Jamie Morgan now faces a lengthy jail-term following the find in February 2017.
Police had carried out a search close to the private Windyhill Golf Club in Bearsden, East Dunbartonshire.
Officers discovered a black bin bag with three revolver guns as well as a knotted sock containing a quantity of ammunition.
Forensic tests were then carried out on the items.
Prosecutor Lindsey Dalziel said Morgan was one of “two major DNA contributors” found on the bullets.
Morgan, of Birmingham, made no comment when later quizzed by police.
The 28 year-old today/yesterday pled guilty to possessing ammunition without the relevant firearm certificate.
He had also faced charges today/yesterday in connection with the guns, but his not guilty pleas were accepted.
His lawyer Ewen Roy told the court: “His position is that he held the ammunition on behalf of another.
“He then handed the cartridges back to the person he held them for. He had hold of them for a few days.”
Lord Mulholland remanded Morgan in custody pending sentencing next month.