I’m not sure, but higher damage seems to pulp faster. Logically it would take a long time to beat something to a pulp with a bow. Maybe carry a hatchet or something, or use a sharp object and use the (b)utcher menu. There is an option to “dismember” which almost always takes less than a minute. The yield is poor, but if you’re just pulping them you probably don’t care and just don’t want them getting up again.
