It was an egregious problem with 3.x MCH especially, which got made way better in Stormblood in my opinion. When Reload moved down to 30s recast instead of 60 and Quick Reload to 15s instead of 30 (which is huge), it literally changed the very feeling of it. Granted, Reload gave only 3 ammo instead of 5 like in HW, but with the 5 you also had to overwrite procs in the first place since the max was 3 not to overwrite anything.

HW: 7 ammo every 60s, meaning 30% of your GCDs benefitting from ammo use, but when taking ammo overwriting into account it went down to a dreary 20%.
SB: 10 ammo every 60s, which brought this up to 40ish %. On top of it it was a lot more spread since 4 of those came out of quick reloads, one every 6 GCDs. It was a good system that actually prevented to spamm fish for procs, unlike HW during mildfires (the ones not aligned with Reload). Reload was always here for every wildfire and didn't make them peter out due to huge rng luck, but granted a good welfare of base procs to work on even if you entered WF with little of them.