This is similar to my guide for "Goldmember", but I've updated it (10/01/2019) to include DLC (as much as I can)
After scoring a kill and harvesting your trophy, you will be awarded with a score. The scoring thresholds are as such
0 - 399 - No Rank
400 - 599 - Bronze
600 - 799 - Silver
800 - 949 - Gold
949 - 1000 - Diamond
It should be noted that it is not possible to score a Diamond rating on females EXCEPT Gemsbok
This is because females either do not have a trophy rating (antler animals) or their trophies will never be large enough to net the highest score (in the case of bears, foxes, coyotes etc)
In order to score a diamond rating, you will need all three of your bonuses to be at 100%
Quick Kill
You earn 100% quick kill bonus by dropping the animal on the spot
Update - 06/02/19
As of the update on 5th Feb, this is now easiest earned with a double lung shot (on any animal) using the highest caliber allowed on the animal (eg: .270 for Wild Boar, .338 for Moose, etc).
Integrity
Integrity bonus is awarded at 100% by killing an animal with the "correct" caliber of weapon. The smaller the animal, the smaller the "permitted" caliber. For ease I have listed the maximum caliber allowance for rifles on below - All animals (including DLC), listed alphabetically
Axis Deer - .243
Black Bear - 7mm Regent Magnum
Blackbuck - ,243
Blacktail Deer - .243
Blue Wildebeest - 7mm Regent Magnum
Brown Bear - .338 Rangemaster
Canada Goose - .223 Docent
Cape Buffalo - .470 Nitro
Cinnamon Teal - .223 Docent
Coyote - .243
European Bison - .470 Nitro
Fallow Deer - .243
Gemsbok - 7mm Regent Magnum
Jackrabbit - .22LR
Lesser Kudu - .270
Lynx - .243
Mallard - .223 Docent
Moose - .338 Rangemaster
Mule Deer - 7mm Regent Magnum
Musk Deer - .223 Docent
Puma - 7mm Regent Magnum
Red Deer - 7mm Regent Magnum
Red Fox - .223 Docent
Reindeer - 7mm Regent Magnum
Roe Deer - .243
Roosevelt Elk - .338 Rangemaster
Scrub Hare - .22LR
Side Striped Jackal - .243
Springbok - .243
Warthog - .270
Water Buffalo - .470 Nitro
Whitetail Deer - .270
Wild Boar - .270
Anything larger than the caliber listed will result in integrity being less than 100%, and Diamond rating being un-attainable
Consecutive Harvest
Each time you start a new hunt you will start with this at 0, and it raises by 20% for each kill you harvest, after the first kill, so you will need to kill 5 animals before hunting for "trophy" scores
1st Kill - 0%
2nd Kill - 20% (this is your first "consecutive harvest")
3rd Kill - 40%
4th Kill - 60%
5th Kill - 80%
6th Kill onwards - 100% bonus
SCORING THE DIAMOND RATING
With all of your bonuses at 100%, you now want to hunt high scoring males
Without perks this can be difficult to establish, so as a rule of thumb you want to be trying to use the animals "difficulty" as a benchmark
To score a Diamond rating you need to be hunting the highest difficulty levels for each animal, as "difficulty" is an indication of trophy size (and most of the time you can visibly see this)
The difficulty levels go from 1 (Trivial) to 9 (Legendary) but not every creature can hit level 9.
Listed here are the maximum difficulty levels for each animal, and (where known) the maximum "Trophy Rating" for each animal (These numbers are still a work in progress for the latest DLC reserve)
NOTE
There is a skill which you can unlock which will tell you the trophy rating "range" when spotting an animal. It is not necessary for the trophy score to be the absolute maximum, but if, when spotting an animal, it's "trophy score" range doesn't go up to the number listed below, your animal will almost certainly not score a diamond rating.
3 - Very Easy
Cinnamon Teal
Jackrabbit - (6)
Mallard - (2.1)
Musk Deer - (276)
Roe Deer - (277)
Scrub Hare - (6)
Whitetail Deer - (213)
5 - Medium
Axis Deer
Blackbuck
Blacktail Deer - (210)
Blue Wildebeest - (162)
Canada Goose - (9.2)
European Bison - (300)
Fallow Deer - (237)
Gemsbok
Lesser Kudu - (35)
Moose - (245)
Mule Deer
Reindeer - (904)
Roosevelt Elk - (404)
Springbok - (116)
Warthog - (63)
Wild Boar - (159)
9 - Legendary
Black Bear - (24)
Brown Bear - (29)
Cape Buffalo
Coyote - (59)
Lynx - (28)
Puma
Red Deer - (276)
Red Fox - (15)
Side Striped Jackal - (31)
Water Buffalo
PLEASE NOTE
The level of the creature is merely an indication, and on occasion you will find that even a max level won't be quite enough to net you Diamond, if their trophy rating is at the bottom of the scale (these will score somewhere between 920 and 949 in my experience)
Good luck
