You might as well compare a Luger to a Beretta M9, or even an MP5, because the rounds are so similar, right?
It's not even a close comparison, sorry!

One was an added option to boost firepower on a Zerstorer aircraft, hunting down bombers. The other literally had the entire airplane designed AROUND it, taking up most of the internal framework of the airplane itself, and is to date the most feared anti-tank platform in the skies.
So, yeah.... They're both 30mm so they're the same. Okay. (Sarcasm! alert! sarcasm! alert!)
[Edit: Sorry if the above is "too much" but.... somebody had to say it! Back to the Me410 BK5 discussion!)