Well I have now fired some of the new Woodleigh Hydrstatic bullets through one of my doubles (a very old WR 500/465) and no problems. They also kill damn well !!!

I would have no problems using them Woodleigh Hydrostatic in any of my doubles.

Had a close look at the shanks of the bullets after recovery
and Woodleigh have got it right in terms of bands engage the rifling but the main part of the bullet doesn't.