Agreed, I myself have 30 rd mags, but many more 20 round mags. Reason: I load them differently, for different threats, 20’s easier to quickly switch out. One with high quality precision ammo, another with green tip, one with tracer ( you need tracers to identify to your group where a sniper maybe hiding or where to direct your groups fire), a few with ball, but most with hunting, soft point lead ( much much more lethal than ball).
...but of course, my favorite is a Garand for defeating light armor, vehicles and 1” plate steel ( they tend to take away any cover the bad guy may be behind, cars, trees, railroad ties, sandbags, brick walls, ballistic vests, etc..)...surplus .30 cal M2 AP, API, Incendiary is out there, pricey, but it can be found. GB has some occasionally, now running about $2 a round.
Seems to like 73gr Match. Not the penetration, but more stable and a tighter group out to 300. They tend to come apart in soft targets, and that isn't a bad thing...
Like Antifa, I'm out to hurt.