These "olde" original military muskets where sold off by the government in the early 1900's as surplus arms on the open market.
It was common at the time to just cut a few inches off the worn muzzle, and sold as "reconditioned".
(think Sears mail order catalog, for $5)
Many times they'd be cut back crudely, way back to the middle band, stock included, and sold as a "Sport Musket".
"Stretched" means that member Whitworth has found one and brought it back to original length.
This is a beautiful representation, in remarkable condition.
Well done Mr. Whitworth, is there a "conversion" date stamp on the bottom flat?