As bubba stated, you have to keep the vent holes covered in wet, damp weather.
Only load that would shoot reliably in mine was good old black powder and CCI #11 magnum caps.
Hunted with a Scout for over a dozen years and that was the only load that went bang everytime
under all hunting conditions.
At the range(summer) it would shoot any powder, under hunting conditions it was a different gun.
I just tired of having to completely tear the gun down to clean it.
Good shooting, TC