This limit is currently accepted by nearly all radiocarbon dating practitioners.
It follows that the older a date is, even within this 'limit', the greater are the doubts about the date's accuracy.
When they strike ordinary atoms in the upper atmosphere, the cosmic rays smash them apart. Some of these neutrons then collide with nitrogen atoms.
This collision is less destructive than the initial collision that produced them.
Radioactive carbon (Carbon 14) is formed in the upper atmosphere as a byproduct of cosmic radiation.
Cosmic rays are positively charged atoms moving at enormous speeds.
Such enthusiasts continue to claim, incredible though it may seem, that "no gross discrepancies are apparent".Radiocarbon dating has somehow avoided collapse onto its own battered foundation, and now lurches onward with feigned consistency.The implications of pervasive contamination and ancient variations in carbon-14 levels are steadfastly ignored by those who base their argument upon the dates.They found large variations in the radiocarbon 'dates' of objects of known age sent to 38 radiocarbon 'dating' laboratories around the world.Thirty-one of the labs gave results that the British group called unsatisfactory.