Considering how the yari animation looks...I'm afraid it would look a bit ridiculous with a rifle.
well, no one knows for sure until it`s been tried.
i could live with a decapitation through bayonet..... i think.
when considering the history, starting in the 18th century "sword bayonets" where mainly used.
link:
these bayonets had a size of of quote: "58 centimetre (23 inch)" and where puposed for infantry fights against cavalry.
and also considering the rifle size (from wiki)
In 1886, the French Army introduced a 52 cm (20 in.)-long quadrangular
épée spike for the bayonet of the
Lebel Model 1886 rifle, the
Épée-Baïonnette Modèle 1886, resulting in a rifle and bayonet with an overall length of six feet (1.83 m).
so when thinking that the yari animations would be problematice because of the larger size of the yari compared with the rifle, there might be an excuse for just enlaring the size of rifle and bayonet to 1.83m.
(and yeah i know that 1886 is not 1868)
if no one wants to try and if there is a toturial on how to change animations and weapons skins here, please show me the link, and i`ll try it