Front post vs rear notch size?

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porkchop
Posts: 96
Joined: Sat Mar 23, 2019 3:34 pm

Re: Front post vs rear notch size?

Post by porkchop »

I have a question about David M's post, in those pictures does your eye seem to favor the lower left picture? Mine do, and I think it has to do with the shallower depth of the rear sight cut. It just seems easier to acquire or is this tricking my eye and mean nothing?
Stan
masaki
Posts: 35
Joined: Sun Jul 13, 2008 9:10 am
Location: Tokyo, Japan

Re: Front post vs rear notch size?

Post by masaki »

a supplement to my last(jan 25, 2022) post:

In my last post, I showed you two principle equations and mentioned that sight widths of my gun are not equal to the calculated values. They differ 5% or less. Most dominant causes of the differences between the calculated value and the actual values, which are obtained by actually seeing the sights and the target by my eye, are 0)error in measuring distance from the eye and 1)error caused by visual illusions which cut in brain's processes to obtain visual image(aka perceived image) out of the image projected on the retina.
Diameter of human eyeball is approximately 25mm. An accurate distance from the eye shall be measured from a point(optical center of the lens) that is somewhere between the retina and the aqueous humor, but never exactly center of the lens. Suppose, if you measure the distance from the lens, the maximum expected error in the distance must be less than 22mm. If you wear a shooting glass and it's distance from a point on the cornea of your eye is 20mm, maximum expected error in the distance must be a sum of the 22mm and the 20mm, which is 42mm, regardless of the dioptor of the shooting glass. If the shooter has an arm and shoulder lengths of average human adults, the errors in WF and WR are less than 5%.
Magnitude of visual illusions vary among individuals, but you can see how they are by your self.

My Walther LP500 came with a standard turnable front post. It is a triangle pole which has 3.8, 4.4 and 4.7mm faces. An optional larger one has 4.0, 4.5 and 4.9mm faces, which is better for me than the standard. I did not rush to purchase the larger one, because 4.9mm is still too small. I cut a 2.0mm-thick Aluminum plate into a shape which has a 5.4mm-width face and painted in matte black as shown in the photos below.
5.4mmPost.jpg
5.4mmPost.jpg (37.45 KiB) Viewed 960 times
5.4mmPost0.jpg
ciao!
masaki
Posts: 35
Joined: Sun Jul 13, 2008 9:10 am
Location: Tokyo, Japan

Re: Front post vs rear notch size?

Post by masaki »

a web calculator is available at
https://tachrifle.sakura.ne.jp/data/cal ... dths3.html

masaki
Tokyo, Japan
Rover
Posts: 6983
Joined: Sat Nov 15, 2008 4:20 pm
Location: Idaho panhandle

Re: Front post vs rear notch size?

Post by Rover »

Not quite the same as any of the above, but:

I have an old Mauser military rifle that has a triangular front sight that shoots very high (the ol' aim for the belt buckle philosophy).

I merely snipped the tip off a Zip-tie of appropriate width and height and super-glued it on to the front sight. Amazingly, it was perfect!

This shit ain't rocket science, guys! Mess around a little!
BobGee
Posts: 579
Joined: Fri Oct 01, 2010 6:43 am
Location: Sydney, Australia

Re: Front post vs rear notch size?

Post by BobGee »

+1 for Dina. Just learn to lock your wrist and then you don't need to bother with these side bar widths.

Bob
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