Hawke Vantage 4-16x50 scope that has an elevation turret range of 80MOA, or 320 clicks. My gun was zeroed at 50 yards, and it ended up being 239 clicks, or 59.75MOA adjustment, so I was almost out and needed to change over to adjustable rings. I got these from WestHunter. So now I am wondering how much to cant my scope to get it in range. Here is a link to a discussion on AccurateShooter forum and they discuss how to calculate it. My take-away from this is that there are four numbers that we are working with:
0.000291 = Constant
Distance Between Rings in Inches
Desired MOA Adjustment
Difference between rings in height
Formula:
Constant x Distance between Rings x Desired MOA adjustment = Difference between Rings in height
So, for example, if your rings are 4" apart, and you want a 20MOA adjustment, you do the following:
0.000291 x 4 x 20 = 0.023" in between the rings
My original rings had a shim in the back that was 0.019" thick. Reversing this formula we get:
0.019/(0.000291 x 4) = 16.32MOA, so my shim was giving me just over 16MOA of cant
So, I was adjusted up 59.75MOA on the turret, and had an additional 16.32MOA from the shim, so my scope was adjusted 76.07MOA to get zeroed at 50 yards.
Now, back to the WestHunter rings. They have six positions that they can be adjusted to, and this moves the ring up by 0.248", but there is 0.002" of "slop" in the adjustment, so I will use 0.250" because it is a nice round number.
0.250" / 6 positions = 0.04167" per adjustment
The calculation for each adjustment is:
0.04167 / (0.000291 x 4) = 35.7989MOA or (basically) 36MOA per adjustment
If I adjust it up two positions, it will give me 72MOA of adjustment, which means that when I adjust my turret all the way to the bottom, it will be zeroed somewhere just shy of 50 yards. I very frequently zero this gun in at 25 yards, so two positions will be too much for my usual shooting scenario, so I will only raise it one position. This ultimately means that my adjustment went from 16MOA to 36MOA, so I will have more than doubled my adjustment by going from the shim to the adjustable rings.
I have a few different versions of these adjustable rings, so I'll plan to put a caliper on them too, to see if the adjustment per position is basically the same, but they all operate the same, so I don't expect much of a difference.
I'm an engineering nerd, so this stuff is fascinating to me. I hope that it helps some of my airgunning brethren. Even if you just take my word for it, you now know that each adjustment of these adjustable rings gives you about 36MOA of adjustment when the rings are 4" apart.
Cheers!
Jonathan