The A2 Hannibal was made from both P14 and P17 Enfields. But this is not a way to save money as the acftion has to be completely rebuilt, including construction of a new magazine box from scratch.

The cheapest way to make a 500 A-Square is to get a cz550 action set up for the 416 rigby and add a barrel to it. Very little will need to be done to perfect feeding. The extractor will need to be tightened a little. Add a second recoil lug and put on a stock. For aesthetics you may want to replace the ugly cz550 bolt handle.