Each projectile needs to update itself. I’m using projectile movement component (PMC) at the moment.
To properly test the pooled method you need to do long range shots where the projectile exists for long durations of time, thus long simulation times. The more you have being simulated, the more processing power you eat.
Also note that when you test multiplayer in PIE your doing double duty. 2 players equals 3 simulations on the same shot that your PC is doing. Shooters processing + Sims processing + Servers processing… for each shot fired.
Here’s a reply that goes into more detail of an older variant of my process.