gaugedrifles:

Also note the significant "step" in the profile of the barrels just in front of the chambers. This would indicate that these were sleeved rather than lined, as the barrels in front of the chambers are no longer their original diameter. This "step" is about where the other seam would be if the conversion was done via sleeving rather than lining.

Hmm. The link to the photos has now disappeared and the second and third photos are no longer available.

"Serious rifles have two barrels, everything else just burns gunpowder."