Yes, Winchester did that with BLACK POWDER. BP is basically self-limiting. No matter how much BP you put in a gun it can only generate a certain amount of pressure. Try that same experiment in a 76 with smokeless and see what happens. As far as the hammer spring holding the bolt shut have you tried it? That is baloney. With even light smokeless loads and both links in the rifle if the links are even slightly out of alignment you are going to get a pretty decent smack on your knuckles when the round, BP or smokeless, goes off. Been there done that. With no links you've got a straight blow-back condition. Even half a cocktail won't make your forehead feel any better when the bolt assembly hits you between the eyes. I too have shot lots of light smokeless rounds out of original 73s. However, let's not put stuff on the wire that can get somebody killed. (Oh, when I am using the word "you" I do not mean any particular person. Just the generic "you.")
Au contraire. "Self limiting pressure" is a myth according to those who know more than I :
(pp. 194, right column) https://books.google.com/books?id=Dzxyneq43AEC&pg=PA194&lpg=PA194&dq=black+powder+100,000&source=bl&ots=6jk5VfyhtX&sig=W07prIcKydA6ca-sXKlQaYtRBew&hl=en&sa=X&ved=0ahUKEwiju7zl25nOAhUE3WMKHfqGADgQ6AEIKzAC#v=onepage&q=black%20powder%20100%2C000&f=false
(pp. 34 left column)https://books.google.com/books?id=OF7WL7hIhA0C&pg=PA34&lpg=PA34&dq=black+powder+100,000&source=bl&ots=mTlmn7ZiKp&sig=12ql2rGrTiMuZXh-2LKfWJeCs60&hl=en&sa=X&ved=0ahUKEwiju7zl25nOAhUE3WMKHfqGADgQ6AEILjAD#v=onepage&q=black%20powder%20100%2C000&f=false
(par. 14) http://www.chuckhawks.com/blackpowder_pyrodex.htm
Why are different grades of BP? If it were self-limiting in regards to pressure, we could just pour cartridge cases full of 4f and be merrily on our way. Right?
I've read the account of Winchesters attempt to destroy the toggle link 1876 (I'll try to find and post it as its very interesting) and they did so by driving additional bullets down the bore.
I didn't say the hammer spring would hold the bold closed
rather it seems conceivable that tension from the hammer spring could limit the rearward travel, or velocity, of the bolt. But then, that's the subject of case head thrust, not chamber pressure. Once the fired cartridge case clears the chamber or the buet clearn the muzzle, whichever occurs first, there is no more pressure.
This is not "the wire", it's the CAS forum
No one is suggesting dangerous loads or practices. If smokeless loads are dangerous in these old rifles, why have ammunition manufacturers been loading them and folks using them for nigh on 100 years?