Popping a snake that size is very difficult. Their muscles are so strong by that size a beginner probably wouldnt be able to pop it.
You will probably have to get him probed.
Look up probing videos and you can get a probe kit online from a reptile supply store for around $30. Probing as well as popping can be dangerous as a beginner for the snake. So do your research or find someone in your area that is experienced and have them probe him for you.