I have acquired one of these, and have read the SHIKARI models were built in both 44 mag and 45-70. I think that means the receiver is SB2. According to an old H&R post was built in 1974 as per the serial number, and if the pressures of the 44 mag being what they are would mean the 45-70, could handle pressures higher than the old trap doors.
I want to lengthen the chamber, and fire both long bullets (up to 500 grain) and paper patched bullets. Any one have any thoughts?