Barnes lists 73.5 grains of IMR-4831 as max. for a 338 Winchester Magnum with 185 gr.

- Can H4831 be substituted directly for IMR-4831?

- Is H4831 better stability in cold weather? (Extreme Powder)

I read some where that the Hodgdon powder is slightly more accurate involving + or - tolerances vs. the IMR powders. It was + - 2% if I remember correctly and IMR was 3%.

h-4831 is slower than imr 4831 - imr 4831 is about halfway between 4350 and h4831

So if I use H4831SC and cram 73.5 gr's into the case, because it is slower, I shouldn have less pressure than IMR-4831 correct?

personally I dont think the average reloader can tell the diffrence 2% v 3%..
What you do need to consider is that they are two diffrent powders and load data should not be substuted for either.
when working with any powder it is always recommended to work up the load in your own rifle.

IMR-4831 is considerably faster than H-4831. In my experience, IMR 4831 is only marginally slower than IMR 4350.

If a load calls for IMR 4831 and you substitute H-4831 on a grain-for-grain basis, you can expect both lower pressures and velocities.

By the way, I load H-4831 almost exclusively in my .338 (the regular cut version, not the SSC, which packs more densely). I think you'll find H-4831 does well with bullets of 200 grains and more, but it will be a bit on the slow side for a 180-185 grain bullet (depending on the bullet -- if it's monometal all bets are off). I don't have any trouble getting 76 grains of H-4831 (regular cut) into a .338 case, so you should be able to get significantly more than 73 grains of the SSC version in the load you are contemplating.

I can't tell you anything about any possible differences in the way the IMR or H versions behave at differing temperatures.

Might want to check into R-17 for the .338 Win Mag. Looks like the thing!

quote:

Originally posted by hivelosity:
When working with any powder it is always recommended to work up the load in your own rifle.

Yes I agree.

Barnes lists 73.5 gr. of IMR-4831 at 104% load density. If I work up a load using H4831SC, I should be able to get a good, safe powerful load with no compression issues.

I asked about RL 17 data, unfortunately there was none by Barnes.

quote:

I asked about RL 17 data, unfortunately there was none by Barnes.

Look on Alliant web-site.

Alliant uses the Speer.

Not sure how they would compare to TTSX regarding pressures.

Just reduce starting load 5% and work up.

P.S. - I shoot R-17 in my .338 W M

quote:

Originally posted by ar corey:
- Can H4831 be substituted directly for IMR-4831?

quote:

No! They are different powders with only the numbers 4831 in common. The new H4831 even differs from the original surplus powder that Hodgdon once sold.

quote:

Is H4831 better stability in cold weather? (Extreme Powder)

I think that "extreme powder" is much ado about advertising and little else. I can't say I've seen any powders that haven't improved over the years, and I can think of none that are bad when used accordingly.

I have got great results in my 280 AI with N560 and heavy bullets like 160 Accubond. The rifles loves IMR 4831 but N560 is even better. H4831 was not as effective.

quote:

Originally posted by Nakihunter:
The rifles loves IMR 4831 but N560 is even better. H4831 was not as effective.

Effective accuracy or velocity?

I am most concerned with accuracy.

I should probably buy more IMR-4350 and be done with it. Never had that powder shoot bad.

As noted, H4831 is slower. Accuracy will vary from rifle bbl to rifle bbl. either can show terrific accuarcy but H4831 can give you higher vel w/ lower pressures. H4831sc is a short cut & will take up about the same volumn as IMR4831. I get better accuracy in my 404j & 338x74K w/ IMR4831. I give up a bit of vel. but in those two, accuracy is better w/ IMR. In my 280, H4831sc gives me the best vel. & accuarcy w/ 140gr-150gr bullets.

quote:

Originally posted by ar corey:

quote:

Originally posted by Nakihunter:
The rifles loves IMR 4831 but N560 is even better. H4831 was not as effective.

Effective accuracy or velocity?

I am most concerned with accuracy.

I should probably buy more IMR-4350 and be done with it. Never had that powder shoot bad.

The rifle shoots almost any bullet / load within 1.5 inches 5 shots at 100 meters. that is adequate hunting accuracy out to 300 meters in my book.

H4831 with 145 & 150 gr bullets gave 100 fps less than Re19, N160, H4350 etc.

I rarely ever get maximum velocities with any of the rifles I shoot as I stop when I reach a very accurate load that is close to max velocity. The pleasant surprise was when using N560 with 160 Accubonds - I got just over 3000 fps and good accuracy. Primer reseating was tight.