I saw that the italian 12,7mm machine gun ROF has been improved. Here are some specs and a pic that could be interesting for HTC (courtesy of Ferdinando "Veltro" D'Amico):
12,7x81SR Italian Breda aircraft cannon, HEIT bullet, m=37,5g, high explosive: 1,0g PETN + Magnesium + wax, l=51,75mm, Vo=792m/s, ol=107,8mm, om=85,0g, 8,0g propellant, brass left thread fuze with spin-band safety, headstamp: BPD | S | 39, bullet has dark blue color, fuze unpainted.
12,7x81SR Italian Breda aircraft cannon, APIT bullet, m=37,0g, incendiary: ~1,0g Zinc-oxidizer mixture, l=50,8mm, Vo=792m/s, ol=107,1mm, 8,2g propellant, headstamp: BPD | S | 41, white reduced bullettip.
12,7x81SR Italian Breda aircraft cannon, API bullet, m=37,0g, incendiary: White Phosporous, l=49,3mm, Vo=792m/s, ol=106,9mm, 8,2g propellant, headstamp: SMI | 943, blue bullettip.
