Bunch of testing with RL23 and RL26 in 300 win... and my results so far.

[Fenix Mike]

I couldn't find a ton of data on people using these, and since we had a pretty mild winter, its already in the 80s here and having to reduce my RL17 loads, so I decided to try their new powders to see if I could get something more consistent.

Here is the history on my setup:
Accuracy International AXMC in 300 win with a Bartlein 1:8 twist 27 inch barrel, using a Silencerco Harvester big bore can
New Norma 300 win brass
Federal GMM Magnum rifle primers
Hornady ELD Match 225 bullets seated .010 off the lands

With the RL17, I was safely getting 2875 fps, with a max of about 2910 before I backed off, however we dont get clouds in Phoenix and my spot is in the middle of the desert, so even keeping the rounds covered, the direct sunlight got them pretty warm. Long as I did my part, 1/2 MOA or better was consistent, minus the occasional flyer I pulled because im pretty impatient when it comes to bench rest, and really only enjoy long range steel.

For the following testing, I was in direct sunlight, around 75 degrees at 9 am, 4500 ft DA, 1600 foot true altitude. Testing done with a Lab Radar

Baseline 10 shot group was 66.5 grains of RL17 which produced an average of 2887 FPS with an SD of 8.5

Switched to RL23 with hopes of similar performance and less temp issues. I did a ladder without changing any other variables and worked as follows (all groups are 5 shot unless otherwise stated):
71.0 Gr - 2858 FPS / 3.6 SD
71.5 Gr - 2877 FPS / 6.0 SD
71.8 Gr - 2895 FPS / 8.4 SD
72.0 Gr - 2904 FPS and heavy bolt lift, so I only fired one round and stopped

Switched to RL26 to see if I could get some more velocity with the slower burning powder
73.0 Gr - 2845 FPS / 11.7 SD
73.5 Gr - 2867 FPS / 2.7 SD
74.0 Gr - 2880 FPS / 7.5 SD
74.5 Gr - 2908 FPS / 6.9 SD

That was as high as I loaded that day and saw zero pressure signs, so I loaded up more and went back the following day in the afternoon to see how the RL26 did in warm weather. The best accuracy came from the 74.5 load.

RL26 testing at 11:00 am - 80 degrees outside and went until about 1 pm - direct sunlight overhead, no cloud cover. Rounds were cold to the touch when I first pulled them out of my bag and stored under my shooting mat until ready to use.
All groups are 5 shot unless otherwise specified - starting load was the same as the finishing load from the day before.
74.5 Gr - 2933 FPS / 3.8 SD (close second best group)
74.8 Gr - 2937 FPS / 7.7 SD
75.0 Gr - 2935 FPS / 1.7 SD
75.2 Gr - 2943 FPS / 10.2 SD
75.4 Gr - 2963 FPS / 7.6 SD (The highest was 2971)
75.6 Gr - 2963 FPS / 11.9 SD (the highest was 2977)

I didnt load any higher than this. The most accurate seemed to be 74.5 and 75.4 from today. I was really excited about the results from the RL26 until I saw the pressure difference from yesterday to today, and its still Feb here. My goal was a consistent 2950 FPS with these, or possibly the new 230 gr Match kings, but I may just settle for 2900 as a "max" and try to find something that doesnt spike so hard with warm weather.

 

[black5.3]

I never had great luck with temp sensitivity and the rl powders...... but every rifle reacts different to powder selection. Im hoping the pound of rl16 i have on the shelf will work out good for my rifles and be consistent.. MV looks promising for both powders. Have you tried the charges that gave the best groups at longer distance and checked for verticle?

 

[Fenix Mike]

I never had great luck with temp sensitivity and the rl powders...... but every rifle reacts different to powder selection. Im hoping the pound of rl16 i have on the shelf will work out good for my rifles and be consistent.. MV looks promising for both powders. Have you tried the charges that gave the best groups at longer distance and checked for verticle?

I only shot 10 rounds to 800 and 1000m real quick after the load testing because thats all I had loaded extra, and it was the 74.5 gr of RL26 load. At those two distances, ballistics were spot on (the 2930 FPS, not the day before's 2900) and had first round hits on both targets (less than 5 mph wind and ive been shooting at this spot for 7 years). Im going to try the bullet at .020 off the lands instead of .010, and I need to measure the case volume of the ABM Norma brass vs the actual Norma brand Norma brass and makes sure they are identical as im about to switch. Should have some more results next week and hopefully push out to a mile.
Edit - just did a "measurement" using Tac powder (smallest ball powder I had) to see capacity differences. The Norma/ABM holds 95.2 grains of TAC, the Factory Norma holds 98.7 grains. Explains the velocity gain, and I will prob have 199 pieces of once fired Norma up for sale shortly

I will say, I ran RL17 in my Remington for a year and about 600 rounds, it was the easiest powder to load, with only once in a great while getting a bit of heavy bolt lift (which I blame on the once fired brass from another rifle and belt bulge more than the load), but the AI is a bit finicky with the ultra tight chamber in the Bartlein barrel. I would love to keep using the RL17 because its cheap, uses 10+ grains less than other powders, always available, and gets fantastic velocity, but this rifle just doesnt like it and seems to really like the slower RL23 and RL26.

 

[black5.3]

Yeah i would agree that you should be in the rl23 or rl26 range with a 300wm.. sounds like it is working out good though. If they group great at 100 and at distance then i would run several strings of +/- .2gr and watch your es/sd and mv to make sure your loading in the middle of your node.

 

[Fenix Mike]

Did some more work today with the powders using the smaller ABM cases (still all new). I was able to get better velocity before getting pressure signs and less powder with the RL26, the RL23 was about the same with anything over 2880 FPS showing pressure. The highest I was able to get today with the RL26 was as follows:

ABM new brass with FGMM Magnum primer
.020 off the lands with 225gr ELD Match bullets

74.5 grains - 2944 fps 6.0 SD
74.8 grains - 2955 fps 6.0 SD
75 grains hit 2970 fps and I stopped at the first round.

These were all done between 1 and 3 pm in 85 degree weather today - direct sunlight and no cloud cover. Pretty sure I found my powder! Pending I get time tomorrow or Saturday, im going to go out early and see how it does with the 50 degree weather and how the velocity changes, if any.

 

[black5.3]

Sounds like a plan. See how it reacts with thb older temps and let us know. Remeber to let the actual temp of the ammo get to the outdoor temp.