You need to research what is legal in Northern Ireland.
General info, remember to check dates, laws change:
https://bushcraftuk.com/snaring-law-uk/
https://bushcraftuk.com/trapping-and-the-law/
https://www.gwct.org.uk/advisory/guides/fox-snaring-guidelines/legalities-of-snaring/
http://www.legislation.gov.uk/ukpga/1981/69/contents
https://www.pestmagazine.co.uk/medi...tice-for-use-of-vertebrate-traps-sep-2014.pdf
Interesting that there is an anti-snaring campaign, so it would be best to know your stuff.
https://www.antisnaring.org.uk/laws/defra-code-of-practice-on-the-use-of-snares/
I have been told by people who have researched this stuff, that you cannot legally use anything other than free running multi-strand wire cable snares, live catch traps (box or cage) or approved manufactured steel spring traps. Dead falls, pole snares, spring ups (sapling powered), basically any mechanical snare that is not live catch or commercial manufactured is illegal.
Having said that, in the 15 minutes I have been digging around, I have not found actual legislation that spells out, for instance, that you must use multi-strand wire for rabbits, or that primitive deadfalls are illegal. However that does not mean it is not there since there are a ton of overlapping statutes, and some things may be implied. Careful reading needed.
A lot of the primitive traps can be rather indiscriminate, not a problem in the wilderness when you just want food, but not good in areas where many animals are protected, or domestic.
As a question of bushcraft, well, actually the brass wire rabbit snare is hard to improve upon. Trapping is a numbers game and simple snares are quick to set and easy to move where needed. Rabbits run from open grass areas to burrows and in our arable/pastoral landscape there are often very few places that one can set bent pole string snares, or have enough big rocks and logs for dead falls. Using a log for a drag anchor is more efficient than spending time making it into an effective dead fall.
ATB
Chris