How about the Masterlock Python ?

Ideal for trigger guards as they don't have any end loops,
the cable goes in to the lock to form an endless loop,
you can join several together or have one long cable, they come in various lengths up to about 30ft & 5,8,10mm dia
I've got several for securing trail cameras, amongst other things.

https://www.amazon.co.uk/Master-Lock...49&sr=8-8&th=1

Better still are gun cabinets.