This is the biggest drawback. Propane is heavier than air and can settle in the combustion chamber, leading to unpredictable explosions or sustained flames if not managed correctly [5. 2]. Community Perspectives
The 130dB blast is extremely loud. Check local noise ordinances, as these are often restricted near urban areas [18]. propane-bird-cannon-diy
Never use less than Schedule 80 PVC for the combustion chamber to prevent shattering [5]. This is the biggest drawback