No, because literally everone spy checks and the faster firing speed will over rule the reduced damage.

引用自 Dakotastrophy：

+ Crits upon hitting a disguised Spy
+ 50% Faster fring speed
- 50% damage output
- No random crits

-Breaks after 1 hit. Refill at Resupply Cabinet

引用自 Sir Dirty Sanchez The Sexiest：

No, because literally everone spy checks and the faster firing speed will over rule the reduced damage.

How about minicrits and only 25% faster firing speed?

-30% less damage
+40% faster attack
-20% slower building
-20% more metal needed for repairs.
+30% faster movement speed
+When a spy saps one of your buildings, he takes 20 damage.

I'd use it.