All my guns and bows are rapid firing...

Anyone know what on earth might be causing this? Whenever any of my pawns shoot, whatever weapon they are using hoses out like 99 bullets a second. Nothing stands a chance. It's hilarious but not very balanced. Only happens on one save file. Still happens when all mods disabled.

Whilst it's happening the log shows this error:

Exception ticking [Pawn name] (at (114, 0, 159)): System.NullReferenceException: Object reference not set to an instance of an object

at RimWorld.HistoryEventsManager.RecordEvent (RimWorld.HistoryEvent historyEvent, System.Boolean canApplySelfTookThoughts) [0x000b3] in <a7463a06f2454dfcb1840bc06cbe4fd3>:0

at Verse.ThingWithComps.Notify_UsedWeapon (Verse.Pawn pawn) [0x0006c] in <a7463a06f2454dfcb1840bc06cbe4fd3>:0

at Verse.Verb.TryCastNextBurstShot () [0x0016f] in <a7463a06f2454dfcb1840bc06cbe4fd3>:0

at Verse.Verb.WarmupComplete () [0x00013] in <a7463a06f2454dfcb1840bc06cbe4fd3>:0

at Verse.Verb_LaunchProjectile.WarmupComplete () [0x00000] in <a7463a06f2454dfcb1840bc06cbe4fd3>:0

at Verse.Verb_Shoot.WarmupComplete () [0x00000] in <a7463a06f2454dfcb1840bc06cbe4fd3>:0

at Verse.Stance_Warmup.Expire () [0x0000a] in <a7463a06f2454dfcb1840bc06cbe4fd3>:0

at Verse.Stance_Busy.StanceTick () [0x0002a] in <a7463a06f2454dfcb1840bc06cbe4fd3>:0

at Verse.Stance_Warmup.StanceTick () [0x002a0] in <a7463a06f2454dfcb1840bc06cbe4fd3>:0

at Verse.Pawn_StanceTracker.StanceTrackerTick () [0x00016] in <a7463a06f2454dfcb1840bc06cbe4fd3>:0

at Verse.Pawn.Tick () [0x00086] in <a7463a06f2454dfcb1840bc06cbe4fd3>:0

at Verse.TickList.Tick () [0x0015c] in <a7463a06f2454dfcb1840bc06cbe4fd3>:0

UnityEngine.StackTraceUtility:ExtractStackTrace ()

Verse.Log:Error (string)

Verse.TickList:Tick ()

Verse.TickManager:DoSingleTick ()

Verse.TickManager:TickManagerUpdate ()

Verse.Game:UpdatePlay ()

Verse.Root_Play:Update ()