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Post by brokennock on Jan 13, 2021 6:01:10 GMT -7
I need some help from the math and engineering guys.
All else being equal,hypothetically, if one's gun is sighted in at, say 50 yards, and one moves one's rear sight 6" back toward the breach plug, does this change the point of impact?
If so, up or down?
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Post by paranger on Jan 13, 2021 7:06:37 GMT -7
If the front and rear sights are EXACTLY the same height in your preferred sight picture (which I think pretty unlikely), then a change in sight radius should theoretically have no effect on point of impact. However, if there is any difference between the two sights in height above bore, changing the sight radius will change point of impact. Without precisely knowing that difference, it is impossible to calculate the effect.
If the rear sight is higher than the front, for example (as I suspect is the case), then increasing sight radius (with the same sight picture) will lower point of impact.
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Post by brokennock on Jan 13, 2021 7:20:29 GMT -7
Thank you.
Would the inverse be true? If the rear sight is shorter than the front will increasing radius raise point of impact?
On actually not moving the sight, I'm adding one. But looking for a starting place in comparison to my other 20 gauge smoothbore that already has one in basically the standard rifle position. I am putting a small brass rear sight, removed from an old gun, on my Fusil des Chase but am placing it about even with the front lock bolt. I plan to compare sight measurements so I have an expectation of point of impact before I start wasting lead and powder.
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Post by paranger on Jan 13, 2021 7:33:52 GMT -7
Gotcha. Yes, the inverse would also be true.
Keep in mind that your sight picture can have a significant effect. For instance, assuming your sight heights are exactly equal (top of notch in rear sight is same height as top of blade on front sight), if you like to "bury" your front sight bead in the notch, you are effectively inducing the same effect as having a higher rear sight.
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coot
City-dweller
Posts: 152
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Post by coot on Jan 13, 2021 12:20:24 GMT -7
If the barrel is swamped or tapered, moving the rear sight back (onto a thicker area) will have the effect of raising the rear sight relative to the center of the bore. Depending on how far back and how much raise in sight, there could be no effect or the poi could rise or decrease. It is all a matter of geometry. Why are you moving the sight back? Most times it gets moved forward (due to older eyes not focusing up close or in the case of one of my rifles, because the sight was installed right at the balance point & thus a pain to carry).
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Post by brokennock on Jan 13, 2021 14:40:54 GMT -7
If the barrel is swamped or tapered, moving the rear sight back (onto a thicker area) will have the effect of raising the rear sight relative to the center of the bore. Depending on how far back and how much raise in sight, there could be no effect or the poi could rise or decrease. It is all a matter of geometry. Why are you moving the sight back? Most times it gets moved forward (due to older eyes not focusing up close or in the case of one of my rifles, because the sight was installed right at the balance point & thus a pain to carry). I am a very "front sight focused," shooter. As a combative pistol instructor in the modern world for quite some time, I am used to my rear sight being blurry, or barely noticed at all. Almost a subconscious reference. I want it back where I can pretty much ignore it when using shot, and its position though blurry focuses me in the front sight. I have it stuck in place with fletching tape now and am shouldering the gun often. Seems to be in the right place for what I want. Also, it is out of the way if the balance point when carrying. My smoothrifle rear sight is right where I want to wrap my hand around it while walking, very annoying. |
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coot
City-dweller
Posts: 152
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Post by coot on Jan 13, 2021 15:17:16 GMT -7
I know what you mean re the discomfort of having the rear sight at the balance point - where it will dig into one's hand. I had to have it moved on one of my rifles for that very reason. It almost seems a design defect - why not locate the rear sight after the gun is finished enough to determine the balance point.
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Post by artificer on Jan 15, 2021 17:41:51 GMT -7
I need some help from the math and engineering guys. All else being equal,hypothetically, if one's gun is sighted in at, say 50 yards, and one moves one's rear sight 6" back toward the breach plug, does this change the point of impact? If so, up or down? Hi Nock, Don't be surprised if moving the rear sight 6" back ALSO changes the windage. The first cause can be mechanical, I.E. if the rear sight is not in the same relative position as it was before you moved it. The second cause is as you increase sight radius (the distance between the sights) there is LESS human error in using the sights. Bullseye and Centerfire Pistol shooters are very aware of this because if the wrong type of sights are used with each other, the pistol sight radius might increase just beyond the maximum allowable distance. Gus |
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Post by brokennock on Jan 19, 2021 15:25:28 GMT -7
Any thoughts on attaching this semipermanent rear sight? I have heard of folks using epoxy, somehow that doesn't sit well with me. I'm thinking of using the same low temp solder paste I've used for reattaching broken off barrel lugs.
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Post by hawkeyes on Jan 20, 2021 9:29:27 GMT -7
Any thoughts on attaching this semipermanent rear sight? I have heard of folks using epoxy, somehow that doesn't sit well with me. I'm thinking of using the same low temp solder paste I've used for reattaching broken off barrel lugs. Without a dovetail, solder. |
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