I'll be adding to this but in case people wanted to buy some to check it out on their own here's what I got so far.

Note that this was all done in a 20" Whelen with a short throat; about half the normal freebore and a slightly tighter throat dia than SAAMI.

As everyone has been saying this powder is definitely slower and it's definitely bulkier than RL15. Not positive it's a good fit for 250 bullets but I think it could turn out that way. For 280 A-frames or 310 Woodleighs it might be great.

Based on what I worked up with 310 Woodleighs it developed velocity and pressure about the same as Big Game and MR-2000. It maybe built pressure a tiny bit sooner than Big Game but they were very close.

Back to the 250's:

I used 250 hotcor at 3.35 COAL, in virgin norma/nosler brass (same/same as far as I can tell). I could only get 58 grains without crunching powder. That's after settling the powder with an electric toothbrush. It was way up in the neck.

58 grains of ole RL15 is a pretty warm load under a 250 Speer or Partition for this rifle: it gets a 250 partition motivating around 2540 fps, so I decided not to go any higher on round one for this RL15.5. Turns out I should have gone higher. Unfortunately, more than 58gr of this stuff is only going to fit in fired brass.

Anyway this stuff is accurate, I wasn't shooting for groups but most of the bullets from 55gr up to 58 grains went into basically the same group and it built velocity very linearly.

58 grains of RL15.5 under a 250 Speer hotcor topped out at 2450, about 90-100 fps slower than the same charge of RL-15.

55 grains of the 15.5 got 2335 and then it built pretty predictably up to 58grains at 2450.

60 grains will definitely fit in a fired case (3.35 coal) without compressing too much so that is next. I'm guessing 60 grains should break 2500 fps which for a temp stable powder is not a bad deal. But them cases are full.

It did fairly well with 310 Woodleighs but I'll put that in a separate thread.

Have you played with imr4350 any?

Im running 250's right around 2500 in my 350mag and i didnt have any noticable pressure signs

It sounds like it's worthy of some development of my 9,3X62 loads. I might try it in my 8X57JR loading, too. Thanks for the post.

I was gonna try a 4350 with the 310's. With the 250's I've had such good luck with IMR4895, RL-15, MR-2000...that it's sort of hard to try something else unless it gives me something good like temp stability. Those powders all make around a little under 2550, but they're definitely warm. MR-2000 seems to go the fastest and fit the most in the case.

With the 310 Woodleighs it acts really close to Big Game. I think there was a one grain difference in where they topped out. 57gr of big game was starting to show pressure and 2275 fps, and the same thing happened to RL 15.5 at 56 grains, same velocity, maybe a tiny bit more pressure.

Hope that helps. It is bulky.

TX35W
I run hogdon CFE223 in my Whelen using Speers reloading data. I have a standard Whelen chamber and can load to a coal of 3.4 inches this gives me a chroboed velocity of 2,700fps out of my 25 inch one in 12 barrel.

With the 310s I use an 18 inch drop tube and H4350.
This allows more powder in the case without any compression. My best loads gave 2,455 fps and no pressure signs but recoil was rather stout. I settled on 2,350fps and call that my working load.

With CFE223 275gn Woodleigh PPSP projectiles chronoed a tad under 2,600fps with no pressure signs
Bob

TX35W
I run hogdon CFE223 in my Whelen using Speers reloading data. I have a standard Whelen chamber and can load to a coal of 3.4 inches this gives me a chroboed velocity of 2,700fps out of my 25 inch one in 12 barrel.

With the 310s I use an 18 inch drop tube and H4350.
This allows more powder in the case without any compression. My best loads gave 2,455 fps and no pressure signs but recoil was rather stout. I settled on 2,350fps and call that my working load.

With CFE223 275gn Woodleigh PPSP projectiles chronoed a tad under 2,600fps with no pressure signs
Bob

RL 15.5 seems to work well in the .375 H&H with 270 and 300 grain bullets. I've been using 73 grains of RL 15.5 with a 270 grain TSX for about 2670 fps in a 24 inch barreled CZ 550. I get sub MOA groups in my rifle. However, I don't have any experience with the .35 Whelen.

My experience with RL 15.5 in the .375 H&H and the .338 WM is that charges are very similar to book values for RL 15 except I get a little more velocity.

I run the 250's over MR-2000, IMR 4895, RL15...all are very accurate but just wanted to try this new RL15.5 for temp stability. MR-2000 gives the best velocities from both my 20 and 26" 1:12 but its def a bit temp sensitive.

I will try the H4350 with the 310's. In my 26" Big Game and Mr-2000 both get the 310's to 2400 without any noticeable pressure signs but 2250 seems to be the reliable max in the 20". Maybe the slower powder will help.

TX35W
I have used CFE223 in both my Whelen and the sons 308. I use standard Remington 9 1/2 primers and don't have trouble with temperature sensitivity. I have use it in temps for -5C in our colder areas upto 38 degrees celcieus in Namibia and as high as 40 degrees celcieus in the Australian bush.
I have had no pressure excursions or problems in the hot weather or slow ignition in the cold. Pull trigger, gun goes bang, eject cartridge no problems.
If you go H4350 in the standard Whelen you get 59gn and that is a very compressed load with the 310s.
I use an 18 inch drop tube and can get 63gn of H 4350 in with minimal compression. This load is safe in my rifle only. All other should work up from minimum. That load gives me 2,455 fps chronoed with the 310gn Woodleigh RN. This is a very potent load and recoil is noticeable. Pressure is still mild in my rifle that has a standard Whelen chamber.
Bob

That's what I'm wondering as well. 250 gr. NABs at 2550 fps in the 9.3

I've yet to come across a burn rate chart that lines up RL-15, Varget, RL-15.5, and RL-16

Mark me down as very interested in 9.3x62 results too.
I have the one Nine-Three, a 35 Whelen AI, a couple .308s, and a new 8# jug if RL-15.5
So far have only tried it in the .308 with 168 BT and 155 Scenar. VERY accurate (but not a lot more than Varget) and much slower than Varget so far. RL-15.5 is just so very bulky it's hard so far to get enough in the .308 case.
Was shooting 2000-MR previously in the Whelen with spectacular results but hoping for a more temp-stable load.
in the Nine-Three - very happy with Mule Deer's 60K PSI-ish loads for the 250 AB (Varget) and 286 PT (Big Game) but very willing to try something new. I have plenty of BG and 15.5 but getting critically low on Varget.

Keep those results coming fellas,
Rex

RL15.5 is definitely slower than RL15. In my rifle it's 90-100 fps slower with 250gr bullets at the same charge weight. Your results may vary but I can't get enough RL15.5 in a virgin Whelen case to cause any pressure signs at all with a 250 Speer. Which is not the case with RL15.

If you use RL-15 data you definitely won't hurt anything but it'll definitely be slower.

TX35W
When you stuffed in all the 15.5 it would hold under the 250 Speer, what kind of velocity did you get?
And how many grains did that stuffing end up being? I was going to jump into some work in my Whelen AI and 9.3x62 but will take all the baseline data I can get. Good words about the lack of pressure with a very full case. This is what I have seen so far in the .308 Win with 155 and 165 bullets.
Thanks in advance,
Rex

58 grains fit in the virgin stuff but I think 60 fit in the fired case (haven't gotten around to loading 60gr yet).

Velocities at 58grains were around 2450 in a 20" and 2540 in a 26" but both those guns have pretty short throats so would definitely be slower in a SAAMI throat.

Judging from the velocity progression I saw, I would guesstimate that 60grains of RL15.5 (more or less) would do about what 58gr of RL15 does (more or less) in a standard Whelen case under a 250. But that is just guessing.

Will hopefully get some more data this week.

I won't get to shoot them until Wednesday, but I have a little 9.3x62 velocity ladder (2 rounds per charge) with 60, 61, and 62 grains RL-15.5 with the 250 NAB, and 58, 59, and 60 grains with an unknown 285 grain that appears identical to the Lapua Mega or PPU 285s. I have a ton of the 250 NABs I got for dirt cheap a couple years ago from SPS so I can afford to play with them for basic testing, but I am really short on the 286 Partitions so I plan to learn as much as I can with these cheap 285s before shifting to the $$$ bullets.
The loads above fit pretty well in once-fired Lapua 9.3x62 cases. The 62 gr / 250 NAB was a little compressed, but I can get just a little more under the 285. We will see, and I'll report back after firing.

Cheers,
Rex

Good luck fellas. I’m using PP2000 in my 9.3 with 250 Accubonds and Swifts. Both run around 2750 and I like what they do. Be neat to see what else is in that same space.

Great thread! I’ve got some 280gr A-frames I want to work up a load for as well as the 250gr AF. I have “all” powders so I can go to “THE” powder, whatever it is. CFE?…

TRexF16
If you use a 1 to 2 foot drop tube you will be amazed how much extra powder you can get in.
I use a 2 foot drop tube and can get 63gn of H4350 in my wheken with minimal compression. Without it 59gn of H4350 is very compressed. Might be worth a try if it gives you an extra 4 or 5 grains. A pia yes, worth it definitely.
Bob

Using CFE223 in my 35 Whelen I can safely get a chronographed max of 2,690fps with the 275gn Woodleigh PPSP with out any pressure signs. I backed off a little bit and settled on 2,600fps as my working load. That is in a 25 inch 1 in 12 stainless steel barrel.
With careful loading you should be able to get that or close to it depending on barrel length.
Bob

Kinda depends on how much temp sensitivity you're willing to deal with. I'm leaning toward Big Game or RL15.5 for 310 woodleighs. PP 2000-MR is sick for speed and accuracy for 250's and is basically equivalent to Big Game under 310's (Big Game had less ES).

But for me under 250's if I work up a 2000-MR load in summer here and hunt in winter in a mountain state (100 degree temp swing) MR-2000 changes speed enough to drop out of the node and act funky (and very radically change my POI at 300 yards). It all still went bang, no hangfires etc, no change in recoil, but I'm changing powders. Earlier this week I ran the Labradar on last year's 2000-MR loads...they were 2560 fps last fall (mild temps) and earlier this week (hot temps) they were 2650fps (90 fps increase)

All of which to is to say...I keep collecting data that 2000-MR is very temp sensitive. Plenty of people love it and I did too until the above mentioned issues and it might not be an issue for you in the PNW or anywhere else with moderate temp swings. CFE I have but haven't used...but I have possibly heard that it has the same temp sensitivity as PP 2000-MR.

As far as yer 280 A-frames...I used both Big Game and RL-15.5 (new stuff) under a 310 Woodleigh...

With them 310's, RL-15.5 got to 2240 before it started showing pressure (20" rifle) and Big Game got to 2260 or so (same as 2000-MR). Didn't work up carefully in my 26" Whelen, just fired a few extra rounds, they showed less pressure than in the 20" and were getting 2375 fps with round primers. Again, that's a 26".

310gr at 2375...should be a great load for the 75 lb deer we have here.

Managed to find a load under 250gr bullets that works well. 59.5gr RL 15.5 in once fired Nosler brass, CCI 250 mag primer, 3.34 COAL (3.33 also worked but crunched powder), 250gr partitions.

2500 fps in a 20" barrel (shorter than SAAMI throat) ES of 18. I could not get any better than 3/4 MOA but it always gave nice round groups. I tried swapping in CCI std primers, no change in either velocity or ES or group size. Tried WLRs and the groups got slightly bigger, velocity was basically unchanged.

Worth noting that 59.5grains won't fit in unfired nosler/norma brass: it comes almost to the top of the case. But it will fit in once-fired Nosler/Norma and once you settle it (electric toothbrush) a 250 partition (or Speer) will seat at 3.34-3.335 COAL with no powder crunching (or minimal).

3/4 moa is plenty accurate for what I plan to shoot with a 250gr partition, but it's not a particularly accurate load for this rifle. With either 250 speers or 250 partitions, RL-15 gets 1/4-1/3 moa, so does IMR-4895, and so does PP 2000-MR. The RL-15 and PP 2000-MR groups are also going about 50 fps faster so it's possible there is just a higher accuracy node for this rifle that I can't hit with this powder.

But for the (still unproven) temperature stability, I'll take it.

Is this better than Varget? Probably not, but I've been stingy with my Varget supply as I've got other things I need it for. In some very quick and dirty testing, 57 grains of Varget in this rifle did more or less the same thing.

For what it's worth, here is 63 grains of RL-15.5 in once-fired R-P 35 Whelen (AI) brass, trickled through an 18" drop tube. It is very bulky.

I loaded test charges of 61, 62, and 63 under the 225 NAB at 3.375" for a test this week. Will report after shooting on Wednesday.

Rex

That's about how full my standard necks are if I slow trickle them with 59-59.5 grains. Looking forward to your results. Varget is the powder I use for the 225 NAB...I also seat them at 3.375.

TX35W,
Varget is very accurate in my rifle with the 225 NAB over 60 grains for a little over 2700 FPS. 2000-MR is a good 120 FPS faster and just as accurate but lacks Varget's outstanding temp stability.
I did a pretty extensive comparison of all available data for Varget, and RL-15.5 using the same bullets in the same chamberings, and the max published charges for RL-15.5 are consistently 1-3 grains higher than Varget.
With their respective 225 gr bullets, Nosler lists 60.5/Varget at 2800' as max, and Sierra lists 63.3/Varget for 2750'. So I am very comfortable with 61, 62, 63 as my first three steps on the ladder, will be targeting 2750-2800 FPS and expect I'll need another grain or so to reach that. Which, as we've found, might not fit.

Cheers,
Rex

Verbal portion of the report: It looks exactly as I wrote above. 2750-2800 FPS is going to take a grain or two more than 63 in my 35 WAI, and that probably won't fit. Going to have to take what I can get with 63 or maybe just a few tenths more. Looks like 2725-ish for 63/RL-15.5 at 72-82F ambient during the shooting session. Accuracy potential looks outstanding - for the next trip to the range I will load a few more at 63 and see what kind of a real group I can get. Pressures appeared to be very low. Quite rounded primers (yeah - I know. But I shot nothing but CCI200s today in four different rifles and it is easy to make relative judgements about primer appearance in that case). My assessment so far is that RL-15.5 is not too slow to optimize the 225 grain in the Whelen, just too bulky. But it is very accurate, it appears. More to follow with a better sample.

Pictorial portion of the report: All the measurements and speeds and load data is on this page. [EDIT: I left off the OAL. It's 3.375", which is still far off the lands in my long throated chamber.]


Cheers,
Rex

Great 35 Whelen info fellas. Thank you!

I'm excited to take 9 rounds of the 63/RL-15.5 load to the range on Thursday to do a final sight-in as my backup rifle for my AZ elk hunt at the end of Sep. I'd be happy to make it the primary, but I have already killed two bulls with this Whelen, and it is my "new" 90 year-old 9.3x62's turn.
That rifle will also be fueled with RL-15.5.
I have high hopes for the Whelen on Thursday based on how good the 6-round work-up ladder looked with the 225 AB two posts above. Will report.

Short version is I did not cut the one-hole groups that the initial ladder pictures above indicated I might...
I had some scope adjustments between each group to get to the POI I needed for my hunting sight-in, but those should not have had that great of an impact on my groups.
So I shot three 3-shot groups at 100 yards with the 63/RL-15.5 charge under the 225 AB. 3.38" OAL (still a big jump to the lands) and CCI200. Rifle is a 35 Whelen AI. Temps were 66-79 F.
I missed three chrono readings, so with n=6 the speed was 2716 FPS with an SD of 5.
Groups were 2.11, 1.11, and 2.01"
I may have been shooting a bit poorly, but it didn't really feel that way. I'll take this as the back-up to my 9.3x62 on my upcoming elk hunt.

I'm really looking forward to trying more of the RL-15.5 with the 155 Scenar in the 30-06. That is showing a lot of promise in the one trial I made with it so far.

Cheers,
Rex

Posted to another thread. This powder may be the chidt for lighter bullets in the 30-06.
RL 15.5 initial 30-06 results