Shooting with metric open sights

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BJung

New member
My question is how do I adjust my POI using metric sights.

I will be shooting an Arisaka this Friday. My reloads POI is known given my ladder test. Some are just at the Point of Aim at 100 yards. I plan to use the 200 and 300 yards settings. How much higher should I estimate the actual POI be at 200 and 300 yards so I don't overshoot my target? The target is 30"x30"?
 
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T. O'Heir

New member
I think which model you have matters.
Apparently, a 7.7 Type 99 has a set 300 meter battle sight with no windage adjustment(that'd be done with the front I think). Rumour has it a 6 o'clock hold gives a POI about 4" above the bull. No mention of what target. And it sounds decidedly speculative.
https://thefiringline.com/forums/archive/index.php?t-580259.html
"...estimate the actual POI..." There is no estimating involved. POI means Point Of Impact. That's wherever the shot hits.
 
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Jim Watson

New member
I doubt the difference between a yard and a meter will be noticeable with an army surplus rifle shooting reloaded ammo. It might be up, it might be down.
 
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T. O'Heir

New member
"...Meter is 10% longer than a yard..." A meter is 3" longer than a yard. 39" vs 36". And it's 328.25 yards. Like Jim says, it makes no difference.
 
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jrothWA

New member
You'll have to re-fire at 100 yds and see....

the change is for impact and extrapolate out the come-ups for 200 & 300.

The adjust during the match.

What is your reload, I have a buddy with a 99 but trying to get him to the range is PULLING TEETH!
 
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44 AMP

Staff
1 meter = 39.37 inches.

So, yes, its about 10%. Does this make a difference?
Sometimes, yes, sometimes, not so much. And, when it is yes, is it enough you can see, use, or compensate for??

What load are you going to be shooting in your Arisaka? Makes a wee bit of difference.

You need to know the approximate velocity and bullet type, and look in the drop tables. Using a drop table for your specific bullet is more precise, but a general idea can be had for all bullets of the general caliber weight, type and speed.

I looked in one of my old Hornady books, and it shows two bullets for the 7.7Jap, a 150 spire point and a 174gr RN.

At the listed max speed of 2700fps, from a 100 yd zero, the 150gr drops 4.3" at 200 yds and 15.9" at 300 yards.

The 174ger RN at its listed max speed of 2400fps drops 6.8" at 200 and 24.6" at 300 from a 100yd zero.

So, if you're shooting a 150 at top speed, you're going to be close to a foot and half LOW at 300, and if you're shooting a 174 (equivalent of Jap military ammo - which is what the sights would have been calibrated for) you're going to be about 2 FEET LOW at 300 when sighted dead on at 100.

The Arisaka sights not match type sights. They are "battle sights" and I believe set for 300M at their lowest setting.

Most European nations zeroed their infantry rifles at 300 meters and I believe the Japanese did also.
 
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Jim Watson

New member
you're going to be about 2 FEET LOW at 300 when sighted dead on at 100.
Click to expand...

Which is why you should not zero at 100 if there is any chance you will shoot at much longer range.

On the other hand:
Tim Mullin in 'Shooting the War Weapons' said that "There are untold people now alive because their grandfathers were shot over by rifles that would not zero closer than 400 yards."
 
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44 AMP

Staff
"There are untold people now alive because their grandfathers were shot over by rifles that would not zero closer than 400 yards."
Click to expand...

And there are untold numbers of people who never were alive because their grandfathers were shot by guys who zeroed their rifles at 3 or 400meters AND remembered their training to aim for the other guy's belt buckle...

Seriously, it was a thing with some (most?) European armies, to tell their troops to aim at the enemy's belt buckle. This allowed for a torso hit (somewhere) if the range estimation was a bit off.
 
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BJung

New member
I went to the range to shoot test loads. Most were unsatisfactory. The best performing load was a 7.7-174gr FMJBT loaded with 45.3gr R15 ( initial test was 41.7gr - 45.9gr R15 ). COAL was the longest I could assemble the cartridge where it could fit in the magazine. Using the battle sights, I centered a 2" circle in the aperture and the front sight was just under the left the dot. A 3/4" group was 1" high and 1" to the left. I flipped the ladder sights up thinking that the lowest sight was a battle sight. I discovered that this was a 200m sight and did not use it. Using the 300m sight and centering the aperture to a 6" red paper plate, a 2" group was printed high and left by 4" at 200 yards. I hit my target once on the left edge at 300yards using the 300m sights and using a 10" paper plate to center in the aperture. That bullet was 12" left of the bullseye. When I return to the range, I plan to shoot 12" right of the target and see how much my spread is. Unlike this test load, I hope to use my custom lee collet neck sizing die. My hope is to place a group in that 10" plate.
 
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jrothWA

New member
Thanks for response.

Just asissted my friend with loading 24 case, with 4064, Hornady 174gr matchpoints, 200CCI. three loads: no IDing them untill chronographing is done.
 
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OldManMontgomery

New member
Coments by Jim Watson and 44 AMP: The 'shooting at belt buckle" is correct but for a specific reason. The reason is that is the idea of the 'battle sight zero', or what is known as 'point blank'.

Using this concept any battle rifle has - depending on trajectory, which is determined by the governing agency's decision and not dependent on troops - will have a trajectory rise and fall of so much (depending on velocity). The idea is to calculate from the trajectory and testing at what ranges the rifle ammunition will impact within a rectangle the perceived size of an enemy's torso. Usually this begins just beyond the barrel and reaches out xxx yards, meter, arshins, schritte, (or whatever). This is the distance where the strike of the bullet will not rise more than the vertical height of that rectangle. At a given point the trajectory will then arc down and the rifleman is instructed to aim at shoulder height so the falling arc of trajectory will strike the torso for a ways more. But no sight adjustments are required.
Therefore, a 400 yard (etc.) battle sight will hit that area out to 400 yards within the conditions explained. It is NOT and was never a pinpoint zero for a target at precisely 400 yards.

The current hunter can use the same principle, but consider a five or six inch circle and figure the same trajectory requirements. Probably most do without realizing.
I learned this concept of battle sight zero in Marine Corps basic training in 1969. Most forgot about it instantly. I was a nerd and seized upon it.
 
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Jim Watson

New member
The 1903 Springfield battle sight - the notch visible with the "ladder" folded down - is said to be 547 yards (Which I eventually realized was 500 meters.)

The Marine sights with a single aperture in the drift slide and a taller, wider front blade shifted the battle sight to about 300 yards, which makes a lot more sense with open sights.
 
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