Originally Posted by
257weatherby
In defence of the Quaterbore.
Worth pointing out that there is a misconception among non quarterbore shooters, that somehow .257 is "little - consider that the .260 that most of you consider as this great deep penetrating aerodynamic cartridge/round, is in fact only .03" larger in diameter than .257, a difference so close that you could shoot cast lead .260 projectiles in a .257 bore.
Comperable bullet weights used for the purpose of a little re education.
A 7mm Rem Mag 120gn Pro Hunter delivered at 3400fps is still doing 2409fps at 400yds and strikes with 1545 foot pounds energy and has an SD of .213.
A .257Wby 120gn Sierra Pro Hunter delivered at 3400fps is still doing 2450fps at 400yds and strikes with 1600 foot pound energy and has an SD of .260.
A .284 7mm08 120gn Sierra Pro Hunter delivered at 3100 is still doing 2160fps at 400yds and strikes with 1250 foot pounds energy and has an SD of .213.
A .260 Rem 120gn Sierra Pro Hunter delivered at 2950 is still doing 2100fps at 400yds and stikes with 1250 foot pounds energy and has an SD of .247
A .257 2506 Rem 117 Sierra Pro Hunter delivered at 3100 is still doing 2210 at 400yds and strikes with 1268 foot pounds energy and has an SD of .260.
So, at 400yds a 2506 Rem has more velocity, more striking energy, and better SD than either the 7mmO8 or the .260 Rem, and these are only standard book max, the 2506 easily loads to much faster, it is normal to get handloads doing 3200fps without pressure. I have the 110gn Accubond doing 3300fps and the 100gn TTSX doing an easy 3400fps, that puppy kills heavy bodied red stags like they got hit by lightning.
So, at 400 yds the .257 Weatherby shades the "mighty" 7mmMag in speed, energy and SD, and SD tranlates directly into penetrative ability- depending on bullet construction, in this case the Sierra Pro Hunter, which lasks BC compared with it's counterpart the Sierra Game King, but is a much tougher bullet and out penetrates it every time (untill out past 400yds or so).The Wby and 7mm Mag will both load faster, but the Wby incrementally pulls away if you go down that route.
I have cleanly shot and killed with one round, heavy bodied adult Tahr out to 400yds many times, with the 117 Pro Hunter out of a 2506, it simply never fails . To imply a comparason with .223 is simply disingenious, and misinforms those without knowledge. The only advantages offered by the .260 and .284 are the heavier weight bullet options. I have a 2506, .270,.308,.257Wby, .270Wsm, 7mmMag, have shot and killed a number of animals with all of them and have first hand direct comparative experience. I would use a .223 for bunnies, hares, wallabies and magpies.
A previous poster refered to the FMJ rounds being used, tumbling because of projectile shape causing instability< spire point and boat tail- the tumble was due to the twist rates causing instability.
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