Lol, you can better join the guild and make good friends. When you made your friends in the guild, then you can ask them for a help to get Elin's gun.

I give you tips to get Elin's gun very fast. You need 2-3 people who can catch stegosaurus. Let them catch all 4 stegosaurus at every battle and after every battle dismiss them.

Why to catch a stegosaurus? The answer is simple: to prevent to get more stegosaurus in the battle. If you kill 1 stegosaurus, then another stegosaurus will jumped in.

Every battle has 20 stegosaurs, so it needs 7-20 rounds to beat them in a battle. There are 4 battles in the row, it means: 80 stegosaurs total. But if 2 people can catch them, then it will ended in 2-4 rounds. Just catch 16 stegosaurs and then you finish the quest.

I warn some things more: those 2-3 people cannot catch a same type stegosaurus which is already in their pet bank or party. So, be sure that they don't have stegosaurs in their bank or party. And they also needs 3 free slots in the pet party.

To make fun more, you can ask them to have a match who has caught the most. And accidentally killing is punish point. In this way they can learn how to catch them effectively.