Tunning my Balistic Caculator

[ranger116]

I do a lot of critter hunting 300 yards & out, and I need some advise on how to accurately measure your Sight Height?
I assume you measure from the center of the bore to the center of the cross hairs, and that's what I've tried, but with tubes from 26'' to 30'' is the a trick?

 

[seanhagerty]

You want to measure the height at the front of the scope. Basically measure from the centerline of the barrel to the centerline of the scope at the front of the objective lens.

Sean

 

[necchi]

Use your caliper to measure the diameter of the barrel,,
1/2 of the diameter is the center of the bore,,
or
1/2 the diameter added to the hight from outside the top of the barrel to center of scope

 

[4xforfun]

First off, of all of the imputs you put in your program, sight height is proboably the least important. According to my Sierra I6 program, 1/2 inch difference in sight height with a 300 yard zero = 1.1 inch difference at 1000 yards.

Now, if you are as anal as I am you check this way.


1/2 action diameter (radius)

plus

1/2 scope TUBE diameter (radius)

plus

the measurement from the bottom of the scope base (where it fits to your action) to the bottom of the bottom ring (where your scope sits).

If you are SUPER ANAL, and you have a tapered base or tapered rings, simply add the last measurement on both bases, add them together, and divide by two and add that number to your scope tube and action radius.

 

[alf]

Or just take a ruler and measure from the top of the stock at the action to the gap in the scope rings.......

 

[4xforfun]

Or just take a ruler and measure from the top of the stock at the action to the gap in the scope rings.......

Not NEAR anal enough for me.

 

[lpreddick]

4xforfun is right for a 300 yd zero. for a 100 yd zero the difference becomes much more...like 1/2 min (5 in at 1000 yds) for 1/2 in difference in sight height. most of my shots are under 400yds so i use a 100 yd zero and have to measure my sight heights carefully. my varmint targets are small.

 

[bheadboy]

Alf, my system also, works for me

Bob

 

[alf]

Alf, my system also, works for me

And you certainly can get closer than a 1/2". :

Takes me longer to find the ruler......

 

[timeout]

Use your caliper to measure the diameter of the barrel,,
1/2 of the diameter is the center of the bore,,
or
1/2 the diameter added to the hight from outside the top of the barrel to center of scope

I presume that since the barrel is tapered, it would be necessary to measure top of barrel to center of scope, at the identical place the O.D. measurement of the barrel was taken. If the barrel O.D was measured at the muzzle and the scope center was measured at some distance up from the muzzle, the amount of taper between those two points would need to be added.

 

[bheadboy]

if you really really want to go to all the trouble, here is how you can do it

take the stock off, use calipers to measure the distance from the bottom of the action ring(behind the recoil lug) to the top of the scope tube. keep this number a "1"
measure the diameter of the action at the same point - divide by 2 keep this number as "a"
divide the scope tube diameter by 2 and keep this number as "b"

now take "1" and subtract "a" and "b" = the number you want

Bob

 

[lpreddick]

now we're talking ANAL! is your measuring device OCD approved?

 

[4xforfun]

4xforfun is right for a 300 yd zero. for a 100 yd zero the difference becomes much more...like 1/2 min (5 in at 1000 yds) for 1/2 in difference in sight height. most of my shots are under 400yds so i use a 100 yd zero and have to measure my sight heights carefully. my varmint targets are small.

Wow, I guess I never considered a 100 yard zero!! You are right...about five inches at 1K. I know that that really isn't that big a deal at 1k...but like I said....I'm kinda anal.

Good call,
Tod

 

[bheadboy]

lpreddick - oh my, i dont know --what will i do if they are not, help?

said how to measure, never said i did it that way

i follow Alf method - have for years.

Bob