The problem is that some people get carried away in the heat of battle, and 17th-century weapons can be lethal if handled carelessly. One moment you're loading gunpowder into a cannon; the next, one of your fingers has been blown off.
Yesterday, the Health and Safety Executive (HSE) turned its attention to this hazard and issued a booklet of guidelines for the 80 historical societies that have sprung up around Britain. It gives advice on issues such as maintaining weapons, storing explosives and keeping crowds at a safe distance.
The HSE wants to instil a sense of responsibility in the growing numbers of people who enjoy playing soldiers in their free time. But to prove that it is not a killjoy, it arranged for a Napoleonic cannon to be fired in the background as the booklet was launched.
The setting was Hoghton Hall, in Lancashire, a rallying point for Cavaliers at the outbreak of the Civil War in 1642.
Speaking in the house's 600-year-old baronial hall, Alan Duckworth, the HSE's chief inspector of explosives, warned that the re-enactment of history could be a dangerous activity. He gave a blood-curdling list of the kind of accidents that can happen. Earlier this year, for instance, a woman in Yorkshire had part of her hand blown off as a cannon that she was preparing to fire discharged itself prematurely.
In 1996 several members of the public watching a display in Humberside were taken to hospital after an artillery piece was fired at excessively close range. The same year a spectator in Yorkshire was injured after a cannon's powderkeg exploded.
The guidelines were welcomed by long-established groups such as the English Civil War Society and the Napoleonic War Society. They say their safety standards are high and suggest that some of the newer organisations may be less meticulous.
Michael Lawson, of the American Civil War Society, described the booklet as a "highway code" for battlefield enthusiasts. According to the HSE, the danger lies not so much with the replica cannon, muskets, pikes and pistols that are used to re-enact such famous conflicts as the Battle of Naseby, although the weapons themselves can be temperamental. "It's the gunpowder that is the main problem," said a spokeswoman. "You get someone loading a musket, they ram the stuff in, it misfires and then goes off in their face. "These people are so intent on reproducing the battle in the most authentic detail that sometimes they lose all rational thought processes. It is then that accidents will happen."
The societies say their members often sustain bruises during battles and occasionally broken bones. Other, more unusual, mishaps occur too. A few years ago a detachment of pikemen severed overhead cables and cut off the electricity to the Dorset town of Sturminster Newton.
One wonders what William Annetts would have made of the HSE booklet.
Mr Annetts, a colonel-in-chief of the Sealed Knot Society, one of the main Civil War groups, suffered a variety of "war wounds" during his many years of service.
On one occasion, it took a nurse 11 weeks to extract a four-inch pellet from his thigh after he shot himself in the leg at a "battle" in Jersey.
When Mr Annetts died earlier this year his ashes were, in accordance with his final wishes, discharged to the winds from a 17th-century cannon.