You really should take a serious look at Sarco! One thing I can suggest is instead of .35 Whelen, look at 9.3x62. It buries the Whelen in every catagory, and a Mauser, large ring is the perfect doner rifle. I shoot a 9.3x57 in a small ring Mauser. It comes really close to .35 Whelen ballistics and can shoot heavier bullets. There would be less work on the rifle to change from 8x57 to 9.3x62. It seems stupid, But 1mm in case length requires mag well work. OAL in the cartridges are as follows, .35 Whelen: 3.34", 9.3x62: 3.29"
FYI, The 9.3x62 is a very popular dangerous game cartridge in Africa. The .35 is not allowed for this purpose. I can tell you, That .366" 286gr bullet from a 9.3x57 packs a big wallop.
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