What, please, is this? Yes I know it's a backsight, but off what?
Attachment 21241
OK, this is not a Bren part, but the people who know what this is are maybe more likely to be found here than on the rifle forums.
As a true packrat, I picked this up some time ago for no better reason than that I was intrigued by the mechanism.
I am not sure, but I think it might be from a Browning machine gun, or something similar. The frame is marked on the left side with M2 & '06.AMM
Attachment 21239
M2 machine gun???
AMM = Ammunition??
but what does '06. signify?
The slider is the astonishing part of the construction.
Attachment 21240
As you move the slider up the scale, it shifts to the left.
Attachment 21238
A very complicated solution, as the more obvious answer would have been to mill a normal parallel-sided frame and skew the whole assembly (like the Buffington sight on a trapdoor). The skew angle, by the way, is much more than I have seen on any rifle, and the length of the scale indicates a trajectory that has much more curvature than, for example, a 30-06 rifle bullet.
The sight is missing a long threaded rod and an knurled knob in the slit at the top, to provide screw adjustment similar to the Enfield No. 4 sight. The rod must have been something like a 4-48 thread - if anyone has the exact thread dimension, I would like to know so that I can cut a new one.
The knurled knob on the right is to clamp the slider. It is spring-loaded so that you can unscrew it and push it in to detach the nut section from the threaded rod, for rapid adjustment. Without this feature, you would need a couple of minutes to go from 100 yards to 2600.
The scale, from 100 to 2600 yards, has 25-yd intermediate markings, with an adjustable pointer setting (left and right of the slider). Again, this seems to be a touch of engineering overkill, as you would need an artillery rangefinder to determine 2600 yards to a precision of 25 yards. (I guess this sight was made long before the days of laser rangefinders).
Finally, please note the large hole marked A-A FIRE. There are fine lines at the side so that you can set this to a precision of 25 yards as well - if the aircraft is so co-operative as to stand still in the air while you measure the range.
All in all, a very interesting device. Which is why I bought it, following the packrat's motto "You never know, it might come in handy one day".
What do you think lads - would it look good on a Long-Range Sharps?
(Sorry, don't all scream at once!)
Patrick
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