Updated: Dec 26, 2019
... and then ensuring that where the bullet goes it will put the beast down rapidly and kill it quickly
Assuming that every hunter who considers a visit to Africa for buffalo hunt understands the two measuring systems (Rowland Ward (RW) and Safari Club International (SCI), here is a quick review of how that is accomplished.
Look again at this diagramme:
The measuring tool (usually a thin steel cable consisting of wound strands is used to obtain the raw length. This cable is then later taughtened against a calibrated and approved steel measuring tape and the measurement in inches given.
The cable is held from the very tip, pressed piece by piece along the outside radius of the horn. Where the boss is encountered, carry on against the skull along the imaginary natural curve of the horn around the lower radii of the boss, down the natural curve again until the lower outer radius is met, then around the outer radius to the opposite tip.
A sliding tool not unlike carpenters' trigger clamps is used to measure the outside diameter of the spread of the horn after a 30 days dry out time after the hunt. Then, along the bosses the diameters between the longest radii are measured. These latter measurements are never used in expressing the RW value but is kept on record, and used where application for position in the RW grading list when simmilar value outside spreads already exis.
The SCI figure clearly is of a higher number than the mere outside spread of the horns as in the RW system. Look at the photo of the young bull underneath:
The pronounced curve of the horns and elongated sharp tips allow for a reasonably good SCI score - and indicate the reason why the historical chasing of SCI scoring by trophy hunters had been the reason of the depletion of valuable genes. This bull must never be shot because it may not even have started breeding. Personally I discourage hunters to ask for high SCI numbers when enquiring after buffalo.
Look at the following photos randomly taken off the internet in order to demonstrate the field judging of buffalo trophies according to the Rowland Ward measuring system:
A youngish (6 year old) bull with about a 42" RW measurement. It has a high SCI figure and will be a high dollar fetcher if marketed into that collector niche - but it is too young to hunt. It is in its prime years as a breeder, still leaving very good genes. Five years later it will be a 46" at least and then will be a beautiful RW trophy.
This is a 42+" high dollar bull. It is older than 8 years. It may or may not be breed anymore - if it has bachelor buddies it is celibate. The horn shape impresses me more than some 48 inchers I have seen. His little impressed demeanor towards the vehicle from which the photo was taken, displaying his character, also impresses me. Width is not everything - the evident character of the bull you shoot is your real trophy.
45" and starting the big league - these bulls are becoming available in South Africa, visiting hunters having been kept away from them the past 10-15 years all around the country in order to halt the trophy killing of good genes. This bull shows his 7-8 years age and he is of impeccable genetic makeup.
A 44" 6 year old bull - not to be hunted being too young. Very good genetic material - the results of years of holding back on bringing visiting hunters near the bearers of the old genes. One could say that the following photo was the same bull 10 years later.
Lastly, a 48 incher, showing the RW measurement way. A high dollar bull, big in body - at least 1,900 lbs. By the way, unless the visitor is 100% able to put the bullet exactly correctly, this bull from 40 yards may make the day interesting. Top of the heart shot, if two inches left of the proper aiming mark will damage the right lung lobe, and only that. He will live for at least a day and be mean as black death to any human he encounters.
To ensure the quickest death the bullet must cut open the heart top chambers. Even devastating the bottom chambers completely he can live for half an hour, so one should also break both elbow joints in such an instance.