Originally Posted by
Bruce_in_Oz
The BIG problem with things like the Australian "HT" snipers and the Brit No4T series is that incredibly fiddly procedure to collimate the scopes, not entirely to the bore, but to the TRAJECTORY of the bullet. There is NO windage adjustment in either system; the scope had to be "optically centred and then the BASES were "tweaked" to bring a "nominal" zero onto the same POA as the previously adjusted "iron" sights. The original optics are of the "reticule-moving" type, not the more modern, "image-moving" items seen everywhere today. Thus a "perfectly zeroed" Patt 18 or No.32 may be seen with the "reticule" off-centre, both vertically and horizontally. A "perfect" set up would see the the reticule perfectly centred, On these old girls, this is achieved with LOT of tinkering with the bases / pads.