A couple of L42 questions

[Peter Laidler]

As I remember it, the earliest barrels used standard No4 block band foresights but the specifications were too wide to accommodate the existing foresight blocks which could vary between not-go at all to just plain loose. So the barrel spec was increased. Now, the screw, protector foresight acted as the old pin, block band foresight would. It meant that each block band was machined to suit the barrel. That was the case up until the end. New barrels came machined down but the fitting of the block band foresight meant machining the internal diameter to the exact diameter required for that barrel. After that it was tinned and sweated in place. When cooled, a needle file cleared out the slot for the foresight protector screw.

I never heard of a thick walled block band foresight working loose as ours were always tinned as well as pinned although there were still a few in the system on older rifles but this is no doubt the cause for the change from thick walled to thin walled. In any case, a larger diameter barrel there is preferable in any case

The later, thin walled block band foresight had a smaller internal recess down the left and right of its length - the vestiges of its previous .303" rifle days. You could fill these narrow gaps with solder while sweating and aligning the block band. This kept it fully secure and trouble free thereafter

We had a few old trials barrels here at Warminster with both small and larger diameter muzzles