I've never been an expert on OAL and how it effects accuracy. But when loading for bolt guns with magazines, and especially that short action of the WMS's, I typically load them to the length to where they reliably feed down in the magazine well. If accuracy is good, I sight in. If you want to play later, I would load batches cinching down the die seater screw a turn or a turn and a half at a time and see what happens.
