which brand of drum magazine is the most reliable

Magpul. Don’t waste your money on anything else.

Magpul. I only own 60 rd drums though, no experience with the 100 rd - yet.

Thanks

I do not have any drums but the Surefire 60 and 100 round mags work perfectly.

I bought the cheapo Asian made two drum 100 round magazine a few years back. It was the one that required graphite lubricant. That thing failed spectacularly after its third 'mag dump'. It went from my AR ejecting quarters on the ground to me trying to pick up pieces of dollar bills real fast.