RL23 and 260AI

[Fast14riot]

Following a post @JLT made a while back experimenting with RL23 in his 260AI I decided it would be a good powder for me to try. I picked up a keg and initially did not have good luck with it using Lapua brass and 140RDF. H4831 shot much better for me. Well, after losing primer pockets in the Lapua brass after 5-6 firings and running a compressed load with the 140RDF, I was almost out of H4831 and the 140RDF. So, I bought some Peterson SRP brass. Ran my current load through it for fire forming and a couple of matches, now to test the RL23 again. I was also switching from the RDF to the Berger 140VLD Target. Here are my results from today...

Berger 140VLD Target and RL23 load testing.

Atmospherics: Linden Range, Linden, CA
ASL ~100' 73°F, 29.9in/Hg
Wind 0-3, swirling

Rifle:
Rem700SA
CBI Remage, 260AI Match chamber
Jewell trigger
Sightron SIII 8-32x56
Rem 40xb stock (no pillars or bedding)
Cowan front rest, Protektor rear bag
Shot from bench, 200 yards.
Velocities collected by MagnetoSpeed Sporter

Load:
Peterson SRP 260 brass. Fired 2x, not annealed Shoulder bump 0.002"
RL23
Berger 140VLD Target, not sorted
Federal 205M
2.325" BTO (-0.010")

Test procedure:
3 strings from 46.5gr through 48.3gr in 0.3gr steps. Groups fired round robin, i.e. string 1, charges 1-7, string 2, charges 1-7, string 3, charges 1-7. This eliminates firing that tiny group in a favorable condition but may not actually be a good node.

Looking at the entire target, it is clear to me that this powder likes to live in the upper half of acceptable pressure levels before velocities stabilized. I had already determined this bullet likes a jump of 0.010" with a previous load using H4831, so all rounds were loaded to current throat dimension.

Based on these results I will load charges between #5 and #6, as there is only an 11fps difference between them and vertical dispersion of each group as a whole was minimal. I do not calculate SD for 3 round groups as it is statistically insignificant, so averages are best for small sample sizes, but I do take into account ES.

If you cannot see the pictures with the velocities, let me know and I will type them out as well.

 

[BAT man]

I ran my .260 AI at 2970 with 47 g of RE23 and a 142 smk at the nightforce ELR in Wyoming, last june. Load worked extremely well. The Ace barrel I had put in only had 60 rounds through it when I shot that match. The barrel set at the end of the first day, and I had to adjust the kestrel 30fps faster to adjust for the velocity change. I did drop the charge to 46.2 to keep it at the 2970 velocity.

 

[Fast14riot]

For those interested in comparing, here is the original thread published by JLT.

http://forum.accurateshooter.com/threads/260-ai-and-rl-23-results.3939877/

 

[JLT]

47.7 and 48.0 look pretty good in your barrel! 48.0 looks like the POI bottom and the vertical looks great for both.

What's your barrel length? I got a bit more speed with equivalent charges and I was running a 28". I just rebarreled (28" again) a couple of weeks ago and the last trip to the range settled the barrel - I'm going to have to re-tune a bit as this barrel is a bit faster than the last.

I agree with you - this powder runs best at the upper end of pressure.

 

[Fast14riot]

This barrel is 26", my next will be either 28 or 30. Otherwise the speeds seem pretty equivalent between your barrel and mine

 

[Fast14riot]

So due to life and the missus changing jobs, I didn't get a chance to stretch this load out until yesterday at a bi-annual fun match called the "No Bull" match. It's shot on a silhouette range, so distances are 200, 300, 385, 500 meters.

I took my tested loads and decided to load 47.8gr of RL23, keeping it on the low end of the node and allowing for it to heat up a bit.

This match format is prone from a Harris bipod and rear bag, using small steel and other targets and each string will jump back and forth between distances. I.e. shot 1 300m small bore size pig silhouette, shot 2 500m 4" square. Shot 3 500m golf ball, shot 4 300m 2"x3" vertical steel, shot 5 500m 2"x9" horizontal steel, etc...

The toughest targets were the golf balls (47mm/1.68" diameter) on a nail at 500m! I managed to hit the nail twice at 500m (does not count), but did manage to get golf balls at 200, 385m and a ping pong ball (40mm/1.4ish" diameter) at 200m. Wind was 0-5 knots all day, fish tailing from 12 o'clock.

This load shot incredibly consistent across all distances with very little vertical dispersion that can be attributed to the load. I had my bipod come loose on stage 3, and I missed some pretty big targets, like a 7" round and a life sized standing squirrel.

Heres some pics for you! To say I'm happy with this load is a bit of an understatement. This match is a team match, my shooting partner had some troubles with his fundamentals, but we still managed to post a respectable team score that should be good for 4th or 5th. My individual score was 2nd highest of the day at 25/40!