Nothing wrong with the AI version. I have had an AI version in both the 30-06 and 35 Whelen. Didn't gain anything ballistically in the '06 and not needed for headspace control because the '06 shoulder is more than adequate. Nothing gained ballistically in the 35 Whelen AI but it did increase headspace control which increased case life. Loss of headspace control becomes very apparent in the 35 Whelen when shooting low pressure, cast bullet loads. Full pressure loads simply reset the primer while stretching the case rearward... thus masking the stretch that has already happened. If any thing, the 338-06 version may help prevent case stretching, albeit likely it will be a very small amount as the shoulder on the 338-06 is adequate, in my experience. Anyone with a regular 35 Whelen or 375 Whelen or 40 Whelen can test the theory in their own rifle.
Resize a case as per normal. Prime it. Shoot it. Inspect primer protrusion in the fired case.
For larger than wildebeest, I just use a 375 HH or 416 rem Mag. BTW, 375HH and 416 Rem Mag work great on smaller antelope like impala. Doesn't waste meat, ruin hides or capes by blowing big holes.