Я, будучи не совсем в курсе вопроса сейчас быстренько глянул несколько статеек о 17 вечных мушкетах.

In 1988 the curators of the Zeughause Museum in Graz, Austria performed some experiments with the arms and armour in their collection. Among the various experiments was to fire original weapons at an original breastplate. The results were quite interesting. At «normal» combat ranges (15 feet/5 meters for pistol, and as I recall 100 feet/30 meters for musket) the breastplate was well pierced by all. However, certainly with the pistol (an original wheellock pistol with a muzzle velocity of over 1500 fps), while the bullet pierced the breastplate, it did NOT pierce the two layers of heavy linen behind it. Thus one could argue that both the pistol and the breastplate did their jobs. The pistol ball certainly would have incapacitated the wearer, but the breastplate may well have protected the wearer from death. Interesting.

While sixteenth-century military writers like Sir Roger Williams and Humphrey Barwick may well have exaggerated the power of the musket, it's worth noting that period muskets apparently took much heavier powder charges than in any modern experiments I know of. Williams wrote that muskets got eight to twelve shots from a pound of gunpowder, which makes a charge of over 30 grams likely. Writing earlier in the sixteenth century, Niccolo Tartaglia recommended a charge of about 50 grams. Only the heaviest gun the Graz tests used 20 grams of powder, and that one managed nearly 7,000 joules at the muzzle. A shot from this gun so charged penetrated 4 millimeters into a steel target at 100 meters. We don't know exactly how period gunpowder compares with the modern stuff used in the test, but it's possible well-charged sixteenth-century muskets achieved muzzle energies of 8,000 joules or more, which would have been required to approximate the performance described by Williams and Barwick.