I was reading an article that stated that a certain weapon "necessitated the need for" more training. To me, this sounds incorrect, as "to necessitate" means "to cause something to be needed" (Cambridge dictionary); therefore, following it with "the need for" is redundant. However, I can find nothing to confirm this, and a Google search for "necessitate the need" comes back with many examples of published works and scholarly articles that use the phrase. Am I being overly pedantic?
No, you are not being pedantic in the least.
Let's say "A growth in population necessitates the need for more houses".
How is the meaning any different from "A growth in population necessitates more houses".
Or how about "A need for more houses will arise from an increase in population".
I suppose a need for something could be a necessary requirement to some purpose or other. For example the investment in a new machine by a manufacturer of widgets necessitates a need for a greater demand for widgets.
But this sort of semantic gymnastic is unlikely to serve any practical purpose. So for the most part the use of necessitate in juxtaposition with need is duplicatory.
It's not incorrect because need is followed by 'for', which states that there is a need for y. Necessitated means to make (something) necessary as a result or consequence. 'Need for y' is that 'something' which was made necessary, in this case.
Or maybe you need to share the complete sentence for analysing the context.