i was just sorting through some recently purchased parts and came to a SMLE nosecap.
It looks like a slightly battered standard job, except, the barrel hole is a simple round hole. Every Mk111* nosecap I have ever seen has the little extra cutaway section at the top of the barrel hole. The corner points of this cut-out are part of the bedding for Mk7 ammo.
The serial number on this nosecap is V 6537 and it carries a tiny EFD and arrow mark just forward of the sword bar. Thus, it is British, and acoording to the published information, if part of a Mk111, made by BSA, or if a 111*, it could be a BSA, RSAF, SSA, or NRF No1. But is it from an early Mk111 that was set up for Mk6, or earlier, ammo?
The only reference I have found so far is in the usual place, Mr. Skennerton's epic tome. This notes that, on the Mk1 nosecap, there was to be a clearance of 0.002" between the muzzle diameter and the hole in the nosecap. No mention of any special bearing points. However, this is definitely not a Mk1 nosecap.
The component illustration for a Mk111 on page 146 clearly shows the extra cut in the barrel opening of the nosecap.