CZ550 in 416 Rigby......is crimping the bullet necessary to prevent recoil from pushing bullets into case????

Better safe than sorry. BUT, reduce load and work up with crimp. Crimps increase pressure to various degrees. Average loads in moderate temperatures might not be noticeable, but max loads in 100 degree temps after sitting in jeep all day might be quite another. Would still probably be less exciting that having the bullet in the last round in the mag driven back in the case 3/8 of an inch...just hope your not holding it when its tried !

I sure like to crimp anything .338 and up. fire a couple of shots and see how much the noses are crushed in the magazine. I just started using the Lee factory crimp die for the .375, I really like the way it works.

I have found that I have to in my cz .416.

I too crimp evreything from 338 up using Lee crimping dies. I'm not sure it's needed on the 338 but with 250's it's probably a good practice.

338 on up sounds good to me, although my 340 Weatherby has done ok so far. I draw the line at the 375. On my 416, I ordered a Lee Factory Crimp die. It is not a regular stock item, but all you have to do is send them a dummy round and they'll do it for you. It works wonderfully.jorge