I'd rule that gyrojet rounds have to be upgraded as grenades/rockets/missiles instead of as normal balistics so no, high powered wouldn't work for them.
And to the previous poster oh, so long ago... yes. I've played a runner that used gyrojets in regular combat. It involved a lot of positioning and always modding my guns with bayonets. All my other characters tend to eventually get one as well, but only for specific environments such as space.