Oneshot does not contaminate powder or primers. Don't worry about that. Yet another reason to use Oneshot. I've used it for quite a while and the rounds always go bang.
The 1.760" measurement for max case length is the standard found in all handbooks. When cases exceed that, you trim to 1.750". If the max length is not specified, it's usually listed as .01" longer than the "trim to" length.
If you want to shoot...shoot...don't talk! Tuco
USAF Munitions 1969-1992