Hi

I have tried the "soft jaws" that you can buy from B&Q but found them too abrasive on the blueing on the barrel.

I could not find a suitable way of holding my underlever with them either since they allowed movement when cocking.
The only answer I have found is to buy a second hand guns smiths tray off E-bay. I got mine very cheap (£30.00) and it does a brilliant job and is usefull for other things as well as just setting the scope.

Hope this ramble helps someone.