If you need a replacement piston and sleeve for your .25 Savage , the Ofna 52042 is a direct drope in sleeve and piston , If you can reuse your rod if not you can get a replacement rod from Ofna . way less and easier to find than HPI . I Payed $27 for a sleeve and piston on eBay and I can't even find a .25 sleeve and piston from HPI and the ones they have are 120 and not available