So, after reading so many good reports about RL17 I figured I'd get a pound and give it try in a couple of my rifles. I never expected the results I got.
The two rifles I took out were my Browning A-bolt Stainless Stalker in 300 WSM and the other was a Browning A-bolt 270 Win.
To introduce the 300 WSM, it's a solid shooter and a good combination of H4350 and a quality 180 grain bullet would usually get me to 2980 fps with a tight group around a half inch or so, I could push it more, but the groups opened a bit and truthfully I was pleased with 2980.
To start the day I shot a couple groups with my standby load of H4350 with a 180 gr Nosler E-tip. Everything went as expected. Good group that averaged 2982 fps. After the barrel cooled I shot an equivalent load of 65.5 gr of RL17 and the velocity instantly jumped to 3060. The group was below average for this gun at about an inch.
The next set I bumped the charge to 66 gr of RL17 with the same E-tips. Velocity jumped again to 3085, but this time the group shrunk to 1 single tattered 3 shot hole. I wasn't seeing any pressure signs and things were just getting better as I went, so I bumped the charge up again.
Not knowing what to expect I fired 4 shots loaded with 66.5 gr of RL17 again with the 180 E-tip. Velocity came out at 3108, with 3 of the 4 shots duplicating on velocity, and the accuracy was spectacular. Again no pressure signs. I ran out of time to bump up any more, but I doubt I'll push it any further. ES was 3 fps. When you run into a load this cherry you tend to stick with it. I attached a photo of this group for you all to see.
The 270 was close to the the same story. I shot a group with the standby H4350 load and a 140gr Accubond. Everything was as expected. I took the same approach with this rifle as the 300WSM. Start with the H4350 data and work up. I ended up safely pushing the 140 Accubond with 55gr of RL17 to an average velocity of 3140 with a decent 3/4" group.
My 300 WSM components are:
180 Grain Nosler E-tip .523 BC