Looking for the best all around powders to use in my 300 Win mag. Looking for both accuracy and speed using 165gr -180gr bullets.

4350,any of the three work really well.

I like RL-22 for 180’s. MRP is about he same stuff.

Nosler lists H-4831 as their accuracy load for 200’s. Gonna try some with 200 NPT’s.

DF

Thanks guys. I know there are a bunch of powders that will work but there is always a few that really shine and stand out. With the knew powders that's been developed over the past couple of years it's hard to keep up with what's going on.
Some of the new high energy powders don't give over 95% case fill and that worries me because of delayed detonation while hunting should the powder not be a against the flash hole.
Also some of the new to me powders need to be near max to perform and show inconsistent velocities with large swings for the same powder charge in lower charge weights.
The older stand by powders may be what I'm looking for.
The 165gr-180gr are for hunting so they need to be dependable and accurate.

Kinda like RL-15 in the .375 H&H. There are other, higher performance options, but that one has been so good for so long, few want to change.

RL-22 has been a go to powder for 180's in the .300 Win, maybe not as universally popular as RL-15 in the .375, but widely used.

I have a big jug of MRP, which I also use. It reportedly may be better stuff that RL-22, but I can't tell the difference. They both work well.

Curious that H-4831 is the Nosler accuracy powder for 200's; it's actually a bit faster burning than RL-22. You'd think the heavier bullet would prefer the slower powder.

If you're looking for that 'magic" load, you gotta go with what others have found to work and what their go to combo may be.

DF

Same have been using R22 for awhile. Next loads will be with R16 & R26. as I haven't tried 150s in the 300 so doing so now for grins. R26 usually has the highest or in the top three highest for velocity from 150s to 215s.

DF RE: H4831 it might be as JB and others have written that for some reason a faster powder obdurates better with Partitions. They need an extra kick in the pants sometimes to do their best accuracy wise.

You may be right. Makes sense.

DF

If I was starting from scratch I would look to R26 and R23 unless I had already stocked up on R22. I am going to try these and R16 next time I load 300s.
Here is the best current data https://www.speer-ammo.com/en/reloading/rifle and also the Alliant site has some loads for these powders.

R23 loads close to R22 and has really good temperature stability plus de-coppering agents. R26 usually gets top velocities with bullets heavier than 150 grains. If the R26 loads don't prove accurate try a hotter primer or just start out with magnum primers.

H7828 is good as well as Ramshot Magnum. I find the 300 easy to load for with anything slower than the 4350s.

Tejano;
Thanks for the link I didn't even know Speer had a on line manual.

IMR-4350 has been my go-to for 150-180 grain loads for 30 years or so. Fast with the 150's. Accurate across every rifle I've ever loaded it for in the 180's. It just works.

Had a VERY bad experience with temperature instability from R-22 in a 7-STW. I'll never drop another charge it in ANYTHING.

IMR 4350

RL 22

Burn a fair amount of IMR 7828. My .300 likes it with 150 and 180gr bullets

I have found H4350 to be the best for Me but I would like to try some RL23.......Hb

I agree. 4350 good, and hard to beat. Good choice.

You're worrying too much if you believe over 95% is necessary.

I've been loading my 300Win with H1000 when using 180gr bullets, great accuracy and I have enough to last a while.

It's not my first concern but it does fill the case up when loaded with top loads.

RL26 175gr Barnes LRX 3150fps most accurate in my 300win mag. Never had an issue in cold or hot weather either.

Yours was the fist reply and probably the best answer...

He must have read somewhere on the web that you had to have at least 95% case fill???? I agree with mathman, it's not necessary...

Thanks for all the replies and suggestions. I guess I'm a little old school on the case fill percentage.

It is a good rule of thumb but not a deal breaker. In fact I like loads at 101% just a slight crush fit not sure if it makes a difference but it is supposed to help uniformity. Keeps the bullets from getting jammed backwards too.

RL26, most velocity not as accurate as rest of list. Retumbo, Norma MRP, H1000, RL23.

IMR-4831. 2 3/4 in. to 3 in. groups at 500 yards was always good enough for me.