I'm looking to load either 165 grain accubonds or 150 barnes ttsx. I'm shooting a Winchester 70 Extreme Weather with 24" barrel.

Any suggestions for a good powder to start with? Accuracy is more important to me than velocity. Would also like a powder that is not too sensitive to temperature deviations.

I've got Varget, H4350 and IMR 4064 on hand but would be more than willing to pickup another powder if the performance will be better. Little leery about using the 4064 as I've read many reports on it being temp sensitive.

Thanks,
Mike

I am about to load some 180's with H4350.
Same gun. I bought it off a guy here that already had a load looking pretty good. I am just verifying scale calibration and working up to it.
I will let post back with

Ok great. Thanks. From some preliminary research, it sounds like H4350 gives good accuracy but not the best velocity. Which may be what I'm looking for. Plus, it would be nice to stick with H4350 as I use it for my 30-06 and 270.

However, based on Hodgdon's max loads in their data, using 65.5 grains in the 300 wsm with 165 grain bullets, I will only gain about 100 fps over my 30-06 using 59 grains of powder and same bullet. Not so good.

Anyone try the Superformance powder? On paper, it looks amazing but not sure how the accuracy is.

Thanks,
Mike

I've had good results in that bullet weight with RL 17.

Another vote for H 4350. I run 65 gr under a 180 and have played with it under 165's with very good velocity and accuracy.

I tried RL-17 and H4350 with 180's and 168TTSx's, RL was faster buy good bit but I couldn't get the accuracy to click.

The H4350 worked well with both bullets (180 NPT's and 168TTSX) and the accuracy was better, very very good with the TTSX's which is where I ended up.

The RL-17 was fast enough that I think its worth a try especially if you feel the need to get every drop of velocity.

H4350 for 165's
Imr4064 or Superformance for 150's

RL 17 gives me top speed and accuracy with the 165 ttsx.

Anyone try RL 17 with 180gr TTSX?

Have used rl-17 from 150-190 and it has worked in this 300 wsm rifle.
Have to get the book from the shop for the loads but it does make it a pleasure to shoot with all weights.
I really am fond of the 180's in this thing.

I get good accuracy with IMR-4350 and a 150gr bullet, but it is slow. With a 165 and Rl-17, I actually slightly surpass factory velocity with very good accuracy.

I like Rl-17 so much that I bought a 5lb jug just so I wouldn't have to change lots as often. When Superformance first came out I picked up two pounds to try because of the high velocity Hodgdon claimed they were getting. The accuracy was so poor I didn't even bother to chronograph the loads.

You might want to consider Ramshot powders. Hunter would be right up your alley: is pretty insensitive to temp changes according to John Barsness, and would give decent speed, like around 3150 top end with 165's and around 3200 with the Barnes 150's. Another option may be Ramshot Magnum, or Accurate Magpro. I've seen Magpro give impressive velocity, but never much for accuracy out of a few of the short magnums.

The beauty of H4350: it is one of Hodgdon's extreme powders and is not as affected by temperature swings. I've had great success with it in the 300 WSM using 165's and 180's. It's a powder that I've really come to rely on. It also works great in the 30-06 and 338 win mag. Now If only I could find it at the store

H4831

I also have an Extreme Weather in .300 WSM. I shoot 150 gr Accubonds with IMR 4064. Very accurate load and velocity is 3150 fps.

Had a lot of fun working up loads in my Kimber Montana 300 WSM and Tikka. I shot hundreds of loads over a two year period and found that for these particular guns H4350 worked best for accuracy, consistency, velocity for the 150, 165, 168, 180 TSX, 180 Partitions.

IMR 4350, 4064, RL 15,17,19,22, W760, H4831, Varget are the powders I tested. Spent many a day at the range and many an evening stuffing cases. Pages of notes. Was the most extensive, comprehensive testing I have done. Whole lot of fun. Traded the Tikka and kept the Kimber.

H4350, 180 TSX, Winchester case, Kimber 8400, 300 WSM - My Moose Mashin Mix. The 180 TSX loads are compressed. I don't publish how much powder I stuff into that case but H4350 really works best over all for me in this rifle.

YMMV Best to you.
Jim

rl 17 h4350

H4350 should about do it.

I worked on my 300 WSM loads before RL-17 came out, so I haven't tried it yet, but I get excellent accuracy and velocity with RL-19 and 165 gr Interbonds.

And, if it don't try R-22.

H4350- 180gr
Ram Hunter, H4831sc, RL 17 -200gr
H4350- 165gr
H4350,RL 17-150gr

I get little bitty groups in my Kimber with H4350 and 180 Ballistic tips.

I have been pleased with RL17 and 180g NPP's in my EW 300WSM.

In a model 7 I had a while back I settled on IMR 4831 with 180 accubonds. It was plenty quick enough and had great accuracy to boot. I tried the H4350 but I couldn't get the accuracy I was looking for. But that being said the magazine length had me jumping a long ways though. I did try superformance in it as well, yes it as a barn burner, but here again I didn't care for the accuracy.

I get excellent accuracy with 73.5 gr of superformance and 150gr nosler ballistic tips. My gun is a new fn with 24" barrel

Ive had the best luck w/ 2 guns and 3 barrels using R-19. 180 partitions and 168 TSX. Also try this site and threads around it.http://forum.accurateshooter.com/index.php?topic=2238517.0