I love my March FX 4.5-28x52, I think it's a really good piece of kit. That being said, March has a number of other optics that are arguably MUCH more suited for what you're trying to do. The FX is a "crossover" or hybrid scope that leans heavily towards that field/tactical shooting genre. If you're dedicated to BR or F-class, the D60HV56T for example (the "High Master" 10-60x56).
Again, I love my FX... but, if you walk the line at BR and F-class matches, you're not gonna see many (any?)...