GB put it very well. For 99 % of those who are reloading they have no business thinking about loading for wildcats. The other 1% are those with little reguard for their own safety. It is easy to prove on paper the advantages of the wildcat round, but almost imposiable in the field. Depending on the wildcat you build the dies will cost from $50 to alittle over $100 and that will buy you enough extra brass to make up for the shorter life of the standard round, if it is indeed shorter. The main thing, with any round you shoot, is getting the best accuracy from it you can. An extra 100 fps will get you abt 5 yrds more point blank range, ie your .22-250 has a point blank range of 300 yrds. so if you increase the velosity another 100 fps, with the same bullet, you can not hit just as accurately at 305 yrds.
There is a place for wildcat round and that is the people who just love to play with thing that are different AND ARE WILLING TO TAKE THE TIME TO LEARN HOW TO BE SAFE DOING IT. Even then things can go wrong. With most rifle rounds you can safly work with 50,000 to 60,000 psi., but it take very little to push the presures to 100,000 psi., and the gun becomes a bomb.