I think they’ll both be exactly the same difficulty to stop due to conservation of energy. If the spring used is the same for both the bowling ball and the marble, the bowling ball is going to be going much, much slower than the marble.
I think that spring still leaves ambiguity. A very thick, powerful spring like that in an ejection seat could probably get the bowling ball airborne, but wouldn't actually impart anywhere near the same amount of energy on the marble.
A small elastic band like that used in a slingshot on the other hand would have difficulty getting the bowling ball to fly at all but could turn the marble into a bullet.
I mean, you cold just shove the marbles down your throat, but failing that... I know what it's like to hope that someone pummels you to death with a bowling ball. I hope you don't genuinely feel that way, but if you do, there are people here - myself included - who would be happy to offer advice to try and not feel that way, or at least provide some temporary relief from that feeling.
And that goes to anyone else reading this who feels that way: no matter where you are in your head, there's a way out of the darkness. Take it from someone who's been there ❤️
I'm not a Physicist but since they have the same momentum, the marble will have a higher velocity. Let us assume the bowling ball weighs 6000 gm and the marble weighs 20 gm (average weight), the velocity ratio of the marble to bowling ball is 300:1 (300 times faster).
If we assume that both of them are made of the same material, and you throw the bowling ball at 1 m/s, then the marble is launched at nearly Mach 1. I'm pretty sure it will create a neat hole in the bowling ball.