I rechambered the HMR I had, took it out a few times but, never saw anything to draw blood with it.
I don't recommend this .17x28mm based on the 5.7 case because of brass being so hard to find. But, that's what I made this one into. It's supposed to be a great shooter once it's finished.
But, I filed too much off the extractor and can't locate a new one. H&R wants the barrel sent so they can 'machine fit' it. You know what they'd do about that customized barrel if they'd get hold of it. Right Tim?
On this one I used the rimfire barrel, and action from a .410 to get the centerfire. Fit was perfect, didn't have to touch it up at all.
Trotter rechambered one for a .223 I think, and maybe a hornet sometime back. Was real happy with it. Might be good if you'd read the sticky's, whole lotta ideas and info there.
Wish you well,
George