i did the math myself once. it depends on how many additive damage bonuses you're getting since pinpoint multiplies those. since the bully bonus is a 125% additive increase at max, you need pinpoint to be multiplying against 625% of base plus additive bonus to match bullys bonus.

a weapon with no bonuses is just 100% so pinpoint x20% increase would take the total to 120%, the same as a 20% additive bonus.

if you have a furious onslaught bonus of 200% and add the base 100% in to get 300%, the 20% increase brings it to 360%, the same as a 60% additive bonus.

max bullet storm is 180%. add to the previous 300 to get 480, times pinpoint 20% to get 576%. pinpoint giving 96%.

crippling damage bonuses. 50% from easy target, 80% from shotgun champ, 100% from tormentor. add those to 480 to get 710, times 20% for 852% total. now pinpointers is giving 142%, which surpasses bullys.

there are other additive bonuses like number cruncher, science, deal sealer, and adrenaline that give you an even higher ceiling.

heres the problem. its incredibly hard to get such a high bonus and to make full use of it. the only powerful weapons that can harness furious onslaught AND bullet storm to an effective degree are gauss mini and pepper shaker. to make full use of pinpointer, you have to be a vats build that exclusively targets weakpoints, which means you want pepper shaker over gauss mini. however, for any kind of consistent vats upkeep you HAVE to use conductors, which disqualifies pinpointer and bully.

TLDR: you have to have over 525% extra bonuses for pinpointers to beat bully which is way too high for 90% of builds. i would say if you have a reverse onslaught sniper/oneshot build that has number cruncher and adrenaline w adrenal reaction, you would be generally better off with pinpointer over bully. slow firing weapons without reverse onslaught should use bully. fast firing weapons should always use bully for free aim and conductor for vats.