Where to go from here? 338 LM

[Bravoman]

So just got back from the range only had 100yrds to play with today next range visit will be at 300yrds.
I did some load development with the 225gr ssst’s from hornady where are some of my results.

Ruger precision 338 Lapua rifle
Powder 7828 SSC
CBTO 2.986
Brass nosler new
Neck turned to .014
Primer pockets uniformed to .131
#1. #2
88.3grs. 88.5
2827 2921
2822 2979
2866 2879

#3 #4
88.9grs 89.4grs
2883 2927
2904 2933
2887 2929

#5 #6
89.8grs 90.5grs
2934 2967
2922 2945
2938 2935

My best group was with load 3
And from load 4 ,5 and 6 seems like I didn’t gain anymore speed so probably not burning all the powder on those loads. I’m thinking of playing with 88.4 to 89.2 see if can get good consistency and probably call it good.

 

[jmorris]

I’d probably move further away, that’s a lot of rifle for 100 yards.

 

[Bravoman]

I’d probably move further away, that’s a lot of rifle for 100 yards.

Yeah next range trip I’ll be set at 300yrds

 

[thump_rrr]

I typically start at 200M with 338LM.
Since you were firing virgin brass I would re shoot the now once fired brass at 200y or 300y again.
Typically I go up in 1% increments (of case volume) for initial testing.
Once I find an area of interest I may tighten it down to 0.7%.
Why are the steps in your powder charge uneven?
#1 88.3
#2 88.5 +0.2
#3 88.9 +0.4
#4 89.4 +0.5
#5 89.8 +0.4
#6 90.5 +0.7

 

[Bravoman]

I typically start at 200M with 338LM.
Since you were firing virgin brass I would re shoot the now once fired brass at 200y or 300y again.
Typically I go up in 1% increments (of case volume) for initial testing.
Once I find an area of interest I may tighten it down to 0.7%.
Why are the steps in your powder charge uneven?
#1 88.3
#2 88.5 +0.2
#3 88.9 +0.4
#4 89.4 +0.5
#5 89.8 +0.4
#6 90.5 +0.7

Because I’m a dummy , the last load was supposed to be 90.2grs but when I noticed that it was at 90.5 I just left it as I had already seated the other 2 rounds and I was 2 grns below max. But for sure will be going to 300yrds next weekend.

 

[Varminterror]

Looking at the groups: there likely is not any significant statistical difference between any of loads 3, 4, 5, or 6, maybe not even statistically significant difference between any of them. Maybe surprising is the horizontal position between 1 & 2 vs. 3 - 6, but it doesn't really appear we have any reliable information in relative vertical position of the groups - there's a little up and down bobbling, but looking like under 1/4", and predominantly within the noise of the larger #1 and #2 groups. So on an OCW or Audette basis, we don't learn anything from the group vertical positions, and from a statistical assessment of mean group radius vs. statistical confidence interval, we likely don't learn anything from the group size either.

Looking at the velocity data, there's some weird stuff going on in the first 3 charge weights, big spreads among the data, suggesting the results will be unreliable, so from a 3rd perspective, we likely don't learn anything from the velocity data. MAYBE we could point at the 89.4-89.8grn span as smaller spread and flat velocity node, but there's too much noise in the earlier data and later data to have too much confidence there. Looking at the spread and SD of each velocity step, we only have Spread = ~1.8xSD to ~2.0xSD, which suggests we really can't rely on the velocity average or stability - the error bars around the average would be quite big, most likely bigger than the spread we're seeing for each point.

The only thing I might observe out of that first set - the first two targets are bigger than anything above them, and the corresponding velocity instability of the first two charge weights is significantly worse than the rest of the set. So personally, I wouldn't rely on charge weight #3 as "best," just because it coincidentally landed in the smallest group. #3 has meth-heads for neighbors down the block, whereas #4 and #5 appear to live in a pretty quiet neighborhood for group size, vertical and horizontal position, and velocity. If I drew any insight at all from this test, it would be 1) I need to redo the test with a better methodology, and 2) I'd expect to see better results in the upper end of the load data.

Personally, I'd reformat the test and follow known, proven practices. Judging by group size, especially at 100yrds, won't deliver what you need for any long range reliability of the load.

How many rounds on the barrel, total? How many rounds on the barrel before the first tests were fired? Did you fire all 3 shots of each charge weight before moving to the next step, or did you shoot one round of each as a string, then repeat? What is your neck tension?

(Plainly, the flatter velocity from 89.4 to 90.5 does not mean you're not burning all of the powder).

 

[Bravoman]

Looking at the groups: there likely is not any significant statistical difference between any of loads 3, 4, 5, or 6, maybe not even statistically significant difference between any of them. Maybe surprising is the horizontal position between 1 & 2 vs. 3 - 6, but it doesn't really appear we have any reliable information in relative vertical position of the groups - there's a little up and down bobbling, but looking like under 1/4", and predominantly within the noise of the larger #1 and #2 groups. So on an OCW or Audette basis, we don't learn anything from the group vertical positions, and from a statistical assessment of mean group radius vs. statistical confidence interval, we likely don't learn anything from the group size either.

Looking at the velocity data, there's some weird stuff going on in the first 3 charge weights, big spreads among the data, suggesting the results will be unreliable, so from a 3rd perspective, we likely don't learn anything from the velocity data. MAYBE we could point at the 89.4-89.8grn span as smaller spread and flat velocity node, but there's too much noise in the earlier data and later data to have too much confidence there. Looking at the spread and SD of each velocity step, we only have Spread = ~1.8xSD to ~2.0xSD, which suggests we really can't rely on the velocity average or stability - the error bars around the average would be quite big, most likely bigger than the spread we're seeing for each point.

The only thing I might observe out of that first set - the first two targets are bigger than anything above them, and the corresponding velocity instability of the first two charge weights is significantly worse than the rest of the set. So personally, I wouldn't rely on charge weight #3 as "best," just because it coincidentally landed in the smallest group. #3 has meth-heads for neighbors down the block, whereas #4 and #5 appear to live in a pretty quiet neighborhood for group size, vertical and horizontal position, and velocity. If I drew any insight at all from this test, it would be 1) I need to redo the test with a better methodology, and 2) I'd expect to see better results in the upper end of the load data.

Personally, I'd reformat the test and follow known, proven practices. Judging by group size, especially at 100yrds, won't deliver what you need for any long range reliability of the load.

How many rounds on the barrel, total? How many rounds on the barrel before the first tests were fired? Did you fire all 3 shots of each charge weight before moving to the next step, or did you shoot one round of each as a string, then repeat? What is your neck tension?

(Plainly, the flatter velocity from 89.4 to 90.5 does not mean you're not burning all of the powder).

Thanks for your input really appreciate it.
I’ll be going out to 300yrds next range trip and be doing 3 shot groups again. So far I have 25 rounds throw the barrel and all were made this same range trip 6 shots were made just before the testing. I fired all 3 shots for each group then moved on to the next. Neck tension is at .002”

First time out to the range with this rifle.

So I’ll probably redo this test start at 88.4grn to 90.4grns in 0.4 increments. Do you think I should go for 5 shot groups?

 

[ArchAngelCD]

Several shooting friends I have load for the 338 LM. They have tried Retumbo, H1000, US896 and Ramshot Magnum. They have found Retumbo and H1000 to be most accurate. The two of them disagree which is best, on prefers Retumbo and the other H1000. They both agree those 2 powders are best.

I have heard Alliant Reloader 33 was specifically formulated for the 338 LM but I don't know anyone who has tried it. Same for the powder you are loading, no one I know has used it.

They feel 7828 is too fast and it looks like your tests prove that out. Your #4, #5 and #6 show no increase in velocity.
They also feel US896 is slightly too slow. (better in the 50 BMG)

Again, I don't own or load for the 338 Lapua Magnum but have been there for the loading and testing of the ammo loaded.with the powders I discussed. (I have shot the rifles too) One is made by Ruger and the other by Accuracy International. (I really like that one!)

 

[N555]

I bet #1 and #2 would open up more than the others at 300yd.
If I was chronograph load developing and saw 40+fps standard deviation over 3 shots, I would abandon that load.
If you are only going to shoot at 300yd or even 600yd I wouldn't waste time turning necks especially with nozler brass. Unless you are running a tight chamber that won't fit standard brass.

 

[AJC1]

I bet #1 and #2 would open up more than the others at 300yd.
If I was chronograph load developing and saw 40+fps standard deviation over 3 shots, I would abandon that load.
If you are only going to shoot at 300yd or even 600yd I wouldn't waste time turning necks especially with nozler brass. Unless you are running a tight chamber that won't fit standard brass.

Inside 500 your not serious in this caliber

 

[Bravoman]

Inside 500 your not serious in this caliber

Yes I agree, this was my first time out with the rifle so was just zeroing my scoop and making sure everything function correctly.
It’s almost a 2 hr drive for my 1k yard range but my plan is to shoot this rifle past 1k most the time.

 

[Varminterror]

Thanks for your input really appreciate it.
I’ll be going out to 300yrds next range trip and be doing 3 shot groups again. So far I have 25 rounds throw the barrel and all were made this same range trip 6 shots were made just before the testing. I fired all 3 shots for each group then moved on to the next. Neck tension is at .002”

First time out to the range with this rifle.

So I’ll probably redo this test start at 88.4grn to 90.4grns in 0.4 increments. Do you think I should go for 5 shot groups?

With so few rounds on the barrel, a LOT is going to change during these early rounds, so you may struggle to get any repeatable results for a while - usually barrels will settle down by ~100-150 rounds. 5 shot groups SHOULD improve reliability of results, but it's not a guarantee of confidence in results. Same deal with shrinking your intervals to regular 0.4grn increments - it SHOULD help you better visualize trends, but with high noise, we might not be able to see much.

Personally, I'd load 3 (or 5), and shoot at 300-600yrds using the chronograph again while shooting those groups either at the same point of aim or at individual points of aim, shooting one round of each charge weight then repeating 3 (or 5) total times - aka, not shooting all shots of a given charge weight as a single string into a group, but rather shooting each incremental charge weight ladder as individual strings. Whether shooting 1 or multiple points of aim, the method is either a Creighton Audette Ladder test or a Dan Newberry Optimal Charge Weight test, coupled with a Satterlee Velocity Curve (really another Audette invention/methodology) to complement the target results.

 

[Weflyfast]

US 869 works best for mine- 24" barrel on a Rem 700 action-
These are 200 yard groups - upper left is fist then dialed in for the second group-

I am really impressed with the accuracy and the performance of the 338 Lapua- amazing cartridge