The weapons sent to Ukraine are generally out of date surplus, and the ammunition for those weapons are generally either out of production or nearly so. The west is no where near going into a wartime economy maximizing production of its latest military equipment, and that is by design. The west has been balancing support for Ukraine against not escalating tension with Russia, who regardless of their conventional military's capability are nevertheless sitting on the world's largest nuclear stockpile. This is a limited proxy conflict, and the west is behaving as such.

> We can barely produce enough weapons and ammunition for Ukraine

Ukraine is fighting a completely different war, with a completely different military doctrine, which requires different type of weapons and ammo. We're rarely sending what we are actually using. The US is not depleting its own ammo warchest to supply Ukraine. For example, the US is not big on artillery shells in general. We prefer rockets.

If the US moves to a wartime economy, I bet it will have a production capacity never before seen in history.

A functional peacetime economy generally doesn't have weapons manufacturing capacity to fight a two front world-war.