brybenn - really should slug that bore to find what bullets to buy. CGN'r WhyNot and I have both slugged a "weird to us" BSA barrel marked as 270 Win. It is .270" from face of land to face of land (the "bore"). Is a proper 270 Win chamber. But is .282" groove diameter - a "correct" 270 Win barrel should be .277" or so for groove diameter. It shoots roughly 4 inch "groups" at 25 yards. Perhaps coincidence, but apparently BSA might have been one of the makers of the much earlier P13 in "276 Enfield" - the P13 has the same barrel tenon thread as this converted M1917 by BSA. 276 Enfield, I have been led to believe, happened to have a .270" bore and .282" grooves. So can not really rely on what it "should be" - likely want to slug that barrel and know what it "is".