Long range zeroing at short range

[eighteenninetytwo]

Does anyone have any software or information on the ballistics of the .303 British Mk7 ammunition, that would enable me to zero for long ranges at 25yards or 100 yards. I know there is a Lee Enfield 25 yards zeroing target out there somewhere but I don't know how to get hold of it. Anyone? Bueller? Bueller?

[Josh Smith]

Hello,

100yds, zero at 50yds.

200yds, zero at 22yds.

300yds, zero at 14yds.

400yds, zero at 10yds.

500yds, zero at 7yds.

Hope this helps. I assumed a BC of 0.377 and 1000ft above sea level.

Josh

[eighteenninetytwo]

Thank you. But can you translate this into POI above a zero at 25 yards. I only have access to 25 yard or 100 yard range.

[Josh Smith]

Oh, I see what you're doing. I'm sorry.

100yds = 25yds -0.2"

150yds = 25yds +0.2"

200yds = 25yds + 0.6"

250yds = 25yds + 1.1"

300yds = 25yds + 1.6"

350yds = 25yds + 2.1"

400yds = 25yds + 2.7"

450yds = 25yds + 3.4"

500yds = 25yds + 4.0"

Is this what you needed, or do you need more, like the 100yd zeroes as well?

Thanks,

Josh

[emcon5]

How did you come up with those numbers? What did you use for a sight height?

[eighteenninetytwo]

That is perfect Thank you. Confirming that this is for .303 British Mk7 ammo yes? Did you work this out yourself or is this something you found elsewhere? And I don't suppose you have a figure for 800 yards do you?

[emcon5]

You can run the numbers yourself here:

http://www.jbmballistics.com/ballistics/calculators/calculators.shtml

Just set the Range Increment to 25 and the zero wherever you want it.

You need the Ballistic Coefficient (provided by Josh above) and the muzzle velocity (2440 fps if I remember correctly).

The most important number you will enter though, is sight height (The height of the sight (or scope) above or below from the centerline of the barrel). Make sure you have an accurate measurement, or the numbers you get will be wrong.

[semperfidelis354]

Oh, I see what you're doing. I'm sorry.

100yds = 25yds -0.2"

150yds = 25yds +0.2"

200yds = 25yds + 0.6"

250yds = 25yds + 1.1"

300yds = 25yds + 1.6"

350yds = 25yds + 2.1"

400yds = 25yds + 2.7"

450yds = 25yds + 3.4"

500yds = 25yds + 4.0"

Is this what you needed, or do you need more, like the 100yd zeroes as well?

Thanks,

Josh

I'm confused as to what this pertains to, I dont want to thread jack I just was wondering if someone could explain in barney style what I'm looking at?

[furyous68]

I believe:

Example: 500yds = 25yds + 4.0"

If you want to be dead center @ 500yds... then you need to adjust your scope so that when you aim @ the bulls eye of a target 25yds away, the bullet impacts 4" above the bulls-eye. This way, when you aim at your target 500yds away, the bullet impacts where you want it.

[emcon5]

I'm confused as to what this pertains to, I dont want to thread jack I just was wondering if someone could explain in barney style what I'm looking at?

The first number is the desired zero range. the last number is the point of impact at 25 yards.

So in theory, if you want to hit point of aim at 300yds but only have access to a 25 yard range, using those numbers you should adjust the sights so the rifle shoots 1.6" high at 25.

The problem is at such a short range, the changes are really small, and they are amplified as the range increases.

But without knowing the height of the sights on the OP's rifle, and the height Josh used, we are just guessing.

[semperfidelis354]

ahhhh I get it now thx

[Josh Smith]

How did you come up with those numbers? What did you use for a sight height?

Hello,

I think I used 1" because I couldn't remember for sure what it was. Shouldn't be too far off if it's a bit shorter.

Josh

[Josh Smith]

That is perfect Thank you. Confirming that this is for .303 British Mk7 ammo yes? Did you work this out yourself or is this something you found elsewhere? And I don't suppose you have a figure for 800 yards do you?

Hello,

For 800yds, try

25yds +10"

Check at 100yds +39.3".

Hope this helps!

Josh

[eighteenninetytwo]

Good man thank you.