What's Involved in Converting an Original Spencer to Shoot Centerfire?

[Major 2]

About 25 years ago, when I first started messing with Spencers , there was an article on conversion of the Original Breach block.
As I recall it involved, diagonal drilling and fitting a shortened Springfield 45-70 firing pin.
We follow the tutorial, but broke a drill bit off in the upper block. Attempt one , sent us back to the drawing board.

Then we developed a handmade firing pin that used the Original Spencer method with a  L shaped mod and milled out a space in the upper block behind so this pin would work ( This is one of the ones used in "The Blue & The Gray ")
About this time S&S developed their conversion upper block , at $ 100 (then) it was a bargain...
the Gun I own now has this block as does the Prop's gun mentioned above...

The S&S Block required just a little adjustment to work smoothly ( the little hole at the bottom of the large pin was stoned )
I still have the original round follower in the magazine ( if I decide to heavily shoot this one Ill get the S&S follower )

[major]

Major231
I don't know if there is anything that is a problem with this but since you obviously know your way around a machine shop.  Why wouldn't it be possible to just adjust the original fowler?  Just chuck it into a lathe and flatten out the nose.  It shouldn't take much.  It would be destroying a piece of history but what else are you going to do with it?

[Major 2]

Funny you should ask ...I looking at just that.

make a hardwood arbor that would fit tight in side the follower, it would have a blunt nose
take the originial fit the arbor inside and chuch & spin it on the lathe using a steel nib to face the shape ...
This is how copper and silver plates are spun, I wonder how hard the steel follower is ?

I might try to get a Original follower spare part and try it....

On camera this was not a problem ( Blanks you know ) btw the blank rounds I made have a soft balsa wood slug.  At 5 feet other than powder burns a paper target shows no penetration, the balsa disintegrates as sawdust ... however it is always handled as if it's live ammo

[geo]

i can't add much to the above but for this one new wrinkle a gunsmith showed me with spencer ammo. if you have difficulty getting the spencer rounds to feed properly (and overall length isn't the problem) round off the top of the rim (the side facing away from the primer side) carefully. my fletcher-bidwell spencer would not feed because the edge of the rim was catching/dragging on the magazine chamber. but do this carefully and it doesn't need a drastic rounding. try a little at a time.