I finished a work-up with RL-23 in my .260 AI recently and thought some might find the results interesting. In short, I found this powder long on velocity and capable of producing excellent accuracy. Data follows:
Rifle -
Savage PTA, .260 AI, Criterion large shank bull profile, .160 freebore, 28", 1:8" twist
Sightron SIII 8-32x56
Load -
Lapua .260 brass, fire formed and 2x fired, annealed
Sellier & Bellot LRM primer
RL-23, 46.1 grains - 47.6 grains in .3 increments
Berger 140 gr. Hybrid seated to 2.180" CBTO
Conditions
44* F, mostly sunny, light and variable winds 7 - 8 o'clock
The OCW work up was done without the MagnetoSpeed attached and I used a seating depth that has worked well for this specific bullet and several others as a test value.
Five shot groups were fired for each charge weight at 100 yards off of a rest. Each charge produced decent accuracy but the groups started to tighten up at 46.7 grains. Approximate group sizes were:
- 46.1 gr., .61"
- 46.4 gr., .77"
- 46.7 gr., .52"
- 47.0 gr., .47"
- 47.3 gr., .30"
- 47.6 gr., .41"
47.6 was probably a bit on the warm side - the brass has some slight ejector marks, although the primers did not look particularly stressed and the bolt lift was fine. Since 47.3 produced a very nice, symmetrical group I loaded up 15 more at this charge weight. Ten were fired with the MagnetoSpeed on the barrel and a five shot group was fired to confirm the accuracy. Chronograph results were:
Series 1 Shots: 10
Min 3,033 Max 3,054
Avg 3,041.40 S-D 6.98
ES 21
Series Shot Speed
1 1 3,036 ft/s
1 2 3,037 ft/s
1 3 3,054 ft/s
1 4 3,041 ft/s
1 5 3,051 ft/s
1 6 3,046 ft/s
1 7 3,033 ft/s
1 8 3,035 ft/s
1 9 3,039 ft/s
1 10 3,042 ft/s
My thoughts - Holy crap! That's pretty fast! The string statistics were solid as well. I was hoping the accuracy validation would hold up.
Here's how that turned out:
The one out to the left was called - knew it as soon as the shot broke. Oddly, it was not the typical fifth shot spoiler, rather it was the second shot in the string. The other four are in the low twos - high teens. That's plenty good enough for my purposes.
I'm pleased with RL-23's performance. The 47.3 gr. charge showed no signs of pressure - not a hint of an ejector mark and case head measurement of the fired brass was no different than a sized case and the primer pockets seemed unaffected. Given the velocities, I measured each case head very carefully and paid close attention to the primer pockets and I'm comfortable with this load in my rifle. I may fiddle around with seating depth just a touch but it's one of those happy situations that if I never get around to it, no big deal. Getting 6.5-.284 speed out of the .260 AI case with excellent accuracy and not trashing the brass is a great outcome, IMO. The powder's temperature stability is a nice bonus, too.
I'll be giving it the pasture test one of these days (we have 600 yards marked off in one of my neighbor's pastures) and see how the load holds up at long range.
Lastly, thanks to @ShootDots for the guidance. A couple of his posts substantially narrowed the possibilities for me.
Rifle -
Savage PTA, .260 AI, Criterion large shank bull profile, .160 freebore, 28", 1:8" twist
Sightron SIII 8-32x56
Load -
Lapua .260 brass, fire formed and 2x fired, annealed
Sellier & Bellot LRM primer
RL-23, 46.1 grains - 47.6 grains in .3 increments
Berger 140 gr. Hybrid seated to 2.180" CBTO
Conditions
44* F, mostly sunny, light and variable winds 7 - 8 o'clock
The OCW work up was done without the MagnetoSpeed attached and I used a seating depth that has worked well for this specific bullet and several others as a test value.
Five shot groups were fired for each charge weight at 100 yards off of a rest. Each charge produced decent accuracy but the groups started to tighten up at 46.7 grains. Approximate group sizes were:
- 46.1 gr., .61"
- 46.4 gr., .77"
- 46.7 gr., .52"
- 47.0 gr., .47"
- 47.3 gr., .30"
- 47.6 gr., .41"
47.6 was probably a bit on the warm side - the brass has some slight ejector marks, although the primers did not look particularly stressed and the bolt lift was fine. Since 47.3 produced a very nice, symmetrical group I loaded up 15 more at this charge weight. Ten were fired with the MagnetoSpeed on the barrel and a five shot group was fired to confirm the accuracy. Chronograph results were:
Series 1 Shots: 10
Min 3,033 Max 3,054
Avg 3,041.40 S-D 6.98
ES 21
Series Shot Speed
1 1 3,036 ft/s
1 2 3,037 ft/s
1 3 3,054 ft/s
1 4 3,041 ft/s
1 5 3,051 ft/s
1 6 3,046 ft/s
1 7 3,033 ft/s
1 8 3,035 ft/s
1 9 3,039 ft/s
1 10 3,042 ft/s
My thoughts - Holy crap! That's pretty fast! The string statistics were solid as well. I was hoping the accuracy validation would hold up.
Here's how that turned out:
The one out to the left was called - knew it as soon as the shot broke. Oddly, it was not the typical fifth shot spoiler, rather it was the second shot in the string. The other four are in the low twos - high teens. That's plenty good enough for my purposes.
I'm pleased with RL-23's performance. The 47.3 gr. charge showed no signs of pressure - not a hint of an ejector mark and case head measurement of the fired brass was no different than a sized case and the primer pockets seemed unaffected. Given the velocities, I measured each case head very carefully and paid close attention to the primer pockets and I'm comfortable with this load in my rifle. I may fiddle around with seating depth just a touch but it's one of those happy situations that if I never get around to it, no big deal. Getting 6.5-.284 speed out of the .260 AI case with excellent accuracy and not trashing the brass is a great outcome, IMO. The powder's temperature stability is a nice bonus, too.
I'll be giving it the pasture test one of these days (we have 600 yards marked off in one of my neighbor's pastures) and see how the load holds up at long range.
Lastly, thanks to @ShootDots for the guidance. A couple of his posts substantially narrowed the possibilities for me.
