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Front Sight Blade Height, Zero (Read 3774 times)
Stretch32
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Front Sight Blade Height, Zero
Sep 19th, 2016 at 8:40pm
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I just picked up my first Krag last week (an M1892 rifle made in 1894) and had a quick question regarding front sight blade heights. The rifle in question has a sporterized stock but retains it's full length barrel and has been updated to M1896 standards with an M1896 rear sight. It had an after market small front sight blade on it that was shorter than  the .283 1896 front sight blade that should be on it so I made a .413 high sight blade to replace it. My understanding is that an M1896 sight arrangement was zeroed at 300 yards so I figured the taller M1898 front sight blade would bring the zero down to the 200-250 yards that I'm looking for.

I took it out shooting this weekend and at 50 yards the rifle printed 6.5" high (but centered for windage). I then shot out to 200 yards and it ended up shooting about 3-5 feet short. I ramped the sight to about the 500 yard and it would then hit a steel torso sized target at that range.

I was shooting Remington and Winchester commercial ammo and both types of rounds achieved the same results.

What height front sight blade would I need to zero an M1896 rear sight to 200 yards (with the ramp full down)? I plan to shoot a 220 grain projectile with 40 grains of H4350 to replicate the original spec Krag cartridge.

Any thoughts would be appreciated.

Stretch
  
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Parashooter
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Re: Front Sight Blade Height, Zero
Reply #1 - Sep 19th, 2016 at 9:58pm
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Pretty much depends on your eyesight, sight picture, target dimensions and ammunition. No two people, rifles, or cartridges are exactly the same.

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Once you've established the existing point of impact under your conditions, it's easy enough to calculate the required change using a little elementary trigonometry:
Sight radius times the tangent of the angular POI change required equals sight height change. (Tangent of 1 MOA is 0.000291.)
  
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Stretch32
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Re: Front Sight Blade Height, Zero
Reply #2 - Sep 20th, 2016 at 12:07am
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I would like to see / shoot like Willi ie: "Dot the I".

Assuming (never good I know) that an M1896 rifle is zeroed at 300 yards for this sight picture (with USGI ammo), what height would the front sight blade need to be to achieve this picture / zero at 200 yards?

At this point I can make all the front sight blades I need in any size. I would like to at least find a point to deviate from to get started.

Thanks again.

Stretch
  
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Parashooter
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Kragmudgeon

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Re: Front Sight Blade Height, Zero
Reply #3 - Sep 20th, 2016 at 5:11am
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With a 6:00 hold, that would depend on the size of your aiming bull - which dictates how far the center is from the POA. A group in the center of a 10" bull isn't the same distance from POA as one centered in a 20" bull.

What you have to do first is find your POI with a specified distance, POA, and bull size. Then you can calculate sight height to zero at another distance and/or bull while employing the same perceived sight picture.
  
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Stretch32
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Re: Front Sight Blade Height, Zero
Reply #4 - Sep 22nd, 2016 at 6:12pm
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Sounds good.

I'm going to load up some 30-40 rounds this weekend to the specs I mentioned above and see how it goes. From there I'll compute the front blade height required to hit a 100 yard rifle target (12" diameter I think) in the center at 200 yards.

With that, does anybody have a spare repro or original .286 rifle front sight blade for an M1896 sight arrangement they'd like to sell? I'd like to toss it in the spares box just so I have one for my rifle.

Stretch
« Last Edit: Sep 25th, 2016 at 4:42am by Stretch32 »  
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Mark_Daiute
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Re: Front Sight Blade Height, Zero
Reply #5 - Sep 26th, 2016 at 12:45am
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put the proper front sight on it, shoot cast and raise the leaf to get on for the desired distance.

I'm shooting an 1896 with the 1896 rear sight. Bullet 311284 with 50 grains of WC872 is on at 200 yards. Load matches the sights.


Same bullet with 16 grains of 4759, I use 400 yard dope to be on at 200 yards, 200 yard dope to be on at 100 yards.
  
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