I suppose you could carefully add powder and see what the chronograph says.,watching for pressure signs as you go.
The barrel may take heavier charges of RL19 than the manuals indicate. That is not unusual.
2720 from a 140 in the 280 is not a lot of velocity ; based on what I've seen from the cartridge, 3000-3080 from a 22" barrel is easily achievable. That includes a custom 280, a M70 Classic and a Ruger M77,all years ago and with Rl22.
If Rl19 does not work I'd look at RL22 next,or maybe the newer R23 which I have not tried yet.
Last edited by BobinNH; 08/30/16.
