I think it's the British "Veteran Training: Tank" (veteran_tank_crom in the Attribute Editor). That's basically a copy of the P4/T-34/Panther/Sherman veteran bulletins with the unit type changed, so there's no reason for it not to work.



For how long did you let it fire? The differences will not be very big, and there is some RNG involved. Reload time is between 5,6 and 6 seconds, aim time is 0,125 seconds. Here are some calculations:



Vanilla: 5,8+0,125 = 5,925 sec per shot (~10,13 shots per min)

One bulletin: 5,8*0,95+0,125 = 5,635 sec per shot (~10,65 shots per min)

Two bulletins: 5,8*0,95**2+0,125 = 5,3595 sec per shot (~11,20 shots per min)

Three bulletins: 5,8*0,95**3+0,125 = 5,097775 sec per shot (~11,77 shots per min)



So you have one shot more per minute - with a normalized reload time. It's probably possible and not that unlikely to get 11 shots in a minute with every variant.