My brother asked me if I could load him some 348's. He has 348 win Jamison brass and 250 gr Barnes original flat points. The rifle in question is M71 24" rifle in nice condition will the load you used in the big book of gun gack for the Browning m71 be okay or does a guy need to back off a bit for an original? I have H4350...mb

Should work just fine, as .348 pressures are relatively low. Might have to adjust it a little for the best accuracy, as .348s (like a lot of lever rifles) can be a little touchy about the exact powder charge.