More strum and drang, very little of actual fact. Depending on exactly what weapons system things can be anywhere from only a little redirection of production and minor increase in production can provide, to it will take 5 years to go from one had built example per year to series production of several a month.
Note, sustained increased production requires increases in inputs. The bottle neck can then be at any point in the production chain from raw ores (or crude oil, or farm produce etc) to final assembly of the finished product. For an in depth example of a basic finished product I suggest the essay “I, Pencil”.
I doubt that the only bottle neck is in machine tools, it is likely also in people who can use those tools well. Training even semi-skilled workers often takes weeks. Some of the processes at key points of the production chain are not easy to start or stop. Famously one of the common types of steels production works best as a continuous process, if you are making steel by that method the only way to increase production is to effectively build a new plant.
Above all, what strikes me as unbelievable is the apparent utter lack of planning: any bottlenecks should already be known as well as ways of mitigating or preparing for them. But instead we get a deer in the headlights look from DOD despite $1 trillion in defense spending.