Yes, the '40 is plenty accurate for 10m competitions right out of the box without any mods. If you click on the UBC link in my sig, have a look at the last few months' 10m competition results, and in particular the SSP category.
You'll see some very respectable 10m scores posted using HW40s, Gamo Compacts and Webley Alectos - all reasonably-priced guns and even more so second hand.
Hope that helps, and I hope to see you taking part in the comps when your project is complete.