375 Win is a good cartridge, I had one in a Marlin when they first came out, but its a waste in a big action like the P14/M17's. If you want a 375 that you can use on pretty much anything in Oz, without too much work gunwise, the 303/375 is your best bet. In a P14 it will do pretty much anything the JDJ will do with less work and cheaper brass. These " lightweight " 375's are great for anything from pigs to buff
If you really want to impress your mates go to the 375x2 1/2" flanged nitro express.....having that Nitro Express on the barrel really bumps up the ooh's and ah's factor....you can buy headstamped cases from Bertrams to show off, then make everyday cases from 9.3x74R or 405W cases. These big actions will take all you can give them, the only real limit is the quality of the brass you use.
We shouldn't really be hijacking old mates thread, so PM me if you want to go into it some more.
Roger
....and then there's Teddy Roosevelt's " big medicine " 405 Winchester.....sorry, couldn't help myself.....