CORRECTION TO EARLIER POST
In what I originally posted here I said that I had successfully crimped contemporary bullets (as supplied by British Wiring) on imperial conductors (an original 1969 T120 wiring harness).
When I went over to the shop today I realized that the harness laying on the bench, the one I used for my bullet experiment, was NOT the original, but a British Wiring reproduction! No wonder those conductors went in so snug and crimped down so tight.
When I retrieved the original harness and crimped a #14 bullet onto one if its 14-strand conductors I discovered that:
A) The wires did not fit so snugly in the bullet, they were actually quite loose
B) It didn't take too much of a yank to pull the strands right out of the bullet.
Which is exactly what Stuart said in his post above
Apologies for confusion I created. Thanks to koan58 for heads-up.