Measuring scope height

[dana bodnar]

I read all of this now Iam really confused, and I dont want to take my rifle apart to find out. I need this to make sure my balistis charts have the proper information in them. It seems to me that it would be the center of the bore to the center of the scope.gun)

 

[4xforfun]

I read all of this now Iam really confused, and I dont want to take my rifle apart to find out. I need this to make sure my balistis charts have the proper information in them. It seems to me that it would be the center of the bore to the center of the scope.gun)

You are correct..the OP was asking "how do you measure it". As far as the balistic charts, and you don't want to dissasemble your setup, then guess to within 1/2 inch...which is very easy, and you will be good enough.

With a 300 yard zero you are looking at an error of 1 inch at 1000 yards....the difference between 1.5 and 2.0 inch scope height using a 140 vld at 2900 fps.

The diff is a little greater if you use a 100 yard zero.... about 4 inches at 1000 yards. Pretty much a moot point!!

Good luck and don't sweat the small stuff.

 

[HARPERC]

You are correct..the OP was asking "how do you measure it". As far as the balistic charts, and you don't want to dissasemble your setup, then guess to within 1/2 inch...which is very easy, and you will be good enough.

With a 300 yard zero you are looking at an error of 1 inch at 1000 yards....the difference between 1.5 and 2.0 inch scope height using a 140 vld at 2900 fps.

The diff is a little greater if you use a 100 yard zero.... about 4 inches at 1000 yards. Pretty much a moot point!!

Good luck and don't sweat the small stuff.

I'm glad to see someone else's numbers came out similar to mine. I was expecting more, and figured I was missing something in the program.

 

[dana bodnar]

Thanks for the info. I have a savage model 111 in the long range hunter 300 win-mag with a 5.5x22x56 knight force scope witch I built up a very nice load for and Iam trying to tighten up my group as tight as possible.gun)

 

[406precision]

Firguring scope height is simple math. Start with a disasembled gun/scope/rings/basses.

First....find the diameter of your action.....ie Rem 700 is 1.35"...divide that by 2 = .68"

Second..... figure out the diameter of your main tube on your scope and divide it by two...1" tube = .5 ....30mm tube (1.18" divide by two) =.59"

Third, measure how tall your base/ring combo is from where it mates to the reciever to the BOTTOM of the rings where the scope tube sits. lets say it is .75"

now total up your figures...1/2 dimater of action + 1/2 the diameter of the scope tube + ring/base height............ (.68 + .59 [30mm] + .75 = 2.02" scope height.

It really doesn't matter which base you measure if your rings/bases are tapered unless you are ULTRA ANAL!!! If you are, then measure both of them and divide by two the get your ring/base height.

And to the guy who said the the bullet drop is different (317.1" vs 319.1") based on scope height...HOGWASH.....bullet drop is bullet drop is bullet drop. The bullet leaves the tube and drops xxx.xxx.....the bullet does not know weather there is a scope on the gun. Now, IMPACT POINTS will be different because you are sending the bullet out on a different trajectory.

4xforfun pretty much said it. Remember a ballistic program is only as useful as the information you feed it. Field verified drops are the only way to know exactly what is happening at those distances.

If you plan to shoot to extended ranges then taking the time to collect the most accurate data possible is essential to your success.

 

[Mike 338]

I use my calipers and:

1) Measure the diameter of the barrel just in front of the scope. Divide by 2.
2) Measure the diameter of the front lens/bell. Divide by 2.
3) Measure the distance between the barrel and the scope.
4) Add 1,2 and 3, = center of the bore to center of the scope.

Close enough.

 

[seidersjoden]

Firguring scope height is simple math. Start with a disasembled gun/scope/rings/basses.

First....find the diameter of your action.....ie Rem 700 is 1.35"...divide that by 2 = .68"

Second..... figure out the diameter of your main tube on your scope and divide it by two...1" tube = .5 ....30mm tube (1.18" divide by two) =.59"

Third, measure how tall your base/ring combo is from where it mates to the reciever to the BOTTOM of the rings where the scope tube sits. lets say it is .75"

now total up your figures...1/2 dimater of action + 1/2 the diameter of the scope tube + ring/base height............ (.68 + .59 [30mm] + .75 = 2.02" scope height.

It really doesn't matter which base you measure if your rings/bases are tapered unless you are ULTRA ANAL!!! If you are, then measure both of them and divide by two the get your ring/base height.

And to the guy who said the the bullet drop is different (317.1" vs 319.1") based on scope height...HOGWASH.....bullet drop is bullet drop is bullet drop. The bullet leaves the tube and drops xxx.xxx.....the bullet does not know weather there is a scope on the gun. Now, IMPACT POINTS will be different because you are sending the bullet out on a different trajectory.

4xforfun,
Here's my predicament. I saw a previous post you responded to me on about sight height. You used rem 700 action... .68", 30mm =.59" and for an example you used 1" scope rings. Your results were was 2.27". If I add my .125" difference in scope ring height to your example I get 2.39". I figured that was easy enough but out curiosity I measured everything myself here's what I got:
For my results, I have the same scope and action but with 1.125" scope rings and by my calculation with both a ruler and calipers I'm getting a total of 2.15"-2.16" on the average.

How come my measurements were so much different. By your calculations what scope height should I technically have if I have a 700 action, 1.125" rings and a 30mm scope?

Thanks
Joden

 

[4xforfun]

4xforfun,
Here's my predicament. I saw a previous post you responded to me on about sight height. You used rem 700 action... .68", 30mm =.59" and for an example you used 1" scope rings. Your results were was 2.27". If I add my .125" difference in scope ring height to your example I get 2.39". I figured that was easy enough but out curiosity I measured everything myself here's what I got:
For my results, I have the same scope and action but with 1.125" scope rings and by my calculation with both a ruler and calipers I'm getting a total of 2.15"-2.16" on the average.

How come my measurements were so much different. By your calculations what scope height should I technically have if I have a 700 action, 1.125" rings and a 30mm scope?

Thanks
Joden

NO.......PLEASE RE READ....My result was 2.02, not 2.27.

.68 + .59+ .75 = 2.02 I used 30mm tube and 3/4 inch (.75 ring/base height)

Now, .68 + .59 + 1.125 = 2.395. The math should work IF ....IF you are measuring the ring/base height correctly. 30 mm = 1.18 inches...devide by 2 = .59. A Rem action is 1.35"..devide by 2 = .68. Those measurments are pretty much carved in stone....simple math.

Do you have one piece or two piece bases? Are they/is it tapered? If your base and rings are seperate, did you put them together and measure , or just measure each piece and add?

 

[seidersjoden]

NO.......PLEASE RE READ....My result was 2.02, not 2.27.

.68 + .59+ .75 = 2.02 I used 30mm tube and 3/4 inch (.75 ring/base height)

Now, .68 + .59 + 1.125 = 2.395. The math should work IF ....IF you are measuring the ring/base height correctly. 30 mm = 1.18 inches...devide by 2 = .59. A Rem action is 1.35"..devide by 2 = .68. Those measurments are pretty much carved in stone....simple math.

Do you have one piece or two piece bases? Are they/is it tapered? If your base and rings are seperate, did you put them together and measure , or just measure each piece and add?

Sure about that...read your own post on this sight:
http://www.longrangehunting.com/for...-my-weapon-extended-ranges-127136/index2.html

Although the math works out I'm not getting even close to those measurements when I use the several different methods out there to cross check you math?

 

[seidersjoden]

NO.......PLEASE RE READ....My result was 2.02, not 2.27.

.68 + .59+ .75 = 2.02 I used 30mm tube and 3/4 inch (.75 ring/base height)

Now, .68 + .59 + 1.125 = 2.395. The math should work IF ....IF you are measuring the ring/base height correctly. 30 mm = 1.18 inches...devide by 2 = .59. A Rem action is 1.35"..devide by 2 = .68. Those measurments are pretty much carved in stone....simple math.

Do you have one piece or two piece bases? Are they/is it tapered? If your base and rings are seperate, did you put them together and measure , or just measure each piece and add?

I have a one piece base and everything mounted, I measured base and rings from just behind the front scope mount where the ejector ports are at.

 

[7magcreedmoor]

I measure (with my calipers) the diameter of the scope tube, the diameter of the rifle bolt, divide both in half, then add the space from the top of the bolt to the bottom of the tube measured right in front of or right in back of the turret housing and that seems to work just fine. If you can't get the caliper to the bolt because your action has a closed top, then I would measure from bolt to scope right behind the receiver with the bolt retracted just enough to access the main body. Should still give decent enough data for success.

 

[seidersjoden]

I measure (with my calipers) the diameter of the scope tube, the diameter of the rifle bolt, divide both in half, then add the space from the top of the bolt to the bottom of the tube measured right in front of or right in back of the turret housing and that seems to work just fine. If you can't get the caliper to the bolt because your action has a closed top, then I would measure from bolt to scope right behind the receiver with the bolt retracted just enough to access the main body. Should still give decent enough data for success.

Thank you

 

[4xforfun]

Firguring scope height is simple math. Start with a disasembled gun/scope/rings/basses.

First....find the diameter of your action.....ie Rem 700 is 1.35"...divide that by 2 = .68"

Second..... figure out the diameter of your main tube on your scope and divide it by two...1" tube = .5 ....30mm tube (1.18" divide by two) =.59"

Third, measure how tall your base/ring combo is from where it mates to the reciever to the BOTTOM of the rings where the scope tube sits. lets say it is .75"

now total up your figures...1/2 dimater of action + 1/2 the diameter of the scope tube + ring/base height............ (.68 + .59 [30mm] + .75 = 2.02" scope height.

It really doesn't matter which base you measure if your rings/bases are tapered unless you are ULTRA ANAL!!! If you are, then measure both of them and divide by two the get your ring/base height.

And to the guy who said the the bullet drop is different (317.1" vs 319.1") based on scope height...HOGWASH.....bullet drop is bullet drop is bullet drop. The bullet leaves the tube and drops xxx.xxx.....the bullet does not know weather there is a scope on the gun. Now, IMPACT POINTS will be different because you are sending the bullet out on a different trajectory.

Read this post...read it very carfully... Paragraph five......." now total up your figures............= 2.02 scope height".... It came from THIS thread. This is also the thread in which you pulled my quote...post # 21. I may well have used differnt numbers for the ring/base height on a differnt thread..I don't know, because you didn't link there origonaly. I simply used the numbers FROM THIS POST, WHICH YOU USED AS A QUOTE.

If I use1" ring/base height then the 2.27 inch number is correct.

As far as measuring rings bases....pretty sure they need to be disasembled from the reciever to get any kind of accurate measurment.

BUT...as I have said all along.....It really dosn't matter much at all. If you are off by 1/4 inch with your scope height measurement ..say 2.15 vs 2.40...with a 300 yard zero........ you are about 3/4 of an inch off.....that is less than one tenth MOA. at 1000 yards.
Think about that for a bit!!!

 

[seidersjoden]

Read this post...read it very carfully... Paragraph five......." now total up your figures............= 2.02 scope height".... It came from THIS thread. This is also the thread in which you pulled my quote...post # 21. I may well have used differnt numbers for the ring/base height on a differnt thread..I don't know, because you didn't link there origonaly. I simply used the numbers FROM THIS POST, WHICH YOU USED AS A QUOTE.

If I use1" ring/base height then the 2.27 inch number is correct.

As far as measuring rings bases....pretty sure they need to be disasembled from the reciever to get any kind of accurate measurment.

BUT...as I have said all along.....It really dosn't matter much at all. If you are off by 1/4 inch with your scope height measurement ..say 2.15 vs 2.40...with a 300 yard zero........ you are about 3/4 of an inch off.....that is less than one tenth MOA. at 1000 yards.
Think about that for a bit!!!

You have a good point, I enjoy dorking out, out of principal to find the actually numbers, personal satisfaction I guess. I'll stick with what I came up with and call it good, I think maybe my base is shorter than what you use for your example creating different numbers.