Weapons Expert Guide RDR2
Expert 1 - Kill 3 enemies with a knife
You will automatically complete this task during the story mission called Paying a Social Call, which has you stealth killing a bunch of bandits, but otherwise we recommend using Arthur’s knife as a covert weapon to get these kills, as it quickly uses its viability when enemies start whipping out their firearms.
Weapons Expert 2 - Kill 3 enemies in 10 seconds using only throwing knives
During the same story mission, Paying a Social Call, you’ll receive a set of throwing knives. Equip them, and use the deadeye to chuck several at various enemies in succession, aiming for the head to ensure a kill, and this challenge will be completed.
Weapons Expert 3 - Kill 3 birds of prey using only a tomahawk
This one’s tricky. You can buy tomahawks from the Fence at Emerald Station, but it’s not exactly a cakewalk to hit falcons and owls out of the sky with the projectile, even when using deadeye. The best trick I’ve found is kill an animal or bandit before leaving their body to rot for a while, in the hopes of attracting any nearby birds of prey to descend upon the free meal. Otherwise, some birds can be found perched stationary on rocks near rivers, and Fences at farms, but it may take you a while to get all three.
Weapons Expert 4 - Kill 10 enemies with a shotgun using crafted ammo
You can craft shotgun ammo from the crafting menu at a campfire, and the easiest option is to create Split Point bullets using your knife, as this doesn't require any other ingredients or recipes for you discover as a prerequisite. Following that, equip the right bullets using the weapon wheel, before offloading them into any nearby humans.
Weapons Expert 5 - Kill 5 mounted enemies, using 1 throwing knife per kill
Throwing knives aren't exactly the most dangerous tools in Arthur's arsenal, so you'll need to score headshots to ensure you get the kill with a single hit per knife. For finding enough horseback enemies, rack up a bounty of over $200 in one state, and a bunch of them will hunt you down in no time.
Weapons Expert 6 - Kill 4 enemies at the same time with a single stick of dynamite
Dynamite can be bought from gunsmiths or crafted at camp fires, and you'll need to light and throw one into a crowd of conglomerated enemies for a chance of killing 4 with one stick. Their radius isn't as large as you might expect, so use Dead Eye if you need your throw to be as precise as possible.
Weapons Expert 7 - Kill 4 consecutive enemies by throwing and retrieving the same tomahawk
Tomahawks can be retrieved once thrown simply by running over to the spot where they landed, and Arthur will automatically pick it up. Like the throwing knives, you'll need to aim for the head to secure the kill on an enemy; rinse and repeat this process three more times in succession, and the challenge will complete.
Weapons Expert 8 - Kill 15 enemies using a long barrelled shotgun
Long barrelled shotguns can be bought and customised from gunsmiths in towns around Red Dead Redemption 2, so purchase one, take it out to a nearby bandit camp, and fire away to easily finish up this straightforward challenge.
Weapons Expert 9 - Kill 9 unaware enemies from behind, using the bow
Bows are great for stealth kills as long as you guarentee one hit kills with headshots, so aim for enemies' noggins from behind for this challenge. Stay crouched and slow to avoid being spotted, and make sure you pick your arrows back up from their corpses to save on having to buy any more.
Weapons Expert 10 - Kill a grizzly bear without taking damage, using only throwing knives
Grizzly bears can be found in the more mountanous regions of Red Dead Redemption 2's open world, but killing one in this way is very, very hard. Make sure you have plenty of throwing knives (like, at least two dozen), and to avoid taking damage you'll need to have a strong degree of stamina to outrun the animal whenever he comes in for an attack. It'll be a slow, arduous fight, but worth it for finishing the entire Master Hunter Challenge set by the end.