Lithgow No1 Mk3* Rear Sight Adjustment Question

The first milsurp I ever purchased was a 1944 No4 Mk1* Long Branch. I have since purchased many other milsurps but only had the one Enfield. I had wanted some variety of No1 Mk3. A friend of mine has a nice Lithgow and it seemed as though every part was of Australian manufacture so when I saw a Lithgow No1 Mk3* last week at my local gun shop for a reasonable price I grabbed it.

Like my friend’s Lithgow everything that has a mark seems to reflect Australia. The receiver is dated 1942 sn# E2032 but just about everything else that has a date is marked 1943 including the stock. Also, everything I have seen with a number matches. The barrel has the R in a circle which I’m told means it is a replacement but it is still dated 43 (8 43). The barrel is in good condition and the head space also checks out. I took it to the range today and it shot very well.

The only thing that did not work, or I should say I couldn’t get it to work is the rear sight adjustment. There is what looks like a button on one side and a knurled stud on the other. I assumed that you press the button take the pressure off the knurled bit and it will slide. If that is how it works then it has a problem. I pressed it and no movement that is no movement from the button it does not move in. There are no outward signs of rust. I applied copious amounts of Kroil with no luck. Has anyone here had this issue, is it common, am I missing something? Any pointers would be greatly appreciated. I have photos but have not sized them properly yet so not ready to post.

The knurled side is actually a thread cut at a steep pitch, the idea being that by rolling the knurled portion with the thumb, one can make very fine sight adjustments. The button is pushed if one wants to make a rapid sight adjustment and it should bring the knurled portion completely out of engagement with the notches cut on the sight leaf.

I should add that I too often need to push the button in somewhat to get the fine adjustment knurled knob to move without undue strain on my thumb on my No.1 Mk. 3*

Now there were some No.1 Mk.3 sights that were pinned at the lowest setting for use on Indian riot guns converted to a .410 cartridge. I would think it unlikely that one would find its way onto your rifle, however I would still check to make sure that there is no visible pin anywhere.