It is roughly oblong, about thirty metres along its longer axis and ten metres across, and it sits in the kind of soggy pasture that tends to preserve earthworks well. The explanation for its existence is considerably more recent and more mundane than a burial mound or a ringfort: it was built as a rifle butt, the thick earthen backstop at the end of a shooting range.

The range appears on the Ordnance Survey twenty-five-inch map, produced in the late nineteenth century, where the mound is marked with hachures and annotated simply as "Butt", with "Rifle Range" extending 800 yards to its north-east. It does not feature on the earlier 1838 six-inch map, placing its construction somewhere in the intervening decades, a period when rifle ranges of this kind were established across Ireland in connection with the Volunteer and militia movements as well as regular army training. By the time the 1919 six-inch revision was made, the range itself had been dropped from the cartographic record, suggesting it had fallen out of use, though the mound itself was still considered worth marking. Whatever organisation once fired down that long stretch of Mayo ground, their range is long gone; the butt quietly remains, doing nothing now except holding its shape in the wet grass.