No. The Circlip guns apart from being ugly with those clips, are not recommended for conversion to centerfire cartridges. The action is a shotgun action and should remain a shotgun.

Look around for a commercial Martini Henry action and build on that.

Or as an alternative contact IMA in the U.S. and have them send you an untouched Mk II http://www.ima-usa.com/militaria/origina...-untouched.html

Use the action to build your rifle.