Sharpe's The Rifle in America -- Optics Text

[Pareto]

I recently acquired a mint copy of the 1995 hardback reproduction of Sharpe's The Rifle in America. And it is a beautiful edition that preserves a lot of information about the history of American arms.

But I was struck by some bad advice in various places, most egregious of which was this passage (from p. 331)

"Suppose one is shooing on a 75-foot range. One carefully aimed "sighting shot" shows an 8 o'clock bullet hole in the target one-half inch low and an inch to the left of the center of the bullseye. To correct for this and bring the succeeding shot into the center of the bullseye, the elevation screw is given two clicks to the left so as to raise the sights two minutes of angle and the windage screw is given four clicks to the left for four minutes of angle. The next shot is centered."

What?? He then goes on to explain correctly that one MOA is approximately one inch at a 100 yards. Am I missing something here?

 

[dellet]

75 feet/25 yards 1/4” = 1 MOA.
Sounds like his math is right but he needs either a scope or mounts with a finer adjustment.

 

[Bladesmith]

75 feet/25 yards 1/4” = 1 MOA.
Sounds like his math is right but he needs either a scope or mounts with a finer adjustment.

I initially read the OP as 75yds, so I was wondering myself lol

 

[Dave M.]

Assuming his scope is adjusting at 1/2” per click at 100 yards (very rough adjustment), at 75 feet which is 25 yards (or 1/4 of the 100 yards) each click would move his point of impact (1/2)/4=0.125” therefore he’d need 4 clicks of elevation in the upward direction, and double that or 8 clicks of windage adjustment to the right.
The only way his math would make sense is if each click represented approx 1” at 100 yards, which I suppose they may have made open sights with such rough adjustments on an old rifle.
Dave

 

[ISS]

You need to view the book thru 1937 eyes. Scope technology to be precise. Unertl was the king, but you can make the adjustments based on three separate and distinct settings. External adjustment scopes have scope blocks that can be set at three lengths between front and rear that I am aware of. I have single shot rifles with the blocks set at 7.2", 11.4", and 14.4" spacing. Each setting moves POI a different amount at 100 yards. 7.2" = 1 inch per click. 11.4 = 1/2" per click, and the 14.2 = 1/4". Note that14.2" is twice the 7.2" spacing.
I own about half a dozen of the big Unertls. Two measure 15 1/2" and 16.5" long. A third is 25 1/2" long.
I own a Zischang barreled Stevens 44 1/2 Schuetzen rifle in 32-40. The blocks are the 7.2" apart spacing. Schuetzen centerfire matches are a 2" bull (iirc) at 200 yards.
For more information on the scopes of "little Phil Sharpe"* as Elmer Keith referred to him see Dewey Greiner's website.

ISS

* Elmer Keith was 2" taller than Sharpe. The two were in competition for articles in the only real gun magazine at the time. The American Rifleman.

 

[Wild Bill IV]

I recently acquired a mint copy of the 1995 hardback reproduction of Sharpe's The Rifle in America. And it is a beautiful edition that preserves a lot of information about the history of American arms.

But I was struck by some bad advice in various places, most egregious of which was this passage (from p. 331)

"Suppose one is shooing on a 75-foot range. One carefully aimed "sighting shot" shows an 8 o'clock bullet hole in the target one-half inch low and an inch to the left of the center of the bullseye. To correct for this and bring the succeeding shot into the center of the bullseye, the elevation screw is given two clicks to the left so as to raise the sights two minutes of angle and the windage screw is given four clicks to the left for four minutes of angle. The next shot is centered."

What?? He then goes on to explain correctly that one MOA is approximately one inch at a 100 yards. Am I missing something here?

A low hit of 1/2" at 75ft (25YARDS) translates to 2" at 100yds! Since the micrometer rear sights are 1 MOA adjustments, 2 clicks up!! HE IS RIGHT!!!

For the 1" left of target at 75ft (25YARD), which translates to 4" at 100yds, the adjustment would be 4 click RIGHT NOT LEFT!!!

TRUE MOA = (π÷3)" @ 100yds in the irrational form!!!

 

[dellet]

A low hit of 1/2" at 75ft (25YARDS) translates to 2" at 100yds! Since the micrometer rear sights are 1 MOA adjustments, 2 clicks up!! HE IS RIGHT!!!

For the 1" left of target at 75ft (25YARD), which translates to 4" at 100yds, the adjustment would be 4 click RIGHT NOT LEFT!!!

TRUE MOA = (π÷3)" @ 100yds in the irrational form!!!

As said earlier based on the publishing date. Likely an externality adjusted scope. If it is one at all. Note that the reference is to an “elevation screw”.

The tricky part is the windage, the only time a rear sight will move bullet impact to the right while turning the adjustment screw to the left, counter clockwise, would be either reverse threads on a sight, or backing out the wndage dial of an externally adjusted scope allowing the rear of the scope to move to the right.

An elevation screw turned left, counter clockwise, raises the rear of the scope, bullet impact goes up.

 

[Wild Bill IV]

As said earlier based on the publishing date. Likely an externality adjusted scope. If it is one at all. Note that the reference is to an “elevation screw”.

The tricky part is the windage, the only time a rear sight will move bullet impact to the right while turning the adjustment screw to the left, counter clockwise, would be either reverse threads on a sight, or backing out the wndage dial of an externally adjusted scope allowing the rear of the scope to move to the right.

An elevation screw turned left, counter clockwise, raises the rear of the scope, bullet impact goes

First of all, these old vintage scopes pivoted on the Objective mount (the mount closest to the object or target) and were adjusted at the Ocular mount (closest to the eye)!! The reticle was fixed in the scope tube!! By the way, the first reticles were hair in the first scopes made and later changed to fine wire!!!! Thus the phrase IN THE CROSS HAIRS!!!

The scope tube axis, cross hairs, in this example are set too high and right for POI (point of impact). There fore the elevation needs dropped to put the horizontal hair on the POI or the ocular end of the scope needs raised!! Turning the elevation left (counter clockwise) pulls the ocular lens up (dropping the objective lens end) and reduces the angle of bore axis to scope tube axis! Thus, the horizon hair is now on the same plane of POI!! LEFT HAND THREAD ON ELEVATION!

To align the WINDAGE, vertical hair, the ocular end needs to be pulled right for the scope tube axis to shift to the left and align the tube axis with the barrel axis (since the POI was left). The dial graduations both progress, increase in value, in the same rotation (Left or CC increases the graduations in respect to the index mark)! Thus turning the dial left (CC) pulls the ocular end of the scope to the right and the vertical hair is now in the same plane of the POI!! LEFT HAND THREAD ON WINDAGE!!!

Another example of days long gone!!!
In the days of cannons firing cannon balls, the cannon balls were stored in a rack made of brass. This rack was called a monkey!!! When the weather turned really cold, the brass rack would contract spilling the cannon balls!!

Thus, we get the very old phrase:
COLD ENOUGH TO FREEZE THE BALLS OFF A BRASS MONKEY!!!!

 

[dellet]

First of all, these old vintage scopes pivoted on the Objective mount (the mount closest to the object or target) and were adjusted at the Ocular mount (closest to the eye)!! The reticle was fixed in the scope tube!! By the way, the first reticles were hair in the first scopes made and later changed to fine wire!!!! Thus the phrase IN THE CROSS HAIRS!!!

The scope tube axis, cross hairs, in this example are set too high and right for POI (point of impact). There fore the elevation needs dropped to put the horizontal hair on the POI or the ocular end of the scope needs raised!! Turning the elevation left (counter clockwise) pulls the ocular lens up (dropping the objective lens end) and reduces the angle of bore axis to scope tube axis! Thus, the horizon hair is know on the same plane of POI!! LEFT HAND THREAD ON ELEVATION!

To align the WINDAGE, vertical hair, the ocular end needs to be pulled right for the scope tube axis to shift to the left and align the tube axis with the barrel axis (since the POI was left). The dial graduations both progress, increase in value, in the same rotation (Left or CC increases the graduations in respect to the index mark)! Thus turning the dial left (CC) pulls the ocular end of the scope to the right and the vertical hair is now in the same plane of the POI!! LEFT HAND THREAD ON WINDAGE!!!

With right hands threads; righty tightly, lefty loosey.

External mounts do not pull, they either push into spring tension or release from it.

Right hand threaded knobs mounted on the right side of the scope will push the scope and cross hairs to the left turning the knob to the right, clockwise. Basically you are threading a screw through the mount, pushing the scope away. Turning the screw to the left withdraws the screw and allows the spring on the opposite side to push the scope to the right.

If the adjustment screw passed through the scope, or a rear sight, the screw would be fixed and the sight would slide. With right handed threads turning the adjustment to the right pulls the sight to the right. Pushes to the left. Unless I’m totally asleep bullet follows direction of sight movements on the rear.

So for Phil Sharpe to turn the adjustment screws to the left and move the bullet both up and right, it was either an externally adjusted scope, or an iron sight with left handed threads.

 

[Wild Bill IV]

With right hands threads; righty tightly, lefty loosey.

External mounts do not pull, they either push into spring tension or release from it.

Right hand threaded knobs mounted on the right side of the scope will push the scope and cross hairs to the left turning the knob to the right, clockwise. Basically you are threading a screw through the mount, pushing the scope away. Turning the screw to the left withdraws the screw and allows the spring on the opposite side to push the scope to the right.

If the adjustment screw passed through the scope, or a rear sight, the screw would be fixed and the sight would slide. With right handed threads turning the adjustment to the right pulls the sight to the right. Pushes to the left. Unless I’m totally asleep bullet follows direction of sight movements on the rear.

So for Phil Sharpe to turn the adjustment screws to the left and move the bullet both up and right, it was either an externally adjusted scope, or an iron sight with left handed threads.

So both threads would be right handed on the vintage scopes that used spring tension!!

Elevation, left turned, loosey, spring pushes the ocular up, dropping the vertical hair on the POI!!
Windage, left turned, loosey, spring pushes the ocular right, swing the vertical hair to the left and aligning with POI!!!

Looking at it from having studied OPTICS in physics, the reticle is located close to, if not on, the objective lens beyond the objective pivot point mount. Think about a titer-toter, or better yet, a lever, where one end goes up, and the other end drops!! The reticle can not be at the pivot point because the cross hairs wouldn't move no matter the adjustments! This would allow fine threads (Ultra fine in modern scopes) to have minute changes since the fulcrum (pivot) point would be longer on the ocular side and short at the objective!!!

Now, his second shot could hit the target dead on at 75 ft since the barrel will now be point 1/2 higher and 1" right from the 1st shoot at that range!! He now has a lot better POI!!!

Does this logic work for you now!!!!

 

[dellet]

So both threads would be right handed on the vintage scopes that used spring tension!!

Elevation, left turned, loosey, spring pushes the ocular up, dropping the vertical hair on the POI!!
Windage, left turned, loosey, spring pushes the ocular right, swing the vertical hair to the left and aligning with POI!!!

As long as it makes sense to you. I shoot these types of scopes regularly. So have a reasonable handle on it.
It can be confusing switching between a vernier type Soule sight, externally adjusted scopes with Unerl style mounts, Malcolm style external mounts that are vernier style, external adjustment scopes, some with front and rear adjustments, windage and elevation adjustable front sights and modern scopes.
Then add in changing “click” values for different barrel lengths(sight radius) or distance between scope mount variations.
I can get confused at times.

Not that it matters in the long run, but on these externally adjusted scopes, the reticle is at the rear, just in front of the ocular lens. Most are adjustable. Since these scopes slide freely in the mounts holding vertical was accomplished with a locator of some type on the tube. most often a rib. The cell enclosing the cross hairs could be rotated to true vertical/horizontal.

So back to my original post. The description as laid out in the book is correct. The only thing that can be questioned would be the click value.

 

[Wild Bill IV]

As long as it makes sense to you. I shoot these types of scopes regularly. So have a reasonable handle on it.
It can be confusing switching between a vernier type Soule sight, externally adjusted scopes with Unerl style mounts, Malcolm style external mounts that are vernier style, external adjustment scopes, some with front and rear adjustments, windage and elevation adjustable front sights and modern scopes.
Then add in changing “click” values for different barrel lengths(sight radius) or distance between scope mount variations.
I can get confused at times.

Not that it matters in the long run, but on these externally adjusted scopes, the reticle is at the rear, just in front of the ocular lens. Most are adjustable. Since these scopes slide freely in the mounts holding vertical was accomplished with a locator of some type on the tube. most often a rib. The cell enclosing the cross hairs could be rotated to true vertical/horizontal.

So back to my original post. The description as laid out in the book is correct. The only thing that can be questioned would be the click value.

The click value is 1MOA (~1" at 100 yards) on your OP!! TRUE MOA=(π÷3)@100 yards (irrational form, not numeric)!! Go back to my earlier post where I translated the angle, related cone, from 75 feet, to 100 yards. So at 25 yards, (100 yards/4) 1/4"/click change. At 50yds ((100/2) is 1/2"/click!! At 100yds (1x100 yards), 1"/click. At 200 yards (2x100), 2"/click!!! At 300 (3x100), 3"/click!!!

I too shoot a couple of target rifles! One has the Lyman caliper rear sights!! The other is a Swedish caliper rears!! Both have front hooded sights with interchangeable inserts!! But the inserts are not interchangeable since one is American STD and the other is Metric!!!
I really true enjoy my Swedish CG-63!! A converted Swedish small ring Mauser (6.5x55) with tuned target trigger, Norma 29.5" Palma barrel, target rear caliper and front hood sight done at the factory that originally manufactured the Swedish Mausers!! Hitting 16" OD implement discs at 600yds, in the sitting, slung position is easy!!! Ring em all day long with cheap B&S factory Ammo!!!

 

[dellet]

The click value is 1MOA (~1" at 100 yards) on your OP!! TRUE MOA=(π÷3)@100 yards (irrational form, not numeric)!! Go back to my earlier post where I translated the angle, related cone, from 75 feet, to 100 yards. So at 25 yards, (100 yards/4) 1/4"/click change. At 100yds (1x100 yards), 1"/click. At 200 yards (2x100), 2"/click!!!

That’s not the point.
I have never seen a scope that had a true “click” adjustment knob that the value was one MOA. The most course I have ever personally seen is 1/2 MOA. Now a 1/2 MOA adjustment could certainly be a 1 MOA by decreasing the distance between mounts, so it is possible, not practical. There were plenty of non “click” adjustable mounts that the index marks were 1 MOA.

It’s more likely that due to the prominence of the writer, it was ease of explanation that one click, one MOA was written and not that the only thing he had to use was the cheapest scope on the market or one whose mounts were the latest and greatest thing at the 1875 shot show.

Bonus point if anyone knows where the 1875 shot show was held, I don’t think it was Las Vegas that year?

 

[Wild Bill IV]

That’s not the point.
I have never seen a scope that had a true “click” adjustment knob that the value was one MOA. The most course I have ever personally seen is 1/2 MOA. Now a 1/2 MOA adjustment could certainly be a 1 MOA by decreasing the distance between mounts, so it is possible, not practical. There were plenty of non “click” adjustable mounts that the index marks were 1 MOA.

It’s more likely that due to the prominence of the writer, it was ease of explanation that one click, one MOA was written and not that the only thing he had to use was the cheapest scope on the market or one whose mounts were the latest and greatest thing at the 1875 shot show.

Bonus point if anyone knows where the 1875 shot show was held, I don’t think it was Las Vegas that year?

It is the same angle 1" rise/click with 100yds run EQUALS 1/4" rise/click with 75ft (25yds) run! He stated 2 clicks elevation, 1/2" rise with 75ft(25yds) run OR 2"rise at 100yds run!! AND 4 click up 1" rise with 75ft(25yds)run or 4" rise with 100yds run!! That is 1MOA/CLICK!!!
It is associated with the trig!! Similar right triangles can be made with one common adjacent angle!! Used a lot in Analytical Geometry in Calculus and my field of study, Physics!!!

 

[dellet]

He stated 2 clicks up to adjust for 2" at 100 and 4 click to adjust for 4" at 100!! That is 1MOA/CLICK!!!

That’s not what was stated at all. But the math was correct.

Suppose one is shooing on a 75-foot range. One carefully aimed "sighting shot" shows an 8 o'clock bullet hole in the target one-half inch low and an inch to the left of the center of the bullseye. To correct for this and bring the succeeding shot into the center of the bullseye, the elevation screw is given two clicks to the left so as to raise the sights two minutes of angle and the windage screw is given four clicks to the left for four minutes of angle. The next shot is centered."

This is how I get confused.

 

[Wild Bill IV]

That’s not what was stated at all. But the math was correct.


This is how I get confused.

Let me draw a diagram!! Seeing it on paper will help!!! Give a little time, and when I post it, open the attached file!!!

 

[Wild Bill IV]

That’s not what was stated at all. But the math was correct.


This is how I get confused.

Here is the diagrams!! The angles on the drawing are not correct, but I need to show the relevance due to the huge drawing I would have to make to show the true angles, the rises, and the runs!! The angles in MOA and the clicks are on the right side!! The runs are below each similar triangle and the rise is inside the similar triangles!!

The top triangle is 1 MOA (0.01667°).
The middle triangle is the elevation adjustment of 2 MOA (0.03333°).
The bottom triangle is windage adjustment of 4 MOA (0.06667°).

 

[dellet]

Here is the diagrams!! The angles on the drawing are not correct, but I need to show the relevance due to the huge drawing I would have to make to show the true angles, the rises, and the runs!! The angles in MOA and the clicks are on the right side!! The runs are below each similar triangle and the rise is inside the similar triangles!!

The top triangle is 1 MOA (0.01667°).
The middle triangle is the elevation adjustment of 2 MOA (0.03333°).
The bottom triangle is windage adjustment of 4 MOA (0.06666°).

I’m honestly not sure what you’re trying to get me to understand.

What does all that math, and all those diagrams have to do with someone making a poor choice in a set of scope mounts?

 

[Wild Bill IV]

I’m honestly not sure what you’re trying to get me to understand.

What does all that math, and all those diagrams have to do with someone making a poor choice in a set of scope mounts?

This post has made a left turn!! I answered all relevant questions based on the OP and follow up questions!! This last question has no answer!!! I'm done chasing the rabbit!! Time to move onto other threads!!! What a waste of time!!!!

 

[snert]

Bill
I could follow everything but the exclamation points!!!!!!!!!!



Dellet,
I gotta chat with you. I just inherited a Unertle and have a Stevens 414 and a 40XBR as potential rifles. NO IDEA how to chose distance and mounts for those rifles.