I got a C02 inflator and decided to learn how to use it rather than get a bad surprise on the road. To simulate a tube change:
1. I deflated my front tire.
2. Put a touch of air in using the C02 inflator, to simulate verifying the tube was not pinched.
3. Filled with inflator and checked pressure with a gauge. It read 180 psi. This was from a 16 gram cartridge.
4. Deflated the tire.
5. Re inflated the tire using a floor pump.

Next day tire is flat. What am I doing wrong?

Thanks!