Measuring moa

[Tommy Cole]

Am I correct in measuring moa center to center?

 

[SnowBlaZeR2]

Are you just talking about measuring your group sizes? If so, you aren't incorrect. Some will measure from edge to edge; others from center to center. I usually measure the diameter of a single hole for the round I'm firing, then subtract that from the overall size of the group, edge to edge. Just stay consistent with your methods, and you should be good. Measuring MOA is a bit more involved, but close enough not to really matter.

 

[Arkansas Paul]

I usually measure the diameter of a single hole for the round I'm firing, then subtract that from the overall size of the group, edge to edge.

Very similar to what I do.
I measure from edge to edge at the widest point and subtract the caliber (0.308" for .30-06, 0.284" for 7mm etc.).

 

[Steve C]

I usually measure the diameter of a single hole for the round I'm firing, then subtract that from the overall size of the group, edge to edge.

One generally just subtracts the bullet diameter from the extreme outside measurement though measuring the hole would be the same. This is mathematically the same thing as measuring center to center and is considered the "proper" way to measure groups. It is also a more accurate way in that one doesn't have to guess where the center of the the outside holes are located, which can be difficult when holes over lap.

 

[SnowBlaZeR2]

One generally just subtracts the bullet diameter from the extreme outside measurement though measuring the hole would be the same. This is mathematically the same thing as measuring center to center and is considered the "proper" way to measure groups. It is also a more accurate way in that one doesn't have to guess where the center of the the outside holes are located, which can be difficult when holes over lap.

I used to just subtract the diameter of the caliber, but I found that method to be inconsistent. The diameter of the round wasn't always the exact same as the diameter of the hole it punched, depending on the target and the backer. I'm not saying you're wrong or anything, just explaining my methods.

 

[rcmodel]

Right or wrong?
I have always measured the outside edge of the two widest shots for comparison sake with the least amount of mental math making my head hurt at the range.

I even have a homemade clear plastic circle gage with ever increasing by 1/16" circles inscribed in it.
I lay it on the target and move it till all the bullet holes fit inside one of the circles.
If they fit inside the 1" circle, it's a 1 MOA group. Etc, etc, etc.


In other words, if I shoot a 3/4 MOA 5-shot group.
All five holes are inside a 3/4" circle.

Gosh!
Maybe my 1.5" groups were really 1.05 MOA groups if I subtract the bullet dia. when shooting .45-70 caliber?

rc

 

[SnowBlaZeR2]

Gosh!
Maybe my 1.5" groups were really 1.05 MOA groups if I subtract the bullet dia. when shooting .45-70 caliber?

rc

Well, you forgot to factor in that 1" is not exactly 1 MOA.

 

[rcmodel]

Pretty close though.

Yes, I know.
Close only counts when playing 'Horseshoes' or Throwing Hand Grenades.

And also measuring & writing about your latest rifles sub-MOA capability on the internet!

rc

 

[SnowBlaZeR2]

Pretty close though.

Yes, I know.
Close only counts when playing 'Horseshoes' or Throwing Hand Grenades.

And also measuring & writing about your latest rifles sub-MOA capability on the internet!

rc

Some of my shooting buddies are Scout Snipers. I need all the help I can get!

 

[rcmodel]

So, your Buddy's are Scout/Snipers huh?

That must be a pretty Low Drag/High Speed crowd you're running with I guess, I betcha!!!

rc

 

[SnowBlaZeR2]

So, your Buddy's are Scout/Snipers huh?

That must be a pretty Low Drag/High Speed crowd you're running with I guess, I betcha!!!

rc

Well, most are former teammates. I don't get to see them as much anymore since I left active duty.

 

[gamestalker]

So, like RC my groups are actually a bit tighter than I thought, like one bullet diameter tighter, cool.

I've been claiming 1/2"-ish groups, when in fact they have been roughly .216" with the 7mm RM's, I'm stoked now.

GS

 

[Jim K]

Any "official" groups are measured center to center of the widest spaced holes. The main reason for doing it that way is that the bullet diameter doesn't matter.

Jim

 

[MCMXI]

Am I correct in measuring moa center to center?

Yes, group size is determined by measuring the greatest distance center to center of all shots in the group. Any method that does this accurately is valid. As has already been mentioned, one of the least consistent methods is measuring outside to outside and subtracting the bullet diameter. I use OnTargetCalc to measure all groups since it has proven to give the most accurate results in addition to providing a lot of additional information that is very useful for load development.

 

[ford8nr]

The 'proper' way to measure 'internet groups' is to fire 20 rounds, measure the closest 2 holes and subtract TWICE the bullet diameter.

(Read sarcasm).

 

[Arkansas Paul]

Ha, ford8nr I believe that.