I suspect the string does have to do with the sleeving. It is very predictable so if in the most unlikely of chances I actually miss the first shot,

I'll aim three inches lower the next one and three more inches lower if I miss again. Like that will ever happen.

The 357 Max brass only comes up 1/10th of an inch short on the neck. I don't see this as an issue. The price difference is enough for me live with the necks a touch short.