Xring
I have just had my #1 tropical rechambered from 458 to 450 3 1/4 NE. The breachblock does have to have the loading groove opened out to enable the rifle to be loaded easily and to ensure proper extraction/ejection. It is the rim of the 450 that causes the problem if you do not have it done. I am extremely happy with mine and it shoots extremely well. I am putting a decerator recoil pad on it and a NECG aperture sight. I shoot both black powder loads and nitro loads in comp. The open sights will be for black powder and the peep light for nitro and hunting. I have had no extraction or ejection problems. I had the front of the safety flattened a bit so the cases clear the action during ejection. This is absolutely a must for quick follow up shots when I get a chance to go after Water buffalo in the Northern Territory next year. I hope you enjoy your new toy.