I can understand the "desire" to aquire a .257AI.
Probably the best match of case capacity to bore diameter. Should be a bit more efficient. Should do essentially what the .300WSM does compared to the .300WinMag.
I DON'T LIKE THE 115gr Nosler Ballistic Tip.
From my "Bob", it's "ok" on smaller deer at a distance (over 200yds). It's proven to be far to "frangible" for the .257WbyMag.
I'm curious about the load above mentioned of 42.3gr IMR4350 in the AI. I use 43.0gr with a 115-117gr in my 'regular' "Bob".... But then again, it's a 3" Bob chamber in an E.R.Shaw 22" bbl on an M98 custom.... Apples to Oranges ?
My circa 1980's Sierra manual for the .257AI shows a max load of 46gr for 2,900fps and the companion Hornady manual with the .257RCBS (28deg shoulder) shows 44.5 also for 2,900fps.
fwiw; my "Bob" gives 2,900fps with H4831 and 117gr Hornady or Sierra, but then again, it's a 3" Bob with a generous throat in a long action. It more closely follows the .257RCBS data than it does the various +P listings in the more recent Speer and Lyman manuals.... Especially with the slower burning powders (4350's and 4831's to include RL22).
However, the Hodgdon's listed max "non- +P" loads have always been "accuracy" loads in my rifle. Even 30yrs old this year (built in 1983), and with some mid-barrel pitting, with 44.0gr of H380 and a Sierra 100gr (Prohunter or GameKing) it gets 3,100fps and near 1/2moa... Ditto 45.0gr of H414, IMR4350, or 48.5gr of H4831...
The .257AI with a 21" bbl should be very, very close to a 22" .25/06 with ~5-10% less powder; IMO... Of course a 22" bbl .25/06 is a hobbled throughbred race-horse...Really needs a 26-27"bbl. The .257wby likewise with a 24"bbl (like my Wby Vanguard) needs a 27-28"bbl to really deliver its "goods"...
