338 Lapua Ladder Tests

[bigdawg86]

So I in a moment of insanity made a firearm trade for a Savage 110 FCP-HS in 338 Lapua Magnum.

Previously the largest cartridge I have reloaded for is 6.5 Creedmoor and am no stranger to ladder testing. Usually, I make .5 grain adjustments on my charges, and make 5 of each, test at 100 yards. Obviously this cartridge takes more than double the powder, so do most make 1 grain increments on their ladder tests? Also would one still advised 5 rounds each charge, or would 3 be sufficient?

I know you don't buy a 338 Lapua because you are trying to shoot cheap, but don't see the need to waste money either.

Thanks!

[Bill Steele]

So I in a moment of insanity made a firearm trade for a Savage 100 FCP-HS in 338 Lapua Magnum.

Previously the largest cartridge I have reloaded for is 6.5 Creedmoor and am no stranger to ladder testing. Usually, I make .5 grain adjustments on my charges, and make 5 of each, test at 100 yards. Obviously this cartridge takes more than double the powder, so do most make 1 grain increments on their ladder tests? Also would one still advised 5 rounds each charge, or would 3 be sufficient?

I know you don't buy a 338 Lapua because you are trying to shoot cheap, but don't see the need to waste money either.

Thanks!

I think, first pass I would probably use 1 gr (roughly 1%) and 3 shots. Once you get a promising spot, maybe step up the granularity a little and sample size. 338LM isn't going to be cheap, most fun things aren't.

[bsumoba]

I would do 1 round, 1 gr increments. load up and shoot this to find your max load that you see pressure.

Then, back out a grain or two and then work with 3 shot groups in 0.5gr increments to find a good powder range.

[bigdawg86]

I would do 1 round, 1 gr increments. load up and shoot this to find your max load that you see pressure.

Then, back out a grain or two and then work with 3 shot groups in 0.5gr increments to find a good powder range.

Would this approach likely find an accuracy node within that "backing out a grain or two"?

Or starting with the wide spread, finding a node-ish then ladder testing maybe a grain up and down be better to narrow it down?

I'm speaking out of pure ignorance when I ask.

Maybe I'll get lucky and have one ragged hole first try...

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[bsumoba]

Would this approach likely find an accuracy node within that "backing out a grain or two"?

Or starting with the wide spread, finding a node-ish then ladder testing maybe a grain up and down be better to narrow it down?

I'm speaking out of pure ignorance when I ask.

Maybe I'll get lucky and have one ragged hole first try...

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Short answer is I think yes. In my opinion, if you are going to shoot a 338 or a long range cartridge, it only makes sense to get around the cartridges max potential. You should be able to find something within the "grain or two" under max charge powder range.

[bigdawg86]

Short answer is I think yes. In my opinion, if you are going to shoot a 338 or a long range cartridge, it only makes sense to get around the cartridges max potential. You should be able to find something within the "grain or two" under max charge powder range.

Makes sense


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[DAW2432]

Speaking from experience....

I would use a baseline of 90.0 grains of Retumbo under a 300g SMK. 2" groups at 880 yards out of the 110BA, which should have a similar barrel. Certainly not on the hot side, but extremely accurate. Standard seating depth, that throat likes jump. The chrono indicated 2680 FPS, and I got about 5-6 loads through each piece of brass before the case head showed severe signs of pre-separation.

I have video of the grouping you'd like to see it. It's impressive.

I tried A LOT of other loads, powders and bullets. That's where I settled, and it has been amazingly accurate.

FWIW, I tried some factory stuff and the shots were absolutely erratic, including Black Hills Match. The load above is probably a good mid-point to work with, going down or up a few grains, usually .5 at a time.

[bigdawg86]

I have 300g Berger OTM tactical, 300g Berger Elite Hunter (side by side looks identical to the OTM) 300g Sierra FMJBT.

The Bergers and other VLD's like the lands or no? How much jump are you talking.

[LynnJr]

Another common load for factory chambers is 90-92 grains of H1000 with a Fed 215 primer Lapua brass and either the 300 grain Berger OTM or the 300 Sierra.
With a factory chamber there is about 0.150 difference in how the heel of the bullet sits in the case neck.
What that means is if you work up a good load for the 300 Grain Sierras and switch to the Bergers you will most likely need another half grain of powder.
Start at 90 grains with the Sierras as long as they will fit in your gun.
One of our better shooters is using Retumbo as well so I would try both.

[bigdawg86]

Using a OAL gauge I was very suprised to see how far the bullets are seated in the cases, even when on the lands.

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[LynnJr]

Factory chambers are set up for 250 grain bullets because Sierra didn't come out with the 300 grain MatchKing until a couple years after the introduction of the 338 Lapua.
The Sierra sits deeper than the 300 Berger that's why the Berger needs more powder.
To get the most out of a standard 338 Lapua you can have it throated longer to take advantage of the cases capacity.
I had my 338 Lapua Improved throated 0.190 longer and it will push a 300 grain bullet over 3100+ fps.

[bigdawg86]

Factory chambers are set up for 250 grain bullets because Sierra didn't come out with the 300 grain MatchKing until a couple years after the introduction of the 338 Lapua.
The Sierra sits deeper than the 300 Berger that's why the Berger needs more powder.
To get the most out of a standard 338 Lapua you can have it throated longer to take advantage of the cases capacity.
I had my 338 Lapua Improved throated 0.190 longer and it will push a 300 grain bullet over 3100+ fps.

That's awesome... And I'm not going to lie, that cartridge looks down right sexy when the bullet it loaded nice and long. Seems like a waste stuffing it so far into the neck.

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[Whiterabbit]

I would do 1 round, 1 gr increments. load up and shoot this to find your max load that you see pressure.

Then, back out a grain or two and then work with 3 shot groups in 0.5gr increments to find a good powder range.

Would this approach likely find an accuracy node within that "backing out a grain or two"?

Or starting with the wide spread, finding a node-ish then ladder testing maybe a grain up and down be better to narrow it down?

I'm speaking out of pure ignorance when I ask.

Maybe I'll get lucky and have one ragged hole first try...

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Starting with the wide range, you might see that your velocity flatline for a range. There's your experimental range.

Or it doesn't, and remains linear. In which case, a grain or two from max is your experimental range.

[LynnJr]

Get a pound of H1000 some Fed 215 Primers and use Lapua brass.
Load 10 rounds at 88 grains to sight in the rifle and foul the well cleaned barrel.
Now load up 3 rounds at 89 three more at 90 three more at 91 and three more at 92 grains.

Go to the range with your well cleaned barrel and fire the ten rounds getting it dialed in.

Let the gun cool down and shoot your 3 shot groups looking for best accuracy.

You really don't need a official ladder Test as this round with a factory chamber has already been thoroughly sorted out.

If you where working with an improved version with an unknown freebore this is where the Ladder Test would really shine.

Do the same thing with Retumbo as well using the powder charges from a known source.