MOA vs MRAD at 100 Yards: A Practical Zeroing Reference

Most of the MOA versus MRAD argument is tribal. Almost none of it matters at the bench. What matters is knowing what your own turret does, and being able to turn a miss measured in inches into a number of clicks without doing trigonometry in the wind.

Here is the short version, with the numbers.

The two angles

Both are angular units. Both open up with distance. Neither is better.

MOA, minute of angle, is one sixtieth of a degree. At 100 yards it subtends 1.047 inches. People round that to one inch and call it close enough, which it is at 100 yards and is not at 600.

MRAD, milliradian, is one thousandth of a radian. At 100 yards it subtends 3.600 inches. Metric shooters usually think of it as 10 centimetres at 100 metres, which is the same relationship in tidier numbers.

Both scale linearly with distance. That is the only property you need. Double the distance, double the subtension.

What one click moves

This is the number that actually gets used, and it depends on your turret, not on the unit.

| Turret | One click at 100 yd | At 200 yd | At 300 yd | |---|---|---|---| | 1/4 MOA | 0.262 in | 0.524 in | 0.785 in | | 1/8 MOA | 0.131 in | 0.262 in | 0.393 in | | 0.1 MRAD | 0.360 in | 0.720 in | 1.080 in |

A quarter MOA click and a tenth MRAD click are close enough in size that neither gives you a meaningful precision advantage at ordinary distances. A 1/8 MOA turret is finer, and mostly matters for benchrest work.

Turning a miss into clicks

The whole job at the bench is this: you have a group, it is some number of inches from where you wanted it, and you need a click count.

Clicks = miss in inches ÷ what one click moves at that distance.

Two worked examples.

You are 3 inches low at 100 yards with a 1/4 MOA turret. 3 ÷ 0.262 = 11.45, so 11 clicks up. Round to the nearest click. There is no half click.

You are 5 inches right at 200 yards with a 0.1 MRAD turret. One click moves 0.720 inches at 200 yards. 5 ÷ 0.720 = 6.94, so 7 clicks left.

That arithmetic is trivial at a desk and annoying at a bench in a crosswind with cold hands. It is why a printed correction table beats a formula: read the miss off the grid, run your finger across the row, dial the number.

Reading group size in MOA

The other number worth having:

Group MOA = group size in inches × 95.5 ÷ distance in yards.

A 1.5 inch group at 200 yards is 1.5 × 95.5 ÷ 200 = 0.72 MOA.

Measure centre to centre on the two widest holes, not edge to edge. Edge to edge inflates every group you have ever shot by one bullet diameter.

The honest note about inch grids

A one inch grid is not an MOA grid. At 100 yards, one inch is about 0.955 MOA. Plenty of targets round that away and label an inch grid as MOA, which introduces a quiet four and a half percent error into every correction read off it.

You can work in inches and convert, or you can work in MOA directly. Both are fine. Mixing them without noticing is not. The fix is that the sheet should say which one it is printing.

Zeroing procedure, briefly

1. Shoot a three or five shot group. Do not chase individual shots. 2. Find the centre of the group, not your best hole. 3. Measure horizontal and vertical distance from group centre to point of aim, in inches. 4. Convert to clicks at your distance using the table above. 5. Dial, then shoot a fresh confirming group. Never adjust off a group you have already adjusted from.

And the part that has nothing to do with math: write it down. Date, rifle, optic, load and lot, distance, temperature, wind. Zeroes drift and ammunition lots change, and a target with no data on it is just paper with holes in it.

Every sheet in the Precision Zero Pack carries correction tables computed from these figures at each listed distance, in both MOA and MRAD, plus a range log block. For keeping the record across seasons, see The Owner's Record.