I'd never part with my. 177 hw100,
You could only equal how accurate these are, never better.
The impact was designed to be an fac tool, I would never get one in sub12, a lot of £ to shoot something restricted to the hilt in sub 12. An hw with the anti tamper removed is as adjustable as the impact sub 12
In fac format though, the impact is so many guns in one. Clinical accurate once set up. Record the settings.
After that if i want I can turn a sub moa 54fpe .25 beast into a barn Ratter spitting 25.4 jsbs at 600fps