Ross M10 rear sight disassembly?

[H Wally]

I've got an M10 or M1910 or MIII, whichever you prefer to call it, and it's got a jammed windage adjustment drum on the rear ladder sight. The sight's darn simple, yet I can't figure out how to disassemble and remove the drum for cleaning??? There's only one darn screw, but removal doesn't seem to solve anything. Only thing I can think of is that the rear aperture plate must slide all the way off the track and allow the drum to come out that way. Anyone know?

This style for reference

 

[Oldguncrank]

H/W
You should expend all efforts with release oil. heat, and perseverance first to free the windage adjuster.
It will in fact slide off.
Failing that look for a tiny drift pin (12-30 thou. dia.) in the vertical adjust knob and then set out to find a drift that will move it.
Check carefully for the pristine end and drift that end NOT the broomed end.
I use jeweler's drifts but you can carefully grind a small steel drift back far enough to allow you to start the pin and then use a hat pin (end broken off) to take it the rest of the way.
Knob comes off. Screw shaft unhooks, and it's in your hands with W/adjuster which then comes apart.
After fix, and before reassembly give the frame a little vertical spread to remove any sloppiness in the screw shaft arrangement. Your sight looks abit cockeyed to these old eyes.

NOW go back and soak that sight in diesel or release oil. The above ain't fun
Oldguncrank

 

[H Wally]

H/W
You should expend all efforts with release oil. heat, and perseverance first to free the windage adjuster.
It will in fact slide off.
Failing that look for a tiny drift pin (12-30 thou. dia.) in the vertical adjust knob and then set out to find a drift that will move it.
Check carefully for the pristine end and drift that end NOT the broomed end.
I use jeweler's drifts but you can carefully grind a small steel drift back far enough to allow you to start the pin and then use a hat pin (end broken off) to take it the rest of the way.
Knob comes off. Screw shaft unhooks, and it's in your hands with W/adjuster which then comes apart.
After fix, and before reassembly give the frame a little vertical spread to remove any sloppiness in the screw shaft arrangement. Your sight looks abit cockeyed to these old eyes.

NOW go back and soak that sight in diesel or release oil. The above ain't fun
Oldguncrank

Hmm - I've never noticed a pin in the knob... guess that explains why I couldn't figure out how to disassemble everything!!!

You're right - the sight in the pic does look a bit off - fortunately I pulled them from the internet for clarity about what's being discussed - didn't have much in the way of options to pick from

I've been soaking the darn thing in penetrating oil but I suspect it might've been forced and jammed at some point, so rather than just gunked up it might actually be mechanically jammed :/



Thanks again for the info on disassembly! Another thing learned!

 

[H Wally]

As an update for anyone else working on M10's, soaked the sight in penetrating oil and acetone alternating for several days and the drum freed up - was almost solid with hardened grease; brush wouldn't even touch it pre-soaking.

Also, the pin in the elevation knob is almost invisible on some guns - looks like they knurled the knobs after placing the pins, so you've got to look very carefully to find them!

 

[RRCo.]

Ultrasonic cleaner is what you need. If you want to take the sight apart, put it in soft vise jaws and bend the top and bottom of the sight frame toward each other until the bottom of the elevation shaft can be moved out of the recess it sits in. In your first photo above you show the bottom of the shaft and the conical shoulder on it that sits in the recess. The sight frame should spring back when released as that is what creates the tension on the elevation shaft. Swing the shaft out and the leaf will come away from the other side of the frame and can be unscrewed from the shaft and removed.

 

[Mk VII]

I'd guess slamming down onto the charger bridge over the years may have peened the threads on the windage worm, which was what happened to mine.