I bought this used Davis Ind. Derringer .22 MAG and I'm using the 40 grain Maxi-Mag WMR from CCI at the range and it shoots good but it's so hard to eject the shell. It appears it's bulging at the end. The gunsmith at the range said that ammo might be too powerful for it. But it's one of the only brands I find at all the places that stock ammo. They have some from Hornandy, I think is the name, that's 30 grain. Should I be using something else? I have the owner's manual and it says to never use reloaded, hot-loaded or P+ series ammo. What is meant by hot-loaded? I've heard these Davis weren't the best quality but it was a good price and I think it's still a cool little gun so I'll keep it.