tundrus or dark chaingun or your suggestive gun for jk runs

i currently have an avenger, and need a good 3* gun for jelly king runs. tundrus is good because it can freeze, but also considering dark chaingun due to its incredibly powerful charge attack. Please help me choose a good gun for jk runs.

Here is my argument for getting the chaingun.
Nevertheless I'm not a Magnus user so I'm quite biased. I am very aware that both gun types are overall very good either way so as Neo said, it might be best to just pick the one you like the most. Additionally, I'd like to point out that you should sooner or later get a level 10 Strike Needle for Vanaduke. If you do, you might find yourself bored with two autoguns which is a good reason to get a Magnus now and an Autogun later.

Either one is fine. You'll probably end up with Blitz Needle, so maybe Grim Repeater (Dark Chaingun) is too similar. On the other hand, I'm not a big fan of Winter Grave (Tundrus), because its freeze impedes its charge attack damage.
Have you considered Umbra Driver (Shadowtech Alchemer)? That's the other style of big-charge gun.
Have you considered Acheron (Nightblade)? That's another of the most powerful weapons in the game. You can do all of Royal Jelly Palace with just that (although a non-shadow weapon is nice against the silkwings).

im told that the dark chaingun can charge shot rjk 3 times and he dies. but tundrus is good crowd control. autoguns also leave the player vulnerable.
i have the 2* shadowtech alchemer. also have nightblade 3*.

but tundrus is good crowd control.
I'll say they both has around the same rank as far crowd control goes. Chaingun also has slightly knock back effect.
autoguns also leave the player vulnerable...
not necessarily, you could anticipate monsters attack, move yourself in a good position (the attack won't reached), and release charge.
shadowtech alchemer is more like heavy damage one target thing.

They're both pretty equal in terms of JK. It really depends on personal preference.
I got a needle shot, didn't like it, so I got a tundrus, which I did like.

There is no rule saying you have to get only one.... get both

thanks guys, ill get both, but ?? first, they are both in the 20k cr range at the AH. And thats a lot of grinding.
Do Tier2 clockworks runs and hit up Basil at depth 13, get the recipes yourself.
Run it in the Roarmulous Twins gate and get some Bark Tokens and advanced/elite alchemy orbs while you are at it.

If you want to get one first, I could suggest getting the Dark Chaingun first.
Both have the same level of crowd control, but the issue with Tundrus is the sporadic freeze on the charge, whilst the chaingun is slightly more reliable due to the knockback effect on it.
Another point is damage; both are great at what they do, but Tundrus falls again due to the freeze on the charge (you can either freeze at the charge's end and do full damage, as you can also freeze them at the first hit and entirely waste the charge), dark chaingun being alot more reliable and more neutral due to the lack of status effect and natural high dps.
All in all, Tundrus is hella fun, but between them and the Chaingun, the Chaingun is a bit more practical for what's weak to it.
That's just my opinion, of course.
Both of them are good, pick what you are more comfortable with.
If you know how each weapon works you should be able to make a decision.
I personally favour autoguns over magnuses, due to THE most dmg they can do in one charge in the game.