By the way, has anyone mentioned the 125 grain Sierra FNHP? You can load that sucker up to almost 2600 fps in the standard 20 inch carbine. It hits like a hammer and shoots about as flat as anything else out to 300.
Those are ballistics not too dissimilar to a 257 Roberts.
Not really. Not even close to what a Roberts can do.
Using the .30-30 load referenced and .257 Roberts +P velocities as chrono’d from my rifle, a comparison tells a very different story.
.30-30 = Sierra 125g FN/HP, BC .119 @ 2600fps, 20” carbine
.257 Bob = Swift 120g A-frame, BC .382 @ 2947fps, 22” barrel Ruger M77
.257 Bob = Nosler 110g AccuBond. BC .418 @ 2163fps, 22” barrel Ruger M77
Given 100 yard zeros and a 300 yard target:
Sierra 125g FN/HP = -33.5”, 1088fps, 329fpe
Swift 120g A-Frame = -12.0”, 2298fpe, 1534fpe
Nosler 110g AccuBond = -9.7”, 2538fps, 1573fpe
Love my .30-30 but for longer reach my Roberts wins every time. By a mile.
Not really. Not even close to a mile... 21.5" to 23.8".
\
To get drops like that (21.5" to 23.8") with the Sierra 125g bullet and a MV of 3600fps you have to have a 200 yard zero. My calculations were for 100 yard zeros. By the way, in checking my previous calculations it appears I made some minor errors. Corrected data with 100 yard zeros is shown below. Not a lot of difference but I thought it worth acknowledging my original error.
Again, using these loads:
.30-30 = Sierra 125g FN/HP, BC .119 @ 2600fps, 20” carbine
.257 Bob = Swift 120g A-frame, BC .382 @ 2947fps, 22” barrel Ruger M77
.257 Bob = Nosler 110g AccuBond. BC .418 @ 3163fps, 22” barrel Ruger M77
Corrected data for 300 yards with 100 yard zeros:
Sierra 125g FN/HP = -34.9”, 1065fps, 315fpe
Swift 120g A-Frame = -12.0”, 2298fpe, 1534fpe
Nosler 110g AccuBond = -9.8”, 2516fps, 1546fpe
Now let's compare the two cartridges using a 200 yard zero since that appears to be your preference:
Sierra 125g FN/HP = -22.6”, 1065fpsfps, 315fpe
Swift 120g A-Frame = -7.2"”, 2275fps, 1379fpe
Nosler 110g AccuBond = -5.96”, 2516fps, 1546fpe
And for fun, let's compare both with MPBR (Maximum Point Blank Range) zeros for a target 6" in diameter. This will give a maximum deviation from line of sight of +/- 3" and is how I zero all my rifles:
Sierra 125g FN/HP = zero
180 yards, MPBR
207 yards, -3", 1378fps, 527fpe
Swift 120g A-Frame = zero
246 yards, MPBR
288 yards, -3", 2200fps, 1410fpe
Nosler 110g AccuBond = zero
264 yards, MPBR
310 yards, -3", 2496fps, 1522fpe
Much as I love my .30-30, the facts are it doesn't compare well against the capabilities of my .257 Roberts, especially as the target ranges get longer.
