The round shot so far recovered from Bosworth battlefield can be classified according to their composition, their calibre, and the firing and impact evidence that they exhibit. Of the 31 projectiles of 28 mm and above there are 16 (52%) which appear to be of solid lead, 10 (32%) in which the lead sphere contain some form of stone, and five (16%) in which the lead sphere contains an iron dice.

Despite lead-stone composites comprising 32% of the Bosworth assemblage, not one of the 12 lead rounds recovered from other sites appears to contain stone, whereas seven (54%) contain iron dice. Towton has produced one solid lead and one with an iron dice; all three from Barnet are solid lead; all three from Flodden have iron dice, while from Pinkie three had iron dice and one was solid lead. The absence of stone composites may be simply because the sample from these other sites is so small. However, there are only three such rounds from the Mary Rose, which are also very unusual in being slightly irregular, having been manufactured by hammering lead around a pebble.¹¹² In contrast, the stone composites from Bosworth have all been cast in moulds. This might suggest that composites with stone progressively gave way to those with iron dice. If so then the transition was not complete, for lead-stone composite rounds are still recorded in 1547, though they only rarely appear in the list compared to lead-iron composites.¹¹³ However, there is also a lack of solid lead artillery rounds on the Mary Rose, so an alternative possibility is that we are looking at differences in the munitions used in a naval and battlefield context.

The one type of composite missing from Bosworth is a cast iron round encased in lead. There are just 29 of these from the Mary Rose, representing 11% of the assemblage of lead composite rounds. There is also one amongst the projectiles in the museum at Murten, Switzerland though here it appears only as partial wrapping rather than full casting with lead (Figure 7.19). Given the small numbers of round shot recovered from Bosworth, compared to the Mary Rose, their absence could simply be a matter of sample size.

Unlike solid lead projectiles, which remained in regular use for the smallest of artillery pieces in the mid-seventeenth century, with one special exception lead composite projectiles went out of use in England in the sixteenth century. 1595 was the last date at which the records of the Tower magazine report projectiles of lead containing iron dice, which were for use in small artillery pieces called falcons. While iron dice were still reported there in 1603, these were for use as hail-shot.¹¹⁴

In some examples the presence of this second material can be seen, either because part of it rested on the surface of the mould throughout casting (Figure 7.23) or because it has been revealed where lead was ripped away in an impact (Figure 7.20). Where visible, the stone is in the form of a single large pebble, a large chunk of flint, or flint shards. Where not visible at the surface, the presence of an inclusion can normally be established by comparing the diameter of the ball with its mass. All under-weight rounds were then tested with a magnet to establish which contain iron, with the remainder thus expected to contain stone.