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Question... what is the difference between 1/8 inch and 1/8 moa on scope ?

NDAR15MAN

question what is the difference between 1/8 inch click and 1/8 moa click on a up and down turret ? If you were shooting at a 1000 yard target ? Also the actual number of click difference at that 1000 yard target ? Thanks. Marty
 
The difference between 1/8" and 1/8 moa is .005875 inches at 100 yards. You can't figure out the rest until you have an actual trajectory to compare.
 
NDAR15MAN said:
question what is the difference between 1/8 inch click and 1/8 moa click on a up and down turret ? If you were shooting at a 1000 yard target ? Also the actual number of click difference at that 1000 yard target ? Thanks. Marty
Click to expand...

Meangreen is correct. I'll add this to flesh out the answer:

This is an easy 7the grade arithmetic problem once you know that one MOA is equal to 1.047" @ 100 yards.

If your scope elevation turret is truly 1/8"/click @ 100 yards, then one click would move the POI 1/8" (.125") @ 100 yards and ten times that amount at 1000 yards; i.e. 10/8" or 1.25".

If, on the other hand, your scope turret is truly 1/8 MOA/click then it would move the POI 1.048/8" @ 100 yards which is .1309". It would be 10 times that amount at 1000 yards, i.e. 1.309".

The difference between the two is 0.059" @ 1000 yards. That is about .045 clicks more or less, which is to say that 1/8"/click and 1 MOA/click is for our purposes essentially identical when it comes to real world conditions.

In fact I would guess that two identical Chinese scopes might be marketed as 1/8" by one company and 1/8 MOA by another.
 
mozella... thanks for your answer. i have a sightron III scope and it is a older model and the scope was a original 1/8 inch click scope turret. i am putting a sightron factory 1/8 moa click turret on it. internal mechanism of scope has not been changed. so i want to make sure my new 1/8 moa click turret will be accurate on this scope to 1000 yards maybe 1500 yards. do you think it will be ok to shoot 1000 yard targets with the 1/8 moa click turret with these hash marks etc on this turret ? or would you leave the orginal 1/8 inch click turret on scope scope was originally built with and sold with ? thanks Marty
 
The problem you are having is created by how you frame your description of the scope's adjustments.

They aren't 1/8" adjustments they are 1/8 MOA adjustments.

At 100 yards 1 click is 1/8 MOA which is roughly 1/8" change on the target
At 200 yards 1 click is 1/8 MOA which is roughly 2/8" change on the target (simplified to 1/4")
At 300 yards 1 click is 1/8 MOA which is roughly 3/8" change on the target
At 400 yards 1 click is 1/8 MOA which is roughly 4/8" change on the target (simplified to 1/2")
and on and on.

Yes, mathematically there is a slight error but unless you are shooting at long range or you are competing as a precision bench rest shooter it wont matter due to errors induced by the shooter and the environment. The error between a true MOA and the more commonly used Shooter's MOA (SMOA) is .047" at 100 yards and .47" at 1000 yards, forget about the true MOA values (1.047" at 100 yards) and stick with using the SMOA (1" at 100 yards).

Don't think of your range adjustments in inches when you are figuring out how to adjust your scope for a specific range, think of them in SMOA. If you know that the trajectory of your bullet drops 2 MOA between 100 and 200 yards then simply click in 2 MOA of elevation change. On the other hand, if you are trying to calibrate your scope to a new load then you'll have to understand that 2" of impact error at 100 yards is equal to 2 SMOA.

Also, verify whether your scope is setup for true MOA or SMOA. Most scope are setup for true MOA but some will have compensation for built in and the knobs actually coincide with SMOA values.
 
Last edited:
Ramac. First Thanks very much for your help. Very smart people we have on this forum , way smarter then me that is or sure.
Ha ha ha.
My scope is a Sightron lll 10-50x60.
It had a original 1/8 inch click up and down turret on it when it was built years ago now sightron 10-50x60 scope turrets are all in moa clicks I believe.
It has very very good glass on it , better then my other 3 sightron scopes for some reason. I have other sightron scopes that are 1/8 moa click turrets
So really my question is ..... for this older model scope have I done the correct thing for the “ best MATH accurate stand point shooting 1000 to 1500 yards with this scope by putting the 1/8 moa click turret on the scope. “ ????
Or ( it is perfectly ok with me )
I put the ORGINAL factory 1/8 inch click turret back on the scope because it is the most accurate turret ( hash marks numbers etc ) of the 2 turrets I have a choice between ?.
Like I say it does not matter to me really I just want to make the correct choice from a math stand point. And hoping a person that is much smarter then me can tell me which turret to choose. I am sure there is some shooters here that might have the older model sightron like I have that would also benefit from this question. Thanks again , man this is a great forum and sight.
Thanks Marty
 
The problem with this question is that the screw thread pitch built into the turret coupled with the angular distance traveled on that screw thread determines how much actual movement of the internal assemblies which then translates to the actual adjustment on target. Sightron might not have changed the turret from one to the other just the engraving.

What you need to do is a tall target test of what your actual scope does. That will answer all questions

I bet there is no mechanical difference between the 2 turrets.

David
 
Dstoenner is right. Scopes can vary and a tall target test is needed. Some will be right on and others will vary. Also the difference needed from day to day will vary. Today you might need 26 MOA to reach 1000 and tomorrow might be 25 or 28. Different conditions can change it, even in the same day. Matt
 
Ok thanks. some more good answers here. Tall turret test. Now I have to find instructions on how to do that. Ha ha ha. Marty
 
The other problem is that any error that is present in each click, will be compounded with every additional click. So if you take the clicks at face value, you may end up several feet off at 1000 yards. That is why the tall target test is needed.
 
rammac said:
The problem you are having is created by how you frame your description of the scope's adjustments.

They aren't 1/8" adjustments they are 1/8 MOA adjustments.

At 100 yards 1 click is 1/8 MOA which is roughly 1/8" change on the target
At 200 yards 1 click is 1/8 MOA which is roughly 2/8" change on the target (simplified to 1/4")
At 300 yards 1 click is 1/8 MOA which is roughly 3/8" change on the target
At 400 yards 1 click is 1/8 MOA which is roughly 4/8" change on the target (simplified to 1/2")
and on and on.

Yes, mathematically there is a slight error but unless you are shooting at long range or you are competing as a precision bench rest shooter it wont matter due to errors induced by the shooter and the environment. The error between a true MOA and the more commonly used Shooter's MOA (SMOA) is .047" at 100 yards and .47" at 1000 yards, forget about the true MOA values (1.047" at 100 yards) and stick with using the SMOA (1" at 100 yards).

Don't think of your range adjustments in inches when you are figuring out how to adjust your scope for a specific range, think of them in SMOA. If you know that the trajectory of your bullet drops 2 MOA between 100 and 200 yards then simply click in 2 MOA of elevation change. On the other hand, if you are trying to calibrate your scope to a new load then you'll have to understand that 2" of impact error at 100 yards is equal to 2 SMOA.

Also, verify whether your scope is setup for true MOA or SMOA. Most scope are setup for true MOA but some will have compensation for built in and the knobs actually coincide with SMOA values.
Click to expand...
Very well stated, nice job.

Lloyd
 
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