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Model 1868/70 rear sights (long)
Posted by Dick Hosmer on Wednesday, 22 October 2014, at 2:44 a.m.
I am preparing a "Trapdoor News" article on Model 1868 rifle #62, and, as part of the background work have measured the rear sights of the 13 different full length arms originally equipped with the 1868/70 sight. Carbines were ignored for the purposes of this exercise. Nearly all of the sights inspected had the U-slit as opposed to the "V" sighting notches, on both the fixed leaf and slide. #62 has "V"/"V", as does my 1869 Cadets. My 1870 Trials rolling block has a "V" leaf and a "U" slide, while my Type 2 Springfield/Sharps has a "U" leaf but a "V" slide. With the exception of the slide on #62, which I restored, nothing is known of the others - but surely such items had to be repaired from time to time, and it is unlikely that ALL such replacements followed currently understood collector protocol.
Sight radius (measured from rear face of notch on leaf hinge (with leaf down) to rear face of bayonet stud) varies from a minimum of 25" on the 1869 Cadets to a maximum of 29.125" on the Ward-Burton rifle. It could be said that there are two distinct "groups" (3 "short" and 10 "long"). Sight radius for the 3 shorter barrels averages 25.3"; for the 10 longer ones it averages 28.6", a difference of 3.3", which might be significant with finer sights.
For any number of reasons (including the caliper operator's eyesight) there are variances in the sights measured, but no clear pattern emerged to indicate that sight radius (or barrel length) was any sort of determining factor in the location of the graduations, since the individual measurements for the "short" and "long" barrels do NOT cluster at opposite ends of the data spread, as might have been expected.
None of the sights inspected have a line at the "2". I t would seem that digit is simply intended to relate to the notch in the bottom of the window. The location of the digit does vary slightly from sight to sight.
All of the sights inspected, save that for #62, have a line for the "9", which in most cases, is basically coincidental with the top edge of the window. On those sights where it does not hit the window edge it is below it - the line never runs clear across, above the window.
The only clear difference appears to be that the sight on #62 IS graduated differently for 500yds. and above than all of the other sights, as those three readings are definitely outside their respective ranges. However, the 200yd. and 300yd. indicators on the #62 sight fall well within the average spreads, and are thus unremarkable.
The 900yd. notch on #62 is 0.278" above the average, while the 700yd. and 500yd. lines are 0.107" and 0.108" higher on the leaf than their respective averages. These are signifcant differences, easily visible to the naked eye, when compared side-by-side.
I am therefore proposing that the rear sight found on #62 is indeed an early variant, possibly unique, at least unrecorded to date, which somehow escaped replacement over the years.
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