I'm wondering how Psilencers vs Psycannons compare against different troops or vehicles when upgraded...
24 Str 5 AP-1 shots doing d3 damage each or,
16 Str 8 AP-2 shots doing 1 damage each.
I feel like one is meant for hoards and the other is meant for heavy support, but with that d3 I just don't know!
So, I've tried some Mathammer on this. For each comparison, I've shown the standard effect followed by the effect with the stratagem active. All are calculated for a single model firing.
Against Guard (T3, 5+):
Psycannon: 1.39 > 1.67 kills
Psilencer: 1.33 > 1.67 kills
Against marines (T4, 3+):
Psycannon: 0.67 > 1.11 kills
Psilencer: 0.5 > 1.00 kills
For two wound models, I've used a conversion factor of 0.5 kills/unsaved wounding hit for the psycannon (I.e. You need to get two unsaved wounding hits to kill) and 0.75 for the Psilencer (as one in three unsaved wounds will need a second to kill).
Primaris Marines (T4, 3+, 2W):
Psycannon: 0.33 > 0.55 kills
Psilencer: 0.38 > 0.75 kills
Terminators (T4, 2+, 2W):
Psycannon: 0.22 > 0.42 kills
Psilencer: 0.19 > 0.5 kills
Leman Russ (T8, 3+):
Psycannon: 0.33 > 0.67 wounds
Psilencer: 0.33 > 1.00 wounds
(N.B. These are calculated assuming that the model moved and that the target doesn't have a cover save.)
So, although the psycannon clearly has the edge for getting wounds through, the psilencer's Dd3 often gives it the edge against muti-wound targets. The stratagem does give the psilencer quite a bit of help against terminators and Leman Russes.
Against T3 models, the stratagem doesn't actually affect the wound rolls, although the AP-1 helps still. (However, whether using 2CP to kill 6 guardsmen instead of 5 is worth it is a question I'll leave you to ponder...)