This paper discusses the function of Late Glacial arch-backed and tanged projectile points from northern Europe in general and southern Scandinavia in particular. Ballistic requirements place clear and fairly well understood constraints on the design of projectile points. We outline the argument that, based on metric considerations, arch-backed points (pen-knife points or Federmesser) most likely were part of a bow-and-arrow weapon system, while large tanged points (Bromme points) most likely tipped spears propelled with the help of a spear-thrower/atlatl. This paper then presents a comparative symmetry analysis using the Flip Test of Hardaker & Dunn (2005) and an analysis of the tip angles of Late Glacial points. While these analyses do reveal a trend towards greater symmetry over time, the often very wide tip angles of the large tanged points indicate that these armatures, whilst surely fully serviceable, diverged considerably from the functional optimum predicated by ballistic theory. These observations relate directly to southern Scandinavian Late Glacial culture-history which is marked by a sequence of co-occurrence of arch-backed and large tanged points in the earlier part of the Late Glacial, followed by a disappearance of the slender backed points, later to be followed by a miniaturization of tanged points. This can be interpreted as reflecting an initial parallel use of bow and spear-thrower, followed by a loss of bow-and-arrow technology, and a subsequent reintroduction of this technology. Furthermore, our analysis suggests that the function of, in particular, the large tanged points may have been compromised by their highly variable morphology. Coupled with the generally lower economic utility of the spear-thrower when compared to the bow-and-arrow, the suggested loss of bow technology in the Bromme culture probably would have had substantial demographic implications. The loss of bow technology in southern Scandinavia went hand in hand with a reduction in typological and technological complexity and we interpret this loss of ostensibly adaptive technologies in light of Henrich’s (2004) demographically driven model in which population size, density and connectedness scaffold cumulative cultural evolution. Finally, we suggest that it was the Laacher See eruption (12,920 BP) that cut southern Scandinavian hunter-gatherer populations off from continental European groups leading, via demographic fluctuations, to the ‘disappearance of useful arts’ (Rivers 1912) reflected in lithic technology.