After more material was found yesterday, searches by gardai close to the Monaghan-Armagh go on as second border for explosives are expected to continue in the coming days.
Yesterday's search team found a plastic barrel containing a quantity of mortar parts as well as ammunition.
Some of the ammunition is for firearms not yet recovered and includes bullets for the "sniper" Barrett rifle which has been used by the Provisionals in the past.
On Wednesday a large number of rifles was found in another larger barrel about 500 metres from yesterday's find.
Ballistic tests should confirm whether any of the firearms can be linked to previous incidents.
The second barrel found yesterday contained ammunition for Kalashnikov rifles, 12-gauge cartridges used in shotguns and three revolvers, as well as impact fusing units which are used to set off mortars.
"This is an active service unit's hide and we are waiting for ballistic examinations which will determine whether they were used in any incidents," said Garda Insp Noel Cunningham who is co-ordinating the searches. They began three weeks ago and are expected to continue for the foreseeable future.
All the firearms were in excellent condition and possibly hidden in the barrels after use. How ever, the barrel found yesterday had leaked and the items had started to corrode.
As gardai from the Louth/ Meath and Cavan/Monaghan divisions have already found firearms and mortar parts, explosives and other bomb-making materials are expected to be found in the same locality.