As long as the case is pressed against the bullet, uniformly, during the seating of the bullet, a single shot does not require crimping, even when loading with 296 or 110, which I do. You can try crimping, but you won't notice any difference in the POI to that of non crimped. Just make sure all signs of the bell are removed during or after seating the bullet.
Crimping is only necessary, as stated above, when used in revolvers, to keep the bullet from backing out of the brass while it's still in the cylinder, when a previous round is fired.
I shoot a 44mag in a contender and have never crimped and never had a problem with ignition or grouping. Mine will bore one hole at 50 yards and hold 1-1/2" groups at 100yds, using 315gr hard cast and 296, without a crimp.