In the text is the caveat:
"Caution: DO NOT modify the Trigger Spring without also modifying the Hammer Spring as described."  Why not?  I've installed lighter trigger springs from Brownell's in my duty ARs but, not wanting to risk a light primer hit and a misfire, have left the the original Bushmaster hammer springs in. Is this a problem?  What is the effect?  Why the warning?
Thanks for any enlightenment.

With a full strength hammer spring, and rough, gritty sear surfaces, and a lightened trigger spring, there is the possibility that when you take up slack on the trigger to the point just before the hammer is released, that if you decided to not shoot, the trigger would not return to full engagement, instead, hanging right there.  This is why my advise was to do any lightening of springs first to the hammer spring.  Then, additional lightening is obtained  by modifying the trigger spring.

AH! It all becomes clear.  Thanks for the reply.
I installed the lighter hammer spring in my V-Match but was hesitant to do so on my duty rifles.  Guess I'll change 'em out as well (have'nt experienced any FTFs on the V-Match)

Thanks again,