Don't use a heat gun for RAM chips.

You will almost certainly destroy the board — or the RAM, or both. A proper hot air rework station controls temperature and airflow precisely. A heat gun does not.

Heat guns are designed to strip paint or shrink tubing, not to gently melt solder on a multi-layer PCB. The air comes out fast and uneven, so you’ll either blow neighboring components off the board or heat the entire area so unevenly that the board delaminates. RAM chips are dense, with many pins close together. Even if you somehow get the chip off without visible damage, you’ve likely cooked the board or the chip to the point of failure.

Yes, people do it on YouTube. They also have spare boards and a lot of practice. For everyone else, the cost of a cheap hot air station ($40-60) is far less than the cost of replacing a motherboard or a laptop. Don’t learn this lesson the hard way.