If your M1917 Enfield has flat bottom metal, it's been altered. Remington Enfields had six round magazines just like all the rest.

A Remington Enfield can be made into any .30-'06 length caliber or any short magnum. If you want a little more oompf from your rifle, you might consider rechambering to the .300 Winchester Magnum or the .308 Norma Magnum. The latter would give you more room in the magazine to seat the bullet out, increasing the case capacity.

If you could locate a P-14 bolt, you could avoid having to alter the original .30-'06 bolt face. You also might want to add a Dayton Traister cock on opening conversion.