I think feeding issues were the reason they converted them to 458Lott in the first place - the longer case reduces the angle feeding into the chamber to try and prevent the bullet getting caught up inside the extractor cutout inside the action.

My rifle had feeding issues and the previous owner had the ramp modified but with no success - he got a refund from where he bought it, and it was about to be parted out. I got it at a reduced price. I think there is something in the way the action is cycled. With the pointy Woodleigh 400gn PP, the issue is non-existant 99% of the time. Even the lead slugs didn't present too many feeding issues, but the 510gn Winchester factories jam almost all the time due to the round fat tips. (Note: Jamming only occurs from cartridges in the LHS of the magazine for the reason described earlier.)