Objective lenses?

[kc]

Is it worth it to go with a 40mm Objective lense or a 50mm? does it realy matter?

 

[300grains]

Why not buy both and a 56 mm also. I have them all including 32mm and 20 mm. Smaller ones for daytime, lightweight use and bigger ones for dusk/dawn and bad weather. They all fill their special purposes exactly like to have many calibers depending on what you hunt.
This of course if you don´t use a 375 H&H, then you need only two scopes.

 

[Gene]

In the first 15 minutes of daylight, and again in the last few minutes of dusk, larger objectives are an advantage, because they gather more light. For 90% of your hunting, a smaller objective will be fine.