If you are interested only in performance rather than the benefits of the .300 H&H in reliable feeding, which is not all that significant, you can take any .30-'06 bolt action and have it rechambered to .30-.338 or .308 Norma Magnum (virtually the same cartridge), which will give you .300 H&H performance without the expense of a Magnum length action. Of course the bolt face will need to be opened up to accept the larger case head. Many a Springfield or Enfield has been converted that way.

.300 Winchester Magnum is another option, but you need to weigh the advantage of easily available factory ammunition against a case which requires to bullet to be seated too deeply in order to function in a standard length magazine. When I say "too deeply", I simply mean that a long bullet protrudes far enough into the powder chamber of the cartridge as to reduce the its case capacity.