[a guy that can]

Thanks guys but reread the post. I don't have the resources or time to find out for myself.
I'v read about the 300 whisper projects and that is not what this is about, It can and would be preferred powerful.
Its about OAL. (over all length)
Against my will apparently the reason behind this needs to be explained.
I was inspired by the GunWebsites Youtube video with the bond arms CA legal derringer and before you roll your eye's and logoff let me explain.
It was ridiculous yes but it had a point, you could see it was loaded!
I looked and looked for a rifle bullet that could fit a short barreled derringer.
32 H&R was the only one I could find with a rifle bullet (303 Brit) that could fit.
The 327 fed isn't chambered in any derringer I can find but your right some one could trim it and it would handle pressures better.
So unless you know a better readily available, long, non-cast bullet then I'm sticking with the Idea.