I find the sword-like 1917 bayonet - used on P14 and P17 Enfields, all AEF 12 gauge "trench guns," and Winchester 1897 and Model 12 World War II "trench guns" - to be much too long.

The better alternative is to identify a standard bayonet for for another rifle that fits the World War I-era bayonet mounts.

Internet searches for such a "better" alternative have so far been unsuccessful. I may have missed the solution. A solution may require only alight alteration of bayonet "xyz's" mount guard to have it fit the 1917 bayonet lug assembly. I do not have access to a bunch of different bayonets to verify either way - or to find out whether futzing with bayonet's mount will allow it to fit the 1917 lug assemblies. And Internet information consists of: "Yes, bayonet will fit a lug assembly" and "No, bayonet will not fit."

The inferior alternative is to cut off a reproduction bayonet's blade to length that is wanted, then use grinding wheel, with bucket of water to cool metal, and recreate blade's basic shape, albeit shorter.
***
"Why?" you might reasonably ask. I recently acquired a heat shield with bayonet lug for my Winchester 1897 shotgun. Having affixed the bayonet, the beautifully compact trench shotgun becomes as unwieldy as a Swiss Reisläufer's pike. I am more interested in "comfortable" than "period correct." Having typed that, yes, I will keep an authentic 1917 bayonet when I want the trench gun to be "period correct."
***
If you know of a shortened 1917 bayonet, or a different bayonet that fits a 1917 lug assembly, or have available a different bayonet that has been altered to fit 1917's lug assembly, please let me know.

If you can shorten a reproduction 1917 bayonet, or know someone who can do it, again, please let me know.