I get the asthma thing. That's the best reason of all for switching. Belted magnums. I load those too. 7mag, 300 WM, 8 Mag, 7 STW. I only neck size those cases. FL sizing over time will create a problem. The problem is when FL sizing belted cases you have to stop above the belt. Brass will build up over time and the cases will NOT chamber. Innovative Technologies makes a special collet die to correct the problem. But neck sizing removes that little problem and reduces stress on the cases. As long as those cases are shot in the same chamber.