TL;DR
- If you want to maximize the damage output over one Blast, use Slinger Ammo Secret and attack fiercely.
- Surprisingly, Charged Shelling has the highest "shelling" damage for both Wide and Long. However, I suggest using ordinary Shelling for Wide because well, charged shot literally kills the reason to use Wide, and my experiment completely ignores poking damage. Full Burst loop, on the contrary, is the strongest in overall damage-wise and in shelling damage-wise for Normal weapons.
About "exhausting" the Blast
Wyrmstake Blast is timed. This means that no matter how you attack, i.e., whether you do not shell at all or shell as much possible, does not affect how long does it takes for a Blast exhausts.
The only factor that affects the fixed duration is the type of the Slinger ammo, and the currently loaded number of Slingers. Therefore, picking up the pristine slinger and then immediately loading it is the only way to maximize the duration of the Blast when all the skills are the same. Slinger Capacity and Slinger Ammo Secret will increase this number, though, and allow you to use the Blast for a longer time. This video I recorded for this question accounts some of them.
Irrelevant, but if the Blast is about to disperse, it will emit some smoke, and some time later, it will disappear.
Okay, so, how can I maximize the damage?
Well then, somebody already did the shelling test for vanilla World, and on top of those numbers, we just have to add how Wyrmstake Blast interacts with the base damage. Unfortunately, I had to measure the charged blasts myself, because they did not do the charged blast for non-Wides.
It seems how the Blast increases the shelling damage is not uniform, and instead the rate changes as the weapons' Shelling Level progresses. Therefore, I am assuming the highest Shelling capability from now on by the following weapons with Load Up:
- Normal: Stygian Avaritia's Lv7
- Long: Deathlance Vaal Spysa and many others Lv6
- Wide: Royal Guard Striker and Rajang's Lv6
Also, I will be completely disregarding the slashing damage for now, because that does not interact with Wyrmstake Blast at all.
Time values given below are derived from my own experience, If there is only the DPS, I borrowed TheGameeconomist's time data and divided the new damage values by that.
Combos of Wide weapons
- Poke-Shelling: Shelling 85, Blast 40 = 125 per shelling. DPS: 71.29
- Full Burst: Shelling 77, Blast 66 = 143(!!) per shell. DPS: 83.13
- Charged Shelling: Shelling 117, Blast 120 = 237 per shell. DPS: 237 × 3 ÷ 6.05 = 117.52
Combos of Normal weapons
- Poke-Shelling: Shelling 51, Blast 30 = 81 per shelling. DPS: 56.56
- Full Burst: Shelling 61, Blast 50 = 111 per shell. DPS: 129.07
- Charged Shelling: Shelling 80, Blast 90 = 170 per shell. DPS: 6 × 237 ÷ 11.93s = 119.16
Combos of Long weapons
- Poke-Shelling: Shelling 71, Blast 35 = 106 per shell. DPS: 81.07
- Full Burst: Shelling 71, Blast 58 = 129 per shell. DPS: 100.00
- Charged Shelling: Shelling 158, Blast 105 = 263 per shell. DPS: 171.61
Conclusion
Shelling-wise, going for charged shot is strongest shelling-wise except for Full Burst weapons. However, since charged shots completely disregard the poking damage, I would rather go for standard poke-shelling for a wide weapon.
Normals can just stick for Full Burst, except for some exceptional cases like Wyvern's Fire.
Oh, and do not bother about ordinary Wyrmstake. Although the exact figure is not given above, I think the damage matches one shot of a Charged Blast; not worth the time.