Just for grins, I went to QuickLoad to compare and contrast:
Chose ...
50gr Sierra MatchKing
26" barrel
Ran the numbers for an isopressure of 60,000psi
Sorted on Velocity for 1st practical powder volume in both cartridges:
Code:
[U]Cartridge[/U] [U]Powder[/U] [U]%Fill [/U] [U]Wt(gr)[/U] [U]V(fps)[/U]
22-250 RL-17 100.0 39.6 3,890
220 Swift RL-17 98.6 42.6 4,043
OK.... a delta of 153fps for same pressure
Now to compare the Swift figures to meet the 3,890 velocity of the 22-250:
Code:
22-250 RL-17 100.0 39.6 3,890 60,000psi (barrel burner)
220 Swift RL-17 94.7 41.0 3,889 52,723psi (barrel saver)
Now for what it's worth, I happned to have RL-15 open about four years ago and my Model 70/Swift (the one I grew up on in the early-mid 50's) now has a tight Krieger barrel and Norma a thicker case so I get slightly higher velocities than I would otherwise expect -- hence the use of a chronograph (Oehler 35):
11/27/07 Overcast/55degr
53grSMK/RL-15/38.0 - 40.0gr/NormaCase/BR2/0.008" OFF lands
At 40.0gr/RL-15
1. 4,028 Press signs normal
2. 4,020 (ditto)
3. 4,026 (ditto)
4. 4,022 (mega dittos)
That's close enough to a 55gr bullet for me, and way more velocity than I need.
So I'm running RL-15/38gr and am very happy to save my barrel at 3,800 and 51,000psi.
The Swift, with 8% more case capacity, lets me do that.
(the extra powder's cheap all thing's considered)