Here's a 5.7mm against level IIIa armor...
The civilian rounds are stopped. Later in the video you see the armor piercing round. Unless it has a steel core, I doubt 7.62x25mm would do much better. Maybe against level II, but level IIIa.
It seems like the easiest way to improve penetration would be a subcaliber penetrator like VBR technology. Or maybe a some sort of sabot?