Van, I had a Shaver 22 adapter for my 40/65 Shiloh and it was very accurate.  Two problems though with Lee's adapter, the 22 cartridge was a pain in the neck to load after placed in the 40/65 dummy case and I got 15% to 20% misfires.  A gunsmith friend re-shaped the 22 firing pin and cut the misfires down to 10% but I finally gave up and bought a C Sharps model 75 in 22LR.  Great gun!

Rich

At the nationals there is someone who shoots a Crossno liner in a #1 roller chambered for 45-70(90?) and generally is top-10. He was the winner two years ago. They seem to shoot pretty well.

Same as been said Van.  I use one often for offhand practice in my back yard.
100M range and a bank of 5 chickens.  Accurate as anything else I own.
Well worth the money.  I highly recommend them to anyone who wants use their large bore for practice using 22 ammo.
By the way, I have shoot a 3/4", 3 shot group, (typical group would be 1" (+/-) @ 100m with target ammo before using my mva iron sights. This for me is plenty good for silhouette. 
They will 'shoot'.

Cary

fwiw: I have been told that the Crossno and Shaver 22 rf adapters use to differeing systems and approaches.  I have owned and shot a Shaver version and it worked well, like most 22rf, better with some ammo than others.  It uses (I believe) a modified 22 barrel liner thats held centered on the bore with some sort of durable foam plugs the chamber end has an adjustable nut for headspace.  The 22 rf round is placed in an adapter that is shaped and sized to fit the base section of the 45-70 family cartridges. It has an internal 22 rf firing pin which is struck by the rifles hammer.  Working the action extracts the adapter with its fired 22 rf case using the regular rifles extractor/ejector.  With the right ammo mine was very accurate.

If my information/recollection is correct the Crossno adapter uses more of a one-piece barrel and chamber with the chamber end machined a little off center so the rifles firing pin hits the rim of the rimfire----I do not know how the ejector/extractor work.

Both are accurate by all reports, but I imagine there may be a cost availability difference

Rich,

How difficult is it to load the C. Sharps? I've been considering one but was concerned about manuvering the round into the breech.

SS

I shoot a Crossno liner in my Sharps - super easy to load, but extracting requires flipping the fired case out with a screwdriver that comes with the liner. Mine came so loose that it would just drop in my gun, and as a result had no accuracy. Called Crossno and told them the delrin adapter was cut too small, and they wanted me to send the whole thing back. Instead, I had a buddy cut several new ones on his lathe. I also bought a length of shrink tubing to beef up the liner for a tight fit like it should be. It shoots MOA now and is very fun to shoot in the long range .22 match.

I use them in my 40-82 & 45-90 Hepburns, they work fine. Actually I have 2 liners for the 45-90, one is typical 1-16 twist and the other is a 1-14" twist liner (a TJ special order liner), both are MOA accurate.