OK, so there's been a moan about no new posts, so here's one.
I bought an 1885 Winchester Low Wall .22lr made in 1906. While it's not a particularly pristine example, it is unbelievably cute. The trouble is, it doesn't seem to be much of a shooter. Hardly surprising when the rifle is about as old as I feel in the morning these days. I have a 1920s Greener small frame Martini rifle, also in .22 lr which has at some time in it's life been 'Parker Rifled', which is to say it has had the barrel bored out and a rifled tube inserted. These were often said to be more accurate than the original and was considered to be a cheap way of improving a worn rifle. This Greener is certainly acceptably accurate even though the Parker Tube was probably fitted over half a century ago.
OK, that sounds like a workable solution so I start phoning gunsmiths. Not one expressed any interest in doing this, several saying 'no' by quoting a starting price of at least £1,000! As I start digging in to the matter I am rewarded by finding a PDF file linked by Brownells no less on how to perform this miracle of engineering. You need the rifled tube, of course, a piloted drill to suit bore and length, which Brownells conveniently supply, a chamber reamer, a few basic tools, some accraglass (sp?) and, would you believe, a hand held power drill. Oh! Nearly forgot, a padded bench vice. (There is a Youtube video of a bloke doing a re-tube but he's dead posh and uses a lathe)
Basically, you remove the barrel from the action, if you can't get at it all the way through from both ends. Put the barrel in the vice. Take the piloted drill and carefully start on one end of the barrel using your handheld power drill, variable speed preferred (!). The pilot follows the original bore, keeping things straight. The drill goes just over halfway down the barrel. You then turn the barrel round and drill from the other end. Because the pilot drill is still following the original bore, everything lines up nicely. Once through, you clean it up a bit, and fit the tube using accraglass to bond it in place. Then you trim the front and re-crown, trim the back and ream a new chamber (That's the tricky bit I bet) and Robert is your mother's brother. Getting hold of rifled tubes might be a bit of a job, as at first glance they seem to exist now only in the USA, who place export restrictions on such weapons of mass destruction to about the only country in the world that speaks to them voluntarily any more.
If I could get the tube I'd be tempted to give it a go myself, apart from the chamber reaming bit.