Problems with RL25 in 338LM?

[Redhook]

Just started working up loads for my AI AWSM at the beginning of the year. I bought both H4831SC and RL25. Started with the H4831SC and have had great results. Consistent velocities and low SD for accuracy groups. No load tested over MOA with better groups sub 1/2 and the best load at .350". Best load is 250gr Scenar over 89.8gr at about 2935fps.

I loaded up 40rds of RL25 this past weekend in groups of 5 from 90.5gr to 94.0gr, 0.5gr increments. I couldn't get a group to shoot under MOA. The SD did finally start to drop into single digits for the 93.5 and 94.0 groups at about 3000fps, but they were still big groups. Could the powder be the problem? Seems like most people were satisfied with RL25.

I have to wonder if there is a mechanical problem going on elsewhere as well.

 

[ChrisGarrett]

Re: Problems with RL25 in 338LM?

I'm just throwing something out here, but RL-25 is a slower powder and probably better suited to the 300s and not the 250s. I know you can throw any of the slower and faster/slower powders into the case and get the tips down range, but some do better than others. Also, maybe your stick just doesn't like the impulses you're getting? Start switching things around.

For the 250s in my 1:12 Sako, it's 4831sc and VV-165 for 90% of the time with the 250 Scenars and SMKs, but I've had very good groups with VV-170 and to a lessor extent, H-1000. I have just about a pound of RL-25, but I've slowed down shooting that weapon at my local 100 yd range.

Maybe try some VV-165 or VV-170 and see? RL-25 is generally a nuts on powder for the 338LM. Many shooting the 250s report good results, so your experience is not the norm.

Chris

 

[desertHK]

Re: Problems with RL25 in 338LM?

My best group for the AIAWSM is 94.5 grains of RL25 using the 250 scenars.

 

[madmax56]

Re: Problems with RL25 in 338LM?

How far off the lands are you setting your projectiles? I use 94grns flat of RL25 that are about kissing the lands and getting some good results. Are you using magnum primers?

There are so many factors involved.


Good luck and please keep us up with what you're up to with the loads.

 

[barry5]

Re: Problems with RL25 in 338LM?

I have used several powders in my 338LM and found that Retumbo and RL19 gave the best results at least with the 250 grainers. I over looked RL19 for a while but the test target that came with my rifle gave the recipe of what they used for brass, primer, bullet and powder and that is what they used.

 

[Redhook]

Re: Problems with RL25 in 338LM?

Thanks for the info guys. To fill in the blanks, it's Lapua brass, Fed 215M primers, loaded to .005" off the lands.

Desert, what velocity are you getting with the 94.5gr? I didn't show any pressure signs at 94.0 but it still seems hot to me.

To rule out mechanical problems I guess I'll do a side by side with my best 4831SC and maybe the upper end of the RL25 range.

 

[Downzero]

Re: Problems with RL25 in 338LM?

If you didn't show ANY signs of pressure at 94 grains, half of a percentage increase in powder charge is not going to be too hot.