Sorry to hear yours is one of the troublesome ones, they do seem to vary in quality control. One of mine I had to strip down the action, boil in water, and give a good soaking in super penetrating oil while hot, that seemed clear most of the problems. It must be remembered it's easier to loosen gun up, then tighten it with a box lock action. I to am loading 405 grain bullets, to what my loading manual tells me will achieve 1600 fps. Still very happy with my 2,and I was interested to read the African experience.
I travel back once a year, and may take mine along this time to see what can be achieved, There will be no dangerous game on the list, "horses for courses" is my experience here.
They are a double rifle, and if people remember what they are, and their limitations (all firearms, in all calibres, have their limitations) they are a a vehicle of tremendous fun and experimentation in loads and regulation.
My problem now is that they are leading me down a very dark path away from the traditional doubles, I am considering building a double rifle on a shot gun action now, I have just ordered a "HOW TOO" book on their construction, and purchased a old TOZ 63, shot gun as the unwilling donor for the action. Nice lock-up, including a Greener cross bolt system, and hammers- a dark path indeed!
Anyway back to this little 45-70, even if a little paid gunsmithing work is needed, they are still a hell of a lot cheaper than their closest rival, and quite natty little game takers, and when I say little I'm referring to the rifle not the size of the game it can take.
Pricedo, I hope the problems with yours are short lived and easily fixed, there will be a little experimentation in loading and regulating, I should say that can be fun, sometimes it can be frustrating! But once everything is tuned in, a great package, and capable of being a serious hunting rifle.
All the best,
600Nitro