Rifle Scopes Really Confused

[rick23]

My friend has just bought an IOR scope and slapped it onto his TRG. before that he had a S&B PM 3-12. Now when he moves back from 300 to 600 he has to put on 1.3 mil, before he had to put on 31 clicks. the IOR is in 0.1Mrad and the S&B says "1 click = 1cm" now going by my maths, 1cm at 100m is 0.1 mil, or thereabouts. Anyone have any ideas why there is a difference. It's really confusing and we've spent the last couple of days sitting and trying to work out why there is a difference.

Any help would be great
Cheers
Rick

 

[Rob01]

The S&B was also 1 click equals .1 mil but for some reason they put the metric in there. First thing is to stop thinking in clicks. It's confusing and not needed. Think in mils and use the large numbers on the dial. Have him look at his data sheet, which should be in mils and not clicks, and have him dial on whatever his 600 data should be. Not worry about how many clicks going from 300 to 600.

 

[BCP]

What model IOR? How many mils per turn? What caliber?

 

[Trespasser]

Are you sure dyslexia isn't to blame for the 1.3 mils vs. 31 clicks discrepancy?

 

[tylerw02]

Rob nailed it. Also, there may be some differences in data with the new scope depending on how well it tracks and the height over bore. You'll want to confirm all your data over again when switching scopes.

 

[kombayotch]

Assuming this is a 308 with a 100 yard zero, you need to put on about 1.3 mils (13 clicks) to go from 100 yards to 300 yards. But, you need roughly an additional 3.1mils (31 clicks) to go from 300 yards too 600 yards (4.4 mils total).

I think you are confusing what is being put on at 300 yards with what needs to be added to go to 600 yards from 300 yards.

 

[rick23]

I'm not sure which model it is to be honest, but its .308, zeroed at 300yds and I've just read its meant to say from 300 to 500, which by data takes 1.9mils, but in fact takes 1.3. When his other scope was on to go back to 500 it used to take 31 clicks from 300. Saying the S&B clicks are 0.1mils, its strange that it is so against the data sheet, he used to use an old army minutes chart and convert to mils, but it worked for him, and now he has his zeroes and its working fine.

its more of a theoretical exercise as we are wondering why there is so much different, but thanks for all the answers guys.

Rick

 

[djskit]

I does not sound like you are clear on the click value of the prior scope. I haven't done the math, but if that scope was in MOA, there would be a descrpency between that and the number of clicks on a mil scope.

 

[kombayotch]

I'm not sure which model it is to be honest, but its .308, zeroed at 300yds and I've just read its meant to say from 300 to 500, which by data takes 1.9mils, but in fact takes 1.3. When his other scope was on to go back to 500 it used to take 31 clicks from 300. Saying the S&B clicks are 0.1mils, its strange that it is so against the data sheet, he used to use an old army minutes chart and convert to mils, but it worked for him, and now he has his zeroes and its working fine.

its more of a theoretical exercise as we are wondering why there is so much different, but thanks for all the answers guys.

Rick

1.9mils makes sense with a 308 and a 175 gr. bullet. 1.9mils is 6.5 MOA, and that would only be 26 clicks with 1/4 MOA turrets. 31 clicks on a 1/4 MOA scope would be 7.75 MOA (2.25mils). Even a radical change in scope height would not account for that difference, neither would dropping the temperature well below zero.

Your old data and your calculated new data do not match up.

 

[rick23]

I'm not sure, but the data did work for him, I'll have to double check that I got the right numbers from him, but there is a radical difference, whatever the numbers are, and we are really confused!

rick

 

[tylerw02]

Really Confused

I'll bet your last time out the weather was far different. New, unproven scope, possibly new mounting height, different environmental conditions...all of it could add up also forget about inches, centimeters, etc. Start thinking in mils. Also you should always reference elevation to a 100 yard zero.

What ballistic computer? How are you gathering data for DA? Same ammo?

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