A cache of guns was found wrapped in plastic bags and dumped in Sussex woodland.
Members of the West Sussex Wildlife Protection group were campaigning against hunting when they stumbled across the hoard of rifles.
The protesters were in woodland off Haslingbourne Lane, about a mile from Petworth, when they made the discovery on Wednesday.
Simon Wild, who heads the group, was called to the scene and informed police.
He estimated the guns had been dumped several years ago.
There were four rifles with wooden stocks, which Mr Wild said were probably 303 types and some years old. Much of the wood had decayed.
Police examined the weapons and removed them for disposal.
Mr Wild, who has had experience on a shooting range, said: "They are the type of firearm which needs a licence.
"Perhaps they got too hot to handle."
A spokesman for Sussex Police confirmed the weapons had been removed but would not speculate why they had been dumped.
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