I have been shooting my .22 Mk3 quite a bit lately, and with practice I believe it could well be. I have tried a few different pellets, and found that Milbro TR are surprisingly good in it. At the moment I am finding my .22 Longbow more accurate but it's scoped, I am sure that if I persevere with the open sights on the Mk3 it will put in decent groups!

Loads of people have hunted successfully with Webley Mk3s in the past! I would say that, give a good lube job with modern lubricants and a new spring, they can develop 10.5, maybe 11 foot/pounds if you're lucky.