The VMCC Journal has articles about the Royal Enfield "New Bullet" on January 2016 and again on August 2017. The New Bullet was sometimes known as a "350 Crusader" for the parts commonality both machines had. It had a unit construction engine and was produced between 1963 and 1965. About 250 were made and many were exported. The machine was a bit of a flop in sales. A law had been passed limiting young riders to 250cc machines. Also, although it had a bigger engine than the Crusader 250, it was less sporty and slower, something one would not have expected with the bigger engine. In the end some were down converted to 250cc to see if they could attract young riders. Apparently it made a fine tourer machine. A Register of New Bullets was started by John Dove, he should be contacted at firstname.lastname@example.org by people interested.
Apparently the Register members met at the National Motorcycle Museum in July and someone presented a photo of a New Bullet, apparently from 1964 in War Department guise. The final destiny of that machine, 516 FUW, is unclear. If someone has more information, please contact the Register.