I just got back from the range after trying RL-17 in four different calibers. I wanted to see if it lived up to the claim of offering greater velocity. I first worked up loads for my 260 Rem with a Hart barrel. I worked up to the max listed 44.0 grains, under a 120 grain bullet. At the max this load showed good promise with 2943 ft/sec velocity which is above this published velocity of 2912 for a 120 grain bullet. It shot a 3/4 inch 4 shot group. I was using 120 Nosler Bt's.
My Ruger 77 with a E.R. Shaw barrel did not do well with RL-17. At the max listed load I got 2965 instead of the published 3136 so that did not work well and the accuracy was not anything to write home about. So I will forget RL-17 in this gun.
Next I loaded my stock Remington CDL in 280 Remington with 139 grain Hornady BTSP bullets and RL-17. This did a little better than my 270. I was able to get 2924 ft/sec out of this bullet with 54.0 grains of RL-17. No load data for this bullet so I worked up to one grain above the listed load for a 145 grain bullet and did not get the velocity of the 145 bullet. Accuracy was ok. About 3/4 inch 3 shot group.
This powder is suppost to be great in the short mags.. so I tried it in my Winchester model 70 Coyote in 300 WSM. I expected very high velcoities since the data shows 3217 ft/sec with a 165 grain bullet and 68 grains of RL-17. I wanted to see what it would do with a 168 grains Berger VLD, so I started at 64 grains and worked up to 67 thinking this would be all the velocity that I needed. It did not work that way. The 64 grains produced 2981 ft/sec and and one inch group, the 65 grain load produced 3004 ft/sec and a 3/4 three shot group and the 66 grain load produced 3036 and another one inch group. So by the time I got to my max of 67 grains I was still short of 3100 ft/sec and I was not getting great accuracy either.
So what do I think of RL-17 at this point? To say the least I am not very impressed. I know that this was just one try and I have not played with different seating depths and other things, but the powder did not offer what I thought it claimed to offer--greater velocity in these different calibers.
I will do some more loads for my 260 Rem. . I would like to try some 130 grain Accubonds and RL-17 but there is no load data for than bullet at this time.