A flamethrower was among the 355 firearms and 70kg of ammunition surrendered to police since the start of the national gun amnesty on July 1.
Police have described the outcome as "pleasing", with a large number of unregistered rifles and shotguns handed in.
ACT Firearms Registrar Detective Sergeant Rod Swain said that in the previous 2017 amnesty, 700 weapons were handed in over a three-month period.
"To have half that number surrendered in one month is a great boost to the safety of our city," he said.
"Each of these firearms will be destroyed or properly registered. Those destroyed will not be able to fall into the wrong hands and be used for criminal activity."
"We maintain our call for anyone who has unregistered or unwanted firearms, ammunition and other weapons to bring them to our facility in Mitchell."
World War One era rifles and a 100-year-old former USA military pistol have been among the surrendered weapons. Firearms of historical significance will be offered to museums for their collections.
Also sought for surrender under the amnesty are gel blasters which are legal for possession in South Australia and Queensland but not in NSW or the ACT, which creates the potential for mixed messages to be received by the public.
It is estimated there are thousands of gel blasters in public hands in the ACT and regional area. Gel blasters are expressly designed to imitate conventional firearms and there have been instances interstate where police have mistaken them for real firearms, and had to shoot.
The amnesty is a joint initiative with ACT Crime Stoppers with the region's chair Diana Forrester reminding the community of their obligations.
"All of us have seen the harm caused by the unlawful use of a firearm. Not just to the victim, their friends and family, but also the impact on the community confidence that often follows, which is why we all have a part to play in making our community safer - that's our aim," Ms Forrester said.
Anyone with information about illegal firearms should contact Crime Stoppers on 1800 333 000. Information can be provided anonymously.
People wanting to surrender their firearms or firearm-related items can do so at the ACT Firearms Registry at the Exhibition Management Centre, 86 Vicars Street, Mitchell during business hours.
More than 57,000 weapons were handed in nationally during the 2017 amnesty.
