Hi, everyone ~ I'm Chunzi - this is my very first year at FIEA! :D I'm very new to Maya and had never done it before. It's definitely a challenge but I see the result of getting to know and mastering it is gonna to be very rewarding! So here are the steps of how I was making the cannon. Although struggled a lot when making it, I'm learning tons at the same time! I will appreciate any advice on how I can make it better! Thank you ~ :)

I divided the entire process as two parts. Part 1 are the steps for setting up the reference, cannon body and the bottom. Part 2 are the steps for cannon back stand which I think it's harder to make.

Part 1 

Step 1 - Importing and setting up the reference first.

Step 2 - Now starting making the cannon body.

Step 3 - Adding the round part at the back.

Step 4 - Adding more details and the bottom.

Part 2

Step 5 - Brain gave me an awesome tut of how to make the back part, he made these on top my reference.

Step 6 - Imported to Unreal, will keep finishing it.

* Some different views*: