center of scope to center of rifle bore
- Thread starter Lowholer
- Start date
Close enough is close enough.
Now ask about whether sloped bases/mounts matter.
Now ask about whether sloped bases/mounts matter.
If you ever wonder how much a certain input matters, just enter different scenarios into it and look at the changes.
Use a dial caliper...or a digital caliper.
1) Take your bolt out of your rifle and measure the diameter. Divide this number by 2 and write it down.
2) Measure your scope body outer diameter. Divide this number by 2 and write it down.
3) Place the bolt back in the rifle and close the bolt. Measure the distance from the top of the bolt to the bottom of the scope and write that number down.
4) Add those 3 numbers together and you have your center of bore to center of scope about as accurate as you are ever going to get and as accurate as you will ever need. It will be much closer than 1/16".
The ballistic apps are great and I use them but nothing beats actually pulling the trigger and writing down the results under all sorts of conditions, rain, cold, hot, uphill, downhill, on top of the mountain, down in the canyon.
1) Take your bolt out of your rifle and measure the diameter. Divide this number by 2 and write it down.
2) Measure your scope body outer diameter. Divide this number by 2 and write it down.
3) Place the bolt back in the rifle and close the bolt. Measure the distance from the top of the bolt to the bottom of the scope and write that number down.
4) Add those 3 numbers together and you have your center of bore to center of scope about as accurate as you are ever going to get and as accurate as you will ever need. It will be much closer than 1/16".
The ballistic apps are great and I use them but nothing beats actually pulling the trigger and writing down the results under all sorts of conditions, rain, cold, hot, uphill, downhill, on top of the mountain, down in the canyon.
If you hate math, there's always this option.
Measure from the center of your ring gap to the vent hole if it's a Remington action.
That's your number.
And yes, those are UTG rings and they are fantastic for under $60.
They belong to this rifle.
Measure from the center of your ring gap to the vent hole if it's a Remington action.
That's your number.
And yes, those are UTG rings and they are fantastic for under $60.
They belong to this rifle.
Close enough is close enough.
Now ask about whether sloped bases/mounts matter.
Okay, I'll ask the question.
Do they matter?
I've always wondered if it does.
Where do you measure with a sloped base?
Front ring?
Rear ring?
Split the difference....?
I've never bothered to check it and maybe that's why the only rifle that ever lined up correctly was my 8t 6-BR with zero MOA bases...
I didn't have to mess with velocity or BC for it to line up.
It gets shot out to 1200 so I don't need extra elevation with the XRS-2 on top.
Inquiring minds want to know.
Say 5.7” front of rail to back.
20MOA = .3333 degrees (repeating, of course)
Tan(.33333) = Delta height/5.7
.00582*5.7 = .0332
If the mechanical housing is in the middle, and you measure at the front or back, you’re off by half of that, so .017”…. should you care? No, not really.
Too much math that involves names, letters parenthesis, formulas and whatnot.
I'm 40 years out of high school and never used all of that stuff, so it's Greek to me and probably a lot of others.
If I had to guess where it counts, I'd measure at the turrets and call it good.
I usually measure to the rear side of the front ring, input the data and go shooting.
I zero best that I can and true as I go out.
I still have all my hair, so it must work okay.
Greg, what are your observations?
Doesn't matter.
I measure in the middle of the rail just to make sure I'm splitting the difference just to keep that little OCD baby in my brain happy. 
