"Stupid Question" about Zero Distances

[ma smith]

What is a "proper" reference points to establish eg a100, 50 or 25 meter zero?

If I have a firing line and measure there it seems to be from the muzzle,
but if I measure from a bench, its typicaly at the back of the rifle

Assume you have a 40 inch gun (=1metre long) for a second,
the ∆ between the front and back is ~1m
so did I screw up somewhere by 1m,
depending on method chosen?

This seems like less of an issue at the usual 100m,
but its more of problem for shorter distances, eg

1% Error@100m/99m
2% Error@50m/49m
4% Error@25m/24m

 

[308pirate]

The difference is immaterial. You can't hold accurately enough for it to matter.

Get out and shoot.

 

[Dthomas3523]

Yep, doesn’t matter with centerfire. This is one of the reasons we use 100yd/m. You need to be about 15yd/m off to see a difference.

 

[GrumpyOleFart]

No substitute for time on task.
Enjoy!

 

[gunsnjeeps]

The above is the best advice.

For range layout, it is measured from the firing line to the face of the target. For range safety your muzzle is in front of the firing line, no part of your body is in front of the firing line.

 

[Deleted member 113831]

What is a "proper" reference points to establish eg a100, 50 or 25 meter zero?

If I have a firing line and measure there it seems to be from the muzzle,
but if I measure from a bench, its typicaly at the back of the rifle

Assume you have a 40 inch gun (=1metre long) for a second,
the ∆ between the front and back is ~1m
so did I screw up somewhere by 1m,
depending on method chosen?

This seems like less of an issue at the usual 100m,
but its more of problem for shorter distances, eg

1% Error@100m/99m
2% Error@50m/49m
4% Error@25m/24m

If you are doing a tall target tracking test, measure from the turrets. This is where the line of sight angle changes.

If zeroing, then from the muzzle. This is where the bullet begins to fall from line of bore.

 

[ma smith]

Thanks for all the replies

 

[_Windrider_]

The above is the best advice.

For range layout, it is measured from the firing line to the face of the target. For range safety your muzzle is in front of the firing line, no part of your body is in front of the firing line.

Technically, its from the turret of the scope to the target, but the difference from that to your muzzle isnt huge so it really doesnt matter. But the proper measurement is from the turret because thats where the adjustments are made.

OP, i use the MIL-LEO zero target available for free from Impact Data Books, the diamond gives very refined aiming points. Another good target is the champion redfield target for the same reason above but this has multiple spots on one target with adjustments to help guide you.