After attempting to do so, I have found that it is not possible to convert an 1887 lever action shotgun to a .70-150. The reason is that in order for the action to unlock after firing, it is necessary for the lower part of the breech face to move forward. It does this by pushing the shot shell back into the chamber. A lot of headspace is required in order to provide room for this to happen and it can only be done with a straight case. A .70-150 has a shoulder which would fire form to the chamber and could not be pushed forward by the breech block. It would be impossible to open the action!

You may want to ask this in the Gunsmithing forum, as well.

George

Maybe that is why Winchester NEVER made it a production item.

They onlu built one gun.

Keih

That's too bad, I was looking forward to your finished product and what it was capable of. It would have been a doozy....there are always Ed H's very nice pickin's.

Luck

Coyote Cap sold 87s in 70-150. I assume they
work. Maybe look them up and see what they do.Ed

Perhaps someone associated with Coyote Cap was involved with this. I talked with Coyote Cap personally, and he had not even heard of the 70-150! If someone actually has one that works, they have been awfully quiet about it.
It would interesting to see a picture of an actual winchester 70-150 prototype. I would be willing to bet it is not on a 1887 action. Highwall, perhaps. On the other hand, if it is on an 1887, I would like to think there is a fired round in the proto type!
Anyway, I supose I will sell the shotgun. It is neat in it's own right. As for my investment in pacnor .70 real estate, I have a large martini action, so will likely build the 70-150 on it, in which case, we shall talk again. It would make the mother of all express rifles!

I have often thought of having a 12bore paradoxbarrel fitted on a 1887 Winch.