Home Forums Reloading Big Game Rifles anyone notice Reloader 15.5

I am back from the range with stuff to report on RL-15.5 in the 338-06 and the 9.3x62.
About the rifles - both are JES rebored 1903 Springfields. The 9.3 has about a 23.5" barrel and the 338 is 19" long. With previous loads, the 9.3 has been extremely accurate but the .338 has not yet shot well for me. Both rifles have Leupold M8 fixed 4X scopes, a tiny compact on the 9.3, and a full sized on the .338. Both rifles have long throats and the bullets are loaded to 3.375" for magazine length. Lapua brass for the 9.3, necked up FC 30-06 for the .338. All primers are CCI 200.
My velocity goals for the 9.3 match the good data Mule Deer has published for 60K PSI-ish pressures, and for the 338-06, I am looking for about 100 FPS less than the Hornady max data show due to the 4.5" shorter barrel.
That means ~2650 FPS for the 250AB and just under 2500 for the 286 PT (today I used the 250AB and a no-name 285RN for testing. I bought a few big bags from some guy that got them from an estate. They look just like PPU 285 or Lapua Mega 285).
For the 338-06 I'm looking for 2400' for the Hornady 250RN and 2600 for the 225 SP. I shot both those bullets today.
I loaded two rounds each for three charges each to get in the ballpark. Below I will try to summarize the results but the formatting might get goofy when I post it. I list the two speeds and the center-to-center distance between the two rounds.

9.3x62, 250 NAB (goal = 2650')
60 grains - 2421, 2454, 0.27"
61 grains - 2511, 2494, 0.45"
62 grains - 2542, 2547, 0.20"
Summary - looks like outstanding accuracy potential, and room for 1.5 to 2.0 grains more powder to reach the goal.

9.3x62, No-Name 285RN (goal = 2500')
58 grains - 2290, 2266, 0.46"
59 grains - 2312, 2314, N/A, the first round hit just off my paper - it was just about 2"
60 grains - 2368, 2358, 0.95"
Summary - looks like at least 2 more grains needed to reach the speed goal.

338-06, 250 Hor RN (goal = 2400')
50 grains - 2233, 2230, 1.00"
51 grains - 2292, 2266, 2.23"
52 grains - 2330, 2322, 1.70"
Summary - maybe another 1.5 grains to reach 2400', accuracy potential not exciting (but it is certainly minute-of-moose, and about as good as this rifle has ever shot before)

338-06, 225 Hor SP Interlock (goal = 2600')
54 grains - 2504, 2489, 0.47"
55 grains - 2549, 2530, 1.06"
56 grains - 2594, 2589, No kidding one hole. Barely perceptible elongation - can't measure it.
Summary - Excellent! I hit my speed goal of ~2600' and the accuracy potential looks good. Very excited to repeat the 56 grain charge with more rounds. These 6 rounds formed a cluster much smaller than the average 3-shot group this rifle has delivered with previous loads.

I hope these results will help others develop their own loads with RL-15.5. Please post your results. Don't forget my rifles have long throats and are loaded to magazine length. I will sneak up closer to the velocity goals next Wednesday and report back. Will also try the 210 NPT in the 338-06 and see if it plays well with RL15.5. I really hope so but can be happy forever with the 225 Hor SP if it keeps up what it did today.

Cheers,
Rex

Is the bulkiness of the powder giving any problems in either case? I can get exactly 59 grains (settled) into a fired Nosler/norma 35 Whelen case with 250 partitions at 3.33 COAL. 59.5gr needs a deeper setting on the seating die to get the same COAL.

Should get chrono data tomorrow. 58gr of this stuff under a 250 Speer is a very mild feeling load... gives 2450 fps from a 20" Whelen with a very short throat, primers completely round. Hoping to break 2500 but not sure the powder will fit. Obviously 2450 is fine. I think I'd be at 2400 fps in a SAAMI chamber but I'll test that tomorrow, too.

In the 9.3x62 in once fired Lapua cases, I loaded up to 62 grains RL-15.5 under the Lapua 285gr Mega, and 64 grains under the Nosler 250 AB, both bullets at 3.375" COAL. Here is what the case fill looked like with my little 4" RCBS drop tube.


The 285 Mega seated perfectly, since it's a short bullet, and the base just snugged right up to the 62 grain charge

The 250 AB required some decent compression but seated fine. Both it and the 286 PT extend below the case shoulder at 3.375"

I cobbled up an 18" aluminum drop tube and dropped the same 64 grain charge as pictured above with the 250 AB, and it definitely helped. It makes the 64 grain charge look closer to the original 62 grain charge pictured above with the 285 Mega.

So bulk is an issue, but I think I'm going to be fine in my rifle, with the 3.4" magazine and long throat. That long throat is standard for most all 9.3x62s so RL-15.5 may be a player for this cartridge.
I will follow up with the loading bulk for the .338-06.
From prior testing, I know that my 35 Whelen AI cases have about 0.3 grains of water more capacity than my 9.3x62, when both are filled to the base of a 250 grain bullet seated 3.375", so I am hopeful for that chambering as well.

Cheers,
Rex