Hi Phil,
I'm not sure if some people read too much into the 5.5 / 5.6 mm calibre and pellet comparison. I have found that 5.5 mm Hobby and FTT pellets generally work in most 5.6 mm British bores that I own, often better than the old 'proper' Wasps we all remember with rose tinted specs. One exception is an early BSA Improved Model D I own that only seems to like 5.6 mm Marksman and groups like a shotgun with anything else.
Kind regards,
John
Currently looking for Baikal Makarov pistols with the following prefixes to the serial number: 98, T01, T09, T21, T22
Prefer boxed or cased but will consider loose examples too.