I have recently started converting 30-30 Win to .225 win cases. The hardest part is using a lathe to change the rim diameter and thickness to the proper dimensions. I am using a micro lathe with toggle indicators, and the conversion is easy to do. the forming dies are available from Huntington thru RCBS for about $85. With 20 rounds going for about $60 from win when they are available, The cost of the equipment can be offset. If you use once fired, you might need to anneal the neck for the first try. I have been able to avoid this step, but will anneal after fire forming. After this necessary step, the reloading is the same as any other cal.
I havn't fired any yet because of health issues, but hope to soon. The forming charge should be reduced below max about 2 gr because of the lower case capacity. my rifle is a 1964 Win 74.