A Scots member of a far-right online group shared a video on how to make a replica sub-machine gun.
James Farrell joined Oaken Hearth sharing racist and neo-Nazi views with other bigots.
The 32 year-old's photos and comments included him claiming 'n*****s" were "sub-human" and also later stating: "It is about time someone firebombed a synagogue."
The ex-security guard went on to post a link to a clip on the making of "The Ultimate DIY machine pistol".
Farrell ended being held by police at his family home in Priesthill, Glasgow, following a large-scale probe into the Oaken Hearth group.
He helped get himself caught as being a member as a photo of a right wing book he had earlier posted had his dog in the background. Farrell later stated he thought the gun clip was "edgy and cool".
The first offender pled guilty at the High Court in Glasgow to a charge under the Terrorism Act. Prosecutors stated Farrell did "transmit" a video to the group with instructions on to construct the replica firearm.
This was said to have been a "direct or indirect encouragement" to the "commission, preparation or instigation of acts of terrorism".
The charge further stated Farrell was "reckless" as to whether the conduct had an effect. Farrell had his bail continued and will be sentenced next month.
He joined Oaken Hearth on March 11 2021 via the Telegram chat app under the user name "Jabz". Prosecutor Graeme Jessop said: "Once he was added, he made several anti-Semitic, racist and neo-Nazi comments."
On the day he joined, Farrell posted a photo of extreme right-wing books. Also in the picture were his dog and two bronze axes. Farrell claimed the book White Power was his "bible". He also insisted to like "foreign cultures".
But, Mr Jessop added: "He then goes on to state 'n*****s are different though because they are subhuman at best'."
The group discussed terrorist killers such as Brenton Tarrant, who murdered 51 people at two mosques in Christchurch, New Zealand in 2019. Farrell stated at one point: "It is about time someone firebombed a synagogue."
The group went on to talk about making firearms using 3D printers. Farrell then shared a video link titled: "The Box Tube MAC-11 - The Ultimate DIY machine pistol".
Mr Jessop said: "The video lasts 75 seconds and shows pictures of instructions on how to build a DIY sub-machine gun. When posting, he states: 'Don't build - share for the music'.
"The video does contain a song about a machine gun and freedom. This is an attempt by Farrell to try and minimize his actions."
The video consisted of 19 images of a document already available online. The court heard "by solely following" the instructions, a non-firing replica sub-machine pistol could be made.
Further alterations - needing "skills and firearms knowledge" - would be needed for it to discharge bullets.
However, Mr Jessop told the court: "Any replica built using these instructions would be intimidating to anyone that was presented with it. It would have a very similar appearance to the machine pistol it is based on."
Farrell remained a member, but his replies eventually became "few and far apart". The Oaken Hearth group was investigated by the North East Counter Terrorism Unit in England.
Mr Jessop: "An undercover officer was able to become part of the group and confirmed the topics of discussion and mindset of all those within."
Five people were arrested on May 1 2021 for terrorist and firearms offences with three being part of Oaken Hearth. The probe also resulted in a mobile phone being seized from one.
The device had chats from Oaken Hearth on it eventually leading to Farrell being identified. In October 2021, his home was then raided under the Terrorism Act.
The same dog and bronze axes spotted in the photo he posted were found in the property. The books as well as other "far right literature" and neo-Nazi flags were seized.
He later admitted to police having had bigoted views. Quizzed about the gun video, he was able to describe it and confirmed he had watched it.
Mr Jessop: "He stated he could not remember where he got it, but possibly saved it onto his phone and shared it. He stated that he had never attempted to make the gun described."
Farrell went on to said the footage was an "edgy, cool video that people might appreciate on that chat".
Tony Lenehan KC, defending, asked for Farrell to remain on bail pointing to a number of factors including him having no previous convictions.
Lord Clark told Farrell the offence was "a serious and indeed a dangerous matter".
He continued bail and adjourned the case for reports until March 9 in Dundee.
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