Caliber MOA

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Troy Bakel

Troy Bakel

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Feb 17, 2023
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Harrisburg, Pennsylvania, USA
1. Five shot group that edge to edge is no greater than 0.0324" + pellet caliber.

2. Caliber MOA for 0.30" = 0.3324", which is:
a. 31.75 yards or 95' 3"

3. Caliber MOA for 0.177" = 0.2094", which is 20 yards.

Have shot 0.177 sub Caliber MOA five round groups of 0.190" to 0.199" EtoE many times with my Thomas BR. Only 4 times with my FX Impact M3. Always indoors at 20 yards.

Have yet to shoot less than 0.34" EtoE with my 0.30 caliber FX Impact M3 outdoors. 3 different brands of pellets have shot 0.327" to 0.329" EtoE indoors at 20 yards, so I feel the rifle and the pellets are capable of sub 0.33" EtoE outdoors at 95'3" if I can ever get the "stool to trigger interface" to improve.
 
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1 MOA at 100 yards is 1.047"

0.01047" of MOA per yard

1 MOA at 20 yards is 0.2094"

.177 pellet would be the smallest diameter pellet that can have a five round group that is less than 1 MOA edge to edge at 20 yards.

20 yard MOA is 0.0324" in diameter greater than 0.177 caliber.

The indoor range at PSA is accurately measured to 20 yards from firing line to target backer.

As such, my standard for edge to edge five round group size when testing pellets became 0.0324" plus caliber, or what I call Caliber MOA.

The Caliber MOA Distance for 0.30 is (0.30"+0.0324") ÷ 0.01047" MOA per yard = 31.75 yards or 95'3".
 
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I get it, but i'm not sure why... I've never heard of anyone referencing the outside of the group as the group size.

For field target Troyer rating the diameter of a pellet should be accounted for in the calculations but it is too complicated to have a different Troyer rating for the three calibers. This is the one use case where I see Caliber MOA being a thing (shooting through a small hole). But its fairly unique to field target.

"As such, my standard for edge to edge five round group size when testing pellets became 0.0324" plus caliber, or what I call Caliber MOA."

So really your "Caliber MOA" group size is 0.2094", it does not make a lot of sense to say "Caliber MOA" and call out a center to center dimension (which is a non-caliber MOA way of calculating the group size).

What are you using this calculation for?
 
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JW. said:
I get it, but i'm not sure why... I've never heard of anyone referencing the outside of the group as the group size.

For field target Troyer rating the diameter of a pellet should be accounted for in the calculations but it is too complicated to have a different Troyer rating for the three calibers. This is the one use case where I see Caliber MOA being a thing (shooting through a small hole). But its fairly unique to field target.

"As such, my standard for edge to edge five round group size when testing pellets became 0.0324" plus caliber, or what I call Caliber MOA."

So really your "Caliber MOA" group size is 0.2094", it does not make a lot of sense to say "Caliber MOA" and call out a center to center dimension (which is a non-caliber MOA way of calculating the group size).

What are you using this calculation for?
Click to expand...
Center to Center group size is widest point Edge to Edge minus the outside diameter of the unshot projectile punching the hole.

The world record for a Center Fire 30 caliber five round group at 100 yards is 0.0077" Center to Center.

I keep hearing how accurate PCP rifles have become and I laugh because a 30 caliber PCP rifle is not capable of a five round group of 0.0077" Center to Center at 20 yards let alone at 100 yards.

My sub 12 Ft-lbs 0.177 caliber Thomas Precision Benchrest rifle routinely produces 5 round groups of < 0.2094" Indoors at 20 yards so to be fare to my 0.30 caliber M3, I am just scaling up the group size relative to the 0.177, which is the 20 yard MOA minus 0.177 and adding the difference to 0.30"

As for the AAFTA Troyer:

A. At 20 yards the smallest KZ diameter allowed is 0.5" having a Troyer of 40.0. This KZ is 1.50" times greater than my Caliber MOA Standard of 0.3324" EtoE for a 30 cal. .

B. At 32 yards the smallest KZ diameter allowed is 0.75" having a Troyer of 42.7. This KZ is 2.256 times greater than my Caliber MOA Standard of 0.3324" EtoE for a 30 cal.

C. At best the Troyer regulated KZ sizes are a measure of accuracy but in no way are a measure of precision.

D. I call it Caliber MOA and define it as 0.0324" + projectile caliber because it is my standard.
 
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in my limited experience, projectiles and paper do not result in a hole exactly the size of the projectile, so I don't see how these calculations can be valid. Standard is to measure CTC because that is the way to get consistent measurements.
Pointed vs dome vs wadcutter...all are going to leave different sized holes. Long grain paper, short grain paper, cardstock, chipboard, etc...all are going to respond differently when making a hole with a projectile.
Plus with CTC, the math is the same regardless of caliber.
This caliber moa idea seems to be about as reliable as a gamo scope!
 
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Troy Bakel said:
I keep hearing how accurate PCP rifles have become and I laugh because a 30 caliber PCP rifle is not capable of a five round group of 0.0077" Center to Center at 20 yards let alone at 100 yards.
Click to expand...
Why do you say a 30 cal PCP isn't capable of such a group? It's definitely neither common nor repeatable but with enough luck it's possible.
 
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