these where started by metal storm for a 30mm defensive perimeter gun ( border crossing) and took off but the ammo was put out to a US firm and they ran with it some more , the rounds are now accurate within a yard or so range wise , the connector and unit is digital but the old timer circuits are in the base of the round.. ours has a laser range fiter range setter , dunno about the US one , the US one is not 40mm either, and i doubt it would be the recycled bofors prox fuses used here when we where doing this in 2004

aussie development and US development are a tad different ..