I've got a Hoy mini-pump (very similar to the always well-reviewed Lezyne Road Drive) and it has a tendency to unscrew the valve core on removal. User error? Bloody frustrating at the side of the road, typically because you'll knacker the core removing it from the pump head, resulting in the Walk of Shame and a binned replacement tube. What am I doing wrong? For tubes without removable cores I've also had it bend the valve core.
Tempted to go with a full-size frame pump to replace it - welcome recommendations on that. I'm running 25mm tyres and will need to get them to 100psi as I'm a heavy rider.