I would choose SN over any other option if I could actually get my hands on it. It has all the qualities of a suicide method that I want: little chance of side effects in the event of failure, ease of administration, and reportedly painless.
Gun ranges typically don't allow people to rent a gun if they come to the range alone. This is a preventative measure for a suicide method that is relatively common.
There is or can be considerable discomfort if not pain with SN and it can take a while to kill you. I have severe anxiety on waiting for effects of substances. There is risk of vomiting. Meanwhile, a gun is near instant and I don't have to fast or worry about keeping stomach contents down. Also, less (no) time to regret and call emergency once the bullet leaves the chamber.
Gun has also always been my dream method, inspired by movies like the Deer Hunter, One Eight Seven, Scent of A Woman, Lethal Weapon 1, Brooklyn's Finest and that Family Guy episode. I also like the thought of having a nice last few drinks and/or low opioid high before going to Hades, which is a no-no with SN.
I would be having the gun as my possession, not in a gun range.
Only concern is that the guy I'm talking to from Telegram drug markets who is selling it, I don't know him and it could be a police setup. That alone is a big part of the equation. He seems to have a reasonable deposit scheme though, so if he is a no-show I wouldn't lose much money. But as of now, SN seems to be the safer option in terms of legality, but damn, the thought of buying a gun and having it ready for any day I can't take it anymore is just so cool. I was already shocked how easy it was still to buy drugs in a country with strict regulations of damn near everything.
Which one can you get easily? That is the best.
If the gun seller is not a cop or a scammer, then basically next week already. With SN I've had problems getting antiemetics rather than the SN. It's a hard decision, because one is hard to get and the other is risky to get.