So lately I've been pulling Dynamis as COR and it has worked out pretty good. I would highly recommend it if you get bored with the old roll/sleep/cure routine most of get put into during Dynamis because we are in the BLM pt.
What You Will Need
1. Powder Boots: These are pretty much essential for pulling in Dynamis. You will use them at least once or twice a run and are extremely useful for other various tasks in Dynamis. They are also very cheap and the cool down timer is very low. I always have a pair on Char at all times.
2. Gun: Now there are of course a couple paths you can take on this. Your options are Martial, Peacemaker, Quicksilver/other hexagun.
Martial Gun: Your Martial Gun has the longest delay out of all 3 guns but also will give you the boost in WS/QD damage when you use those. I prefer my Martial Gun over a peacemaker because I know its delay and can make any pull with it, plus mine has +8racc on it.
Peacemaker: With this gun your getting the speed which is nice and a boost to QD acc with the agil. You will loose out on some QD damage but its easier to pull those tricky pulls.
Quicksilver/Hexagun These guns are basically the middle man between your Martial and Peacemaker. They are perfectly fine for pulling and with the Fey gun you can possible get a nice -delay on it.
3. Subjob: Just like your gun you have a couple options. I have pulled Dynamis on all 3 of these and all worked well, just depend son the zone and your groups ability.
/nin: Pretty much the default sub for DDs/puller in Dyna. Its nice for lasting through a couple hits when you have pulled mobs at camp and waiting on sleepgas or to absorb spells like Bio or aoe moves such as sweep. I generally default to this sub unless we have a high number of RDMs.
/thf: lolth1, ok I said it, but it can make a difference. Not all Dyna shells have TH4 so every bit of TH helps. As a COR you will be poking almost all mobs and stats so its not hard to get on the hate list and spread that TH around on top of your THFs TH. You also benefit from /thf with steal (hello free coins) and flee. I tend to use this on easier zones such as Bastok/Sandy/Glacier due to lack of AOE's, plus you wont need to burn up your powder boots.
/rdm & /whm: Both of these are nice as it gives you the ability to cure your self and others and contribute even more to the group. You also get stoneskin and blink which is generally enough to make it through any kind of bad pull. Cap that off with MAB bonus form /rdm and your QDs will be boosted a bit more.
Thats really there all is to it. I know a lot of shells only let RDM/PLD/THFs pull but the more I do this on COR the more fun it becomes. Its extremely easy to keep your BLMS buffed up while your at pulling and you can still sleep things.
My ls generally has our THF follow me out on pulls and tags all the stones and then he goes back to meleeing mobs, which allows for more TH on more mobs. I encourage you guys to try it out, as it will liven your dynamis experience up a lot.