338 Lapua Improved and 256 Warner Flatline Are One Helluva Combo!!!!

[EXSOCAL]

My newest long range target / match rig is a custom built 338 Lapua Improved built by Triggered Precision in Idaho and holy cow did I find the load it likes. After scouring the internet for 338 Improved data, I did some load development with the 300 Grain A-Tips. What was interesting with these is they grouped better at 200 yards than 100 yards but they were flying at 2960 FPS with 99 grains of Retumbo in fireformed brass into .5 MOA or less at 200 yards, 100 yard groups were around .75 MOA.

Fast forward to last week, I had some 256 Flatlines with the Tubb nose ring and called up Warner to get some starting load data. The dudes were extremely helpful and gave me a lot of good information. Long story short, one quick round of load dev. and I found my load. 102 Grains of H-1000 pushes the 256 Flatline at 3160 FPS with low single-digit SD's, and I've yet to have a group over 1/4". Anyone with an improved 338 should definitely take a look at this bullet / combo. the rest of the recipe includes fireformed and annealed Lapua brass, FGMM mag primers, custom Hornady dies, .002" neck tension, with the slug seated to have the bearing surface / boat tail junction right at the neck / shoulder junction (around .08" jump in my chamber). The rifle has a 31" 9 twist Brux with a Thunderbeast Ultra 338 on the end.

So far I have about 260 rounds through the improved and I'm really liking the cartridge, the gains over a standard Lapua seem to make it worth the effort of fireforming.

 

[secondofangle2]

You guys think that nose ring does anything ?

 

[EXSOCAL]

The theory is the ring is supposed to help maintain bullet stability while the bullet goes through the supersonic / subsonic transition which plays hell on some bullets. I’ve yet to test this out because these are running supersonic from my rifle in these environmental out to 2600 yards and the furthest I can shoot around here is around 2000. David Tubb also offers nose ringed bullets.

I believe there is merit to the theory and it has been validated. I will be shooting a few matches out to 3k yards so I figured why not. So far these bullets have been nothing short of amazing. I took them to a mile yesterday and had great results.

 

[375fan]

OP , what is your barrel length?

 

[EXSOCAL]

Running a 31” barrel.

 

[Dogtown]

the gains over a standard Lapua seem to make it worth the effort of fireforming.

Most definitely.

I’ve been shooting it for about ten years and this is a cartridge that can be pretty hard on brass if you’re pushing it. For me shooting 300s, the difference between 104gr of RL33 and 107gr was brass lasting about twice as long.

 

[EXSOCAL]

Most definitely.

I’ve been shooting it for about ten years and this is a cartridge that can be pretty hard on brass if you’re pushing it. For me shooting 300s, the difference between 104gr of RL33 and 107gr was brass lasting about twice as long.

Mind sharing your rifle specs and load data with the 300’s? I’m curious as to where I’m sitting for velocity compared to other folks.

 

[Dogtown]

I’ve mostly been runnning 36” barrels, which are honestly a bit excessive.

Off the top of my head for various 300s, I used RL33 for many years, but it’s been unobtainable lately. 106.5gr at 3.882” COAL gives me about 3075fps. I’ve gone up to 108gr, but that’s on the raggeded edge in my latest barrel. Ramshot LRT shows a lot of promise as a replacement, but I haven’t done enough testing to say for sure. N570 is also a good option, but it’s a better fit for bullets in the 250-285gr zone.

 

[EXSOCAL]

Thanks for the info @Dogtown much appreciated. Unfortunately all the Reloader powders have been dried up in my neck of the woods for a while so I’m stuck with H-1000 and Retumbo. I may revisit the 300 Gr Berger’s at a later time and see how H-1000 does, but for now this flatline load flat out shoots! Only thing I’m worried about now is brass life, I don’t have any pressure signs at 102 grains of h-1000 and the 256 flatline, but it seems to be right up there.

 

[Dogtown]

Retumbo would be a better choice for 300s, but keep an eye out for Ramshot LRT too.

 

[alonewolf85]

Thanks for the info @Dogtown much appreciated. Unfortunately all the Reloader powders have been dried up in my neck of the woods for a while so I’m stuck with H-1000 and Retumbo. I may revisit the 300 Gr Berger’s at a later time and see how H-1000 does, but for now this flatline load flat out shoots! Only thing I’m worried about now is brass life, I don’t have any pressure signs at 102 grains of h-1000 and the 256 flatline, but it seems to be right up there.

ramshot is solid, im going to list some as soon as i figure out how to again in here