H (Hervey, not Hurvey) Lovell was a "do it all" guy. He did stocks as well as metal work. I wouldn't be surprised if it does turn out to be chambered/bored for Savage .22 HiPower. The cartridge retained a lot of popularity in the era when this fine gun was made. (Heavy/long bullets have always been recognized as advantageous for long(er) range work and the .22HP with its 70gr. loads delivered them in an era when .224 bullets rarely were obtainable in heavier than 55gr. weights. Let's hope that if this rifle does indeed have a .227/.228" bore and chambered for .22HP that it also has a faster twist than what Savage provided in the M1899 barrels, 1-12".) If Lovell did the work on this gun I bet it'll be first rate.
If such is the case, .228" bullets can be found with a little diligence, and brass can easily be made from .30-30 and .25-35 brass.
I just found and bought an original Ideal .228151 mold to use with my Pope-Ballard in .22WCF. It should be around 50 grain bullet, but wont know until I cast some bullets. This is the final mold I needed for the Ballard's 3 barrel Pope takedown set. I found a .28 Pope and .32 Pope molds for the set for the other barrels in .32-40 and .28 pope Special. Figured I'll never find a .22 Pope mold for the WCF barrel, so the Ideal will be close enough.