Identification of two cal 50

Here are two cal50 I can’t identify.
Thank you for your help

I found the K 66 L11A2 as one of the experimental series of dark-ignition incendiary tracers.
It is listed in Conjay Arms catalog 1981. I could not find the short spotter round.

The smaller of the cartridges might be the 12.7x76 spotter.

Kynoch 1976

According to Fuchs:

The blue/black is incendiary tracer… Could be dark ignition but not sure?

The shorter round is a .50 BAT spotter I don’t see Orange tip with 1s/1s cannelures anywhere in spotters in Fuchs’ books but he does classify “Orange (Target Marking) Ball UK” as well as orange for IT. 1s/1s tends to be ball with some API/APIT classes.

Thanks to ron3350,Sam3 and jestertoo for the answers and links.


Another good reference

The L11A2 should be a observing/ranging round with a yellow over red tip as used on the Centurian tank,the only other coloured tip found with this headstamp would be the proof round which had an inert filled projectile with a ‘mustard’ coloured tip, I think someone has been playing with the one in photo.
The 50 BAT round could well be one of many different coloured tips that you can find during the development of the X7E2 experimental BAT spotting round, which did not go into production in the UK as it turned out to be cheaper to buy in the US M48A1 version of this round

@TonyL I show a bunch of variations in colors in K 66 L11A2 to K 68 L11 A1 in Fuchs book as well as my own collection. Yellow /red and mustard were the standardized, but there were a bunch of experimentals. Much like the 7.62x51 tracer trials.