Model shows objects inside it

Hello their, I have a problem with a crappy model I made which is a rocket launcher, when I put the rockets in where the bullet hole hole would be, my model renders the object in front of it. I don't know why this is happening, I tried looking this up but no results. Here are some pictures to better explain what's happening:

This pic is what the rocket launcher is intended to look like in unity:

This pic shows what it's doing in the unity editor and in play mode:

So is this a simple fix? What exactly is happening? Is their another question that has been answered that is similar to mine?

Help would be appreciated.

Thanks for reading

:)

_1