I would like to here some experiences on using RL 17 in the 375 H&H with 260 or 270 gr bullets. There is no load data, so I may call Alliant. The burn rate is similar to 4350, so a med range 4350 load may work with RL 17. So fr, I really like the results using it in other cals. Thanks, Daryl.

A good starting load is 75 grains RL 17 with the 270 grain bullets. RL 17 is a great powder for the 375H&H. I use it with 300 grain bullets and it is very accurate and consistent.

Thanks, I will give that a try. The tech guy at Alliant said they had no data and was thinking that RL 17 built pressure too fast, even though it has a similar burn rate to 4350. I still think it should work and I will start low and work up. Daryl.

RL-17 is the new magic powder in QuickLOAD
for the .375 H&H and many other cartridges doodled here lately.
Using the automatic defaults available from QL canned selections,
no monkeying with them by me:

Sierra 300-grain SPBT bullet was used for a propellant table
limited to 62,366 psi and 100% case filling:

RL-17 74.1 grains (97.7% fill) >>> 2656 fps (24" barrel) >>> 62,366 psi (100% propellant burnt)
It is the champ load velocity-wise.

In real life I have found 300-grain Nosler Partition bullets
to produce nearly identical velocities as the same weight Sierra
GameKing, with same loads.

I have used RL-17 in 12GaFH, and charges approaching 200 grains of RL-17
ignited flawlessly with a shotgun primer.
Definitely something special about that powder.
Now I need to see what it does in the other .375s, etc.
Any RL-17 I see on a shelf anywhere gets grabbed ASAP.

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I'm partial to R-17, too.

However, the Quickload data seems to treat the R-17 a little faster than it actually is. I use 101.5 grains R-17 with the 350 TTSX .416" in 416 Rigby without a trace of sign of high pressure. If that continues to hold true for your batches of powder you might need to add a couple of grains in order to reach the predicted velocity and pressure levels of QL.

I love RL-17 and use it almost exclusively in my 9.3x62 and get more velocity and less pressure than any other powder I have used. Same for the 30-06 and especially with 200 gr. Noslers...My next venture with RL-17 will be with my long throated, long magazine 7x57 as it works so well with H414, so then I belive RL-17 may work great.

However, with the .375 H&H I prefer to load it down with 300 gr. or 350 gr. bullets to 2500 and 2400 FPS, for DG use and after testing loads a 100 to 150 FPS faster at 300 yards the difference was less than nothing, so I remain at those velocities for all my hunting with the 375 and many powders will do that..I mostly use RL-15 and IMR-4064..

I use a lot of RL-15, RL-17, RL-19 and RL-22, Alliant is great powder..Promblem is availability this last year, hopefully it will loosen up..

416Tanzan,

Good point. There seems to be a lot of variability with Alliant Reloder powders from lot to lot,
as documented by Doc M at MIB in Conway, SC.
Old RL-10x as when first released a few years ago was much faster than latest lots.
Rusty McGee and I noted the same findings in testing and retesting 400 Whelen loads, with old versus new RL-10x.
A lot of people have noted similar variability with RL-15.
I was hoping RL-17 would be different, more consistent from lot to lot.
Lawndart tells us that Alliant powders are "seconds" lots from Bofors, repackaged for sale here as Reloder powers.
That would explain the variability.
That is mitigated by using 8-pound jugs.
You change lots less often, and have to work up a new load less often.

The RL-17 is dense, there is romm for more of it in the .375 H&H, and with a slower lot, yes, use more.

H4350 beats RL-17 by a small margin in the .375 Weatherby, according to QL: Higher velocity with lower pressure.
H4350 has long been my powder for the .375 Wby, proven performance.
It is also Saeed's choice in the .375/404 Jeffery, proven there too.
Good to see some real-life validation of QuickLOAD there too.

9.3x62 and .375 H&H seem to be similar in powder choice, as Ray suggested. RL-17 shines there too.

I really like the Alliant Reloder powders, though they are the red-headed stepchild compared to Hodgdon Extreme line of powders.
I go to an Alliant ReLoder powder when they can better results from a Hodgdon Extreme powder for some reason.

quote:

Originally posted by RIP:
416Tanzan,

Good point. There seems to be a lot of variability with Alliant Reloder powders from lot to lot,
as documented by Doc M at MIB in Conway, SC.
Old RL-10x as when first released a few years ago was much faster than latest lots.
Rusty McGee and I noted the same findings in testing and retesting 400 Whelen loads, with old versus new RL-10x.
A lot of people have noted similar variability with RL-15.
I was hoping RL-17 would be different, more consistent from lot to lot.
Lawndart tells us that Alliant powders are "seconds" lots from Bofors, repackaged for sale here as Reloder powers.
That would explain the variability.
That is mitigated by using 8-pound jugs.
You change lots less often, and have to work up a new load less often.

The RL-17 is dense, there is romm for more of it in the .375 H&H, and with a slower lot, yes, use more.

H4350 beats RL-17 by a small margin in the .375 Weatherby, according to QL: Higher velocity with lower pressure.
H4350 has long been my powder for the .375 Wby, proven performance.
It is also Saeed's choice in the .375/404 Jeffery, proven there too.
Good to see some real-life validation of QuickLOAD there too.

9.3x62 and .375 H&H seem to be similar in powder choice, as Ray suggested. RL-17 shines there too.

I really like the Alliant Reloder powders, though they are the red-headed stepchild compared to Hodgdon Extreme line of powders.
I go to an Alliant ReLoder powder when they can better results from a Hodgdon Extreme powder for some reason.

There are two differences with Rel 17 and the other Reloder line.

The first, from what I hear, is that the Reloder-17 is made by a Swiss company, not Swedish Bofors. So the rumors about Swedish seconds or the problem with Rel-10x doesn't apply. It's comparing apples and oranges.

Secondly, the three different lots of Rel-17 that I have used over the past four years have been remarkably and reliably consistent. In particular, where I have tested them against H4350 the Rel-17 powder always came out on top. As you have noted, Rel-17 is a dense powder and a person can get more Rel-17 into a space than H4350. In 338WM I've gone with R-17, especially with the 225gn.TTSX, since the TTSX is a longish bullet and the powder space in the 338WM is limited. I could probably find a way to use H4350 in the 416Rigby, since I haven't hit a maximum load yet. But the Rel-17 has been working so well, that we don't have the need.The case fill of 101.5 gn. Rel-17 and the 350 TTSX is about optimum. I don't remember if it always 'cruches' but if so, it is a light crunch, a light compression.

So by all means test the R17 in the 375H&H. The 375Ruger would be even better with its very slight capacity increase. The problem with Quickload predictions and Rel-17 would seem to be that Quickload is using a datum that is just a tad faster than reality. Since I don't have Quickload, I can't answer about how to tweak it or whether some of the 'constants' like the mysterious "0.5" factor needs to be shifted to 0.49 or 0.51, etc.

416Tanzan,
You say RL-17 is Swiss and not subject to the Swedish Bofors seconds deal of the other RL powders: That is good to know.
I will be hoping to check out RL-17 in many cartridges.

It must be that QuickLOAD is way off on the powder thermodynamic specs for RL-17.
Tweaking the case-shape weighting factor would be insignificant compared to the magnitude of your difference in the .416 Rigby versus QuickLOAD.

Definitely a shoot-and-see proposition with RL-17 load velocity predictions ... starting with QL predictions of around 50-55K psi and work up.

Here is a great article about Swiss-made RL-17, thanks for the headsup:

http://www.6mmbr.com/reloder17.html

"Speed Beyond All Expectations...
Here at Accurateshooter.com, we've done a lot of load testing, with a wide selection of cartridges and powders. Generally when a newly-introduced powder offers even a slight edge in velocity or accuracy, that's newsworthy. In the case of Alliant's new Reloder 17 (RL17), we were truly amazed by the enhanced velocities this powder offers compared to other propellants ..."
"... How does RL17 produce so much added speed? There are two main reasons--unique burn properties and high load density. In its chemical properties, RL17 is like no other powder available in the U.S. market. Made in Switzerland by Nitrochemie, RL17 has a unique burn-rate controlling chemical that penetrates all the way through the kernels. Other common extruded powders have only a surface coating. Reloader 17's unique penetrating burn-rate regulator smooths out the pressure curve, allowing RL17 to maintain high energy for a longer period of time ..."

Maybe with the special retardant method it is very temperature stable too?
And such a high-density, multi-use burn rate to boot!

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And thank you for the articles. They are helpful.

Yes, I expect that R-17 is fairly temperature stable and so I have read somewhere from what seemed a reliable source (Alliant?). The articles help us to separate internet 'urban legends' from fact.

In any case, our 338WM and 416Rigby currently in Tanzania are shooting Rel-17 loads, happily and sometimes in extreme heat. I've still got a couple of cans of the stuff in Calif for testing in another 416 whenever I get the chance. On primers, I've only used Fed215Match in the Rigby but both Fed215M and Rem 9.5Mag in the 338WM. As far as I can tell, the 338WM R17 powder load sizes are equally happy with either primer. The difference in size is considerable. The Rigby loads are 101.5 R17 with the 350gn TTSX and 102.5 R17 with the 350 gn TSX. The 338WM is only 71 gn R17 with the 225gnTTSX (caution on this last load: the 338 rifle in question has a large-cut chamber and lets the case expand to .5165" on top of the belt without getting sticky. Other rifles may want to stop at 69 or 70 grains, and the Alliant database with Speer bullets only uses 67.5 gn[something akin to the Quickload patterns].)