H4831SC & 338 Lapua

[shoots_5]

Got up at 5am and drove for an hour to see if I could get a coyote this morning but no such luck.... Also had some experimental loads to play with so after a few unsuccessful stands I set up a target at 100 yards and shot for some groups using H4831SC and Hornady 285gr BTHP Match bullets. Thought I'd try something other than H1000 or Retumbo to see if I could find some really good accuracy.

I started at 80 grains and loaded 3 each going up in 1 grain increments up to 83 grains. Groups got tighter with each subsequent load. 81 grains yielded an average velocity of 2525fps, 82 grains Avg 2553 with about an inch group, and then there was 83 grains that stacked 3 rounds on top of each other all touching straight up and down. All groups shot prone off the bipod.

Velocity was 2592, 2593, 2599....I think I have found something to play with. Velocity obviously isn't as good as I would hope, but I had zero pressure signs so I still have some room to work up and the way the groups were shrinking with each step up in powder I'm hoping the trend will continue! Of course temperature was 38 degrees so the velocity might perk up a tad on a slightly warmer day. I always like to get as much velocity as I can, but a very wise man once told me, "a slow hit is always gonna beat a fast miss!"

Anyway, it was nice to get out and burn some powder and even get a nice group out of the deal. If nothing else I've got some more tinkering to do now. If I can keep that kind of accuracy and raise the velocity up to about 2650-2700 I think I would be plenty happy with it!

 

[JD338]

Nice! Man, your 338 Lapua is a shooter.

JD338

 

[DrMike]

I'm a little surprised that the velocities are that tight. What were your SDs? Accuracy is certainly present.

 

[338winmag]

After testing 5 different powders and a gazillion seating depths with those powders, I decided to try H4831sc for my 338 Win Mag and Nosler 225 ABs.

I am sold on this powder. Like you, I found accuracy and FPS to be extremely consistent all the time .... but I did sacrifice about 50 FPS with the powder.

Nice shooting by the way!
338 Win Mag

 

[Desert Fox]

I tried the IMR version as a fire forming load for my 338 Lapua Improved using Hornady 250 grain BTSP bullet. I remember the load was scary accurate. I have no problem popping clay pigeon at 525 yards with it. Not sure what the velocity was but it could have easily equaled the 338 Winchester load.

 

[shoots_5]

DrMike, SD's were very low. 81gr load was SD 3.46 ES 7.38, 82gr was SD 15.52 ES 29.13 and I forgot to change strings on my chronograph for the 83g load but listed the velocities in the post above.

I've always had extremely good accuracy using imr 4831 in my 300 H&H but had never used the hodgdon version before. Seems to also be a very accurate powder! I'm going to load up a 5 shot string at the 83gr load and see if accuracy repeats and get some more chrony data, and also load a few up at 84 & 85 grains and see if I can find the max load for my rifle and try and gain a bit more velocity out of it. I was gaining about 30-40fps per grain in the previous loads so if I can get to 85 grains hopefully that will put it near 2700fps.

I know it's listed as one of their extreme powders but anyone have any experience with this powder in different temps? Is it fairly stable or use caution if it's 30 degrees warmer?

 

[DrMike]

I'm still surprised, and more so perhaps, at the lack of velocity increase with the reasonably significant increase in charge. The excellent SDs only serve to compound the anomaly. I would say that you have definitely plateaued at a charge of 80 or 81 grains of powder, with the suggested excellent SD. Because of apparently increasing SD without an obvious increase in velocity, I'd say that you have definitely peaked out. The next change is a very big increase in velocity with aberrant increase in SD due to excessive pressure. Your accuracy is excellent; obviously you have found the node for this rifle. All very interesting. I don't believe you will have any difficulty shooting that load in 30 degree weather, especially is you take the normal precaution of not leaving your cartridges lying around in the direct sunlight all afternoon.

 

[usmc 89]

i use h4831 in my 6.5-284 and 30-338 win and have never had any problems with it when the weather gets warm or cold the 6.5-284 is loaded a grain over recommended max and still no pressure problems when the temp gets over 80. i have also noticed that when you get to the point of excessive pressure h4831 is a bit more subtle and forgiving than some of the other powders i have used. re 17 not so much, i still have a lawton 7000 extractor laying somewhere in south eastern wisconsin.