Does anyone have any good pet loads for a 338 Lapua AI? I have searched around and have found very little discussion on loads for this cartridge. I just recently received my brand new 338 and fire-formed some Lapua brass. I will be loading 300gr Berger Hybrids and 256gr Flat Lines in Lapua brass. Does anyone have experience with this cartridge that is willing to share some good starting loads and what kind of velocity I can expect from a 30" Bartlein?
- Thread starter Sierra’1
- Start date
I have a Proof Research 28" barrel with 37deg improved shoulder and Bore Rider throat.
Lapua Brass, 215m, 102gr of H1000, 300gr Berger.
For my ladder test I didn't see high pressure until 106gr.
Lapua Brass, 215m, 102gr of H1000, 300gr Berger.
For my ladder test I didn't see high pressure until 106gr.
I appreciate the the info. Currently what I have for powder is H1000 so that gives me a good idea of where to start. My chamber is the 40deg shoulder with a custom freebore. I don't recall the exact measurement on the freebore but it is fairly long and gives a lot more usable case capacity.
What kind of velocity are you getting from that load?
What kind of velocity are you getting from that load?
I have not shot it through a chronograph. However I did True my drop on my Kestrel and with the factory 0.822BC its telling me 3175fps.
I am pretty surprised by that number, but the data has been spot on.
I am pretty surprised by that number, but the data has been spot on.
Yes it is, 5.0mil at 1000yds.
I am looking forward to the 330 gr Berger, which should have over a 0.9 BC, and hopefully over 3050 fps.
I am looking forward to the 330 gr Berger, which should have over a 0.9 BC, and hopefully over 3050 fps.
That is awesome. If the improved case will run the 330 gr over 3000 fps it will be a monster for sure. I think I read somewhere that Litz was using that prototype at the King of 2 Miles last year.
I have some of the 256 gr Flatlines that I'm hoping I can get to shoot somewhere around 3300 fps. They have a BC that is very close to the Bergers and should be wicked at 2000 yards if I can get them to shoot. I have been playing with the 121 gr Flatlines in my 6.5 CM but have not been able to find a combination that will shoot anything better then 1.5'' at 100 yards when my 142 gr SMKs will do .2'' when I do my part.
I have some of the 256 gr Flatlines that I'm hoping I can get to shoot somewhere around 3300 fps. They have a BC that is very close to the Bergers and should be wicked at 2000 yards if I can get them to shoot. I have been playing with the 121 gr Flatlines in my 6.5 CM but have not been able to find a combination that will shoot anything better then 1.5'' at 100 yards when my 142 gr SMKs will do .2'' when I do my part.
330??? Jesus I gotta look that up
I'm shooting Flatline 256 GN at 3407 fps using 107.5 GN of RL26 in Petersen brass with Federal GM215M primers with a 4.125 COAL. This is from a 32" Bartlien gain twist (9.5-8) 338 LMAI. Those figures came from a five shot group at 1640 yards with an ES of two, but there had/has to be an elevation error--something--because I used .398BC at 3405 fps when the BC should have been .434. I think. However I was six inches above the rock (1.2 MOA) on the fourth shot. Shot five atomized the target.
400 FPS with 10 more grains of powder? Really?
I messed around with the Flatlines a little but wasn’t super happy with them. I do have some RL33 and RL26 now so I may have to revisit them. My current load that I actually settled on today is 285 Eld-M over 108.7 RL33 in Lapua Brass and Win LRM primers. Looks like is going to be wicked. Tested 8 rounds at 1100 yards. Had right at 5” or just under vertical string and just enough of a wind shift to wreck my windage,
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Indeed: 103 GN RL26 used with the 285 GN Warner Flatline gives me 3174 fps with single digit es and great accuracy.
Reviving thread: Hi, I’m building a 338 Lapua Ackley Improved with a 40 degree shoulder and a Bore Rider throat. I’ve reloaded for Lapuas before but with the Ackley improved what is a good load spot to start load development and where are people finding nodes?
I’m deciding between cutting edge Lazer 275 or 300g Bullets. Single feeding.
Thanks!
I use RL33 because I've plenty of it; 100 GN using Peregrine 275GN & WW mag primers in new Lapua and Petersen (STANDARD LAPUA) brass to fireform. Accuracy was good at 2814fps average. While still fireforming and beginning at 104GN (RL33) and working up to 112GN minimum was 2910 and max was 3126. Clearly not the best combo using 256 Flatlines. Later firings revealed 3300fps using 118GN of RL33--down from 3304 using 117.7GN where I ran out of room for propellant. It seems with projectiles less than say 270GN RL33 loses out to RL26 in both speed and accuracy. I do have Vihtavuori n570, but haven't used it in this barrel. This barrel is chambered for optimum use of the Warner Flatline 256GN and has never fired a cap and core bullet through it. I'm looking to Hammer and Badlands for hunting bullets now.
trying to find a starting load, my build is very similar to yours, 26 inch carbon six barrel, titanium razor action, I plan on shooting 300 grain cutting edge lazers with H1000 powder. The only difference is my Lapua has a 40° shoulder angle vice you’re 37° shoulder angle, I’m guessing it would be smart to start at 99 or 100 grains? Where did you start at?
Sierra1, Any update with your load development process and velocities since you posted a year ago?
Joden, I ended up sticking with 108.7gn of RL33 with a 285 ELD-M. My velocity is running right around 3050 in the 80 degree range and 3020 around 38 degrees. I’m consistently getting SDs of 6 and grouping at 100 yds has been right around .3”. Grouping at 1,200 yds has been very good as well when I have been able to do my part.
Picture is of the first 4 rounds on a completely clean barrel with the low round being the fowler.
I don’t recall what the freebore on my reamer is but it is way past mag length.
Picture is of the first 4 rounds on a completely clean barrel with the low round being the fowler.
I don’t recall what the freebore on my reamer is but it is way past mag length.
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I think you will be fine starting there, I did a ladder test in 0.5gr increments.
What are you doing for trimming your 338 AI cases? Trimming to match the shortest in your lot? My 150 2x fired /annealed cases vary from 2.70 to 2.71 Thanks
While my Lapua & Petersen brass starts out averaging 2.7140 after four firings they've shrunk to 2.6781 on average. I've never had to trim either Lapua of Petersen brass. I have had to trim other manufacturers brass though; my chamber is 2.7280. And yes I wouldn't base any dimensional alterations until handling four times fired brass. Interestingly enough its been accurate (group size) right from the start, though the speed is of course much slower than serious loads that follow. I should mention that I anneal after de-priming--but before sizing--after each firing. I like to think my brass is relaxed, happy, and always ready to send...
@BCX Thank you for the recommendations/feedback. Like other ackleys I have toyed with, they don't seem to grow much, even with relatively warm loads.
For those who were interested my OAL is 3.901. I have held off on trying the flatlines in the 338 because I didn’t have good luck with them in my 6.5 Creedmoor. So fare my best results have been with RL33 and decent result with retumbo. I didn’t have good results with H1000.
Interesting. I've never had good results with H1000--in anything--and I've seriously tried given the experience of so many others. The powders that have worked for me are as follows: 50BMG, RL50, RL33, RL26, US869. The first two are the slowest and most accurate out to say 1300 yards; US869 is the easiest powder to handle (like size 12 shot) and showed its merit over others when shooting a mile or more. However it's one to monitor in temp and elevation changes. The most reliable, speedy, and accurate over a wide span of ranges, circumstances, & conditions--for me anyway--have been RL33 and RL26 in bullets from 256 GN through 300 GN.
338LMAI, how much are you jumping the the flatlines? I had great results with the H1000 in a regular 338LM case with 300 Bergers but I couldn’t get it to work with the increased case capacity of the 338LMAI case. It seems that the slower powders work much better with the heavies in that case.
I started on the lands then went to .020 off, then .017, .015, .012, .010, .008; .012 hands down all around won that show. I was surprised to learn that 285 Flatlines preferred .012 also.
I started out with 300 grain CC for fireforming, and have been using both 300 grain Nosler's and Bergers in the fireformed cases. I do have a couple boxes of 285 hornadys to experiment with, as well as several boxes of 300 grain Sierra matchkings. Maybe I will try solids on the next barrel. Of the bullets mentioned, based on your experiences, does the VLD transition best to transonic, followed by possibly the Hornady 285? I've only stretched my loads to ~ a mile thus far.
Monday was my first shooting 270 gn Badlands Superdozer. They are targets 6 & 7 and the MagnetoSpeed printouts tell the story. I am very pleased and will be running up some loads today to shoot tomorrow. Almost got above freezing yesterday and had the range to myself! I think I should sell that photo on eBay. These are all from previously UNFIRED BRASS and even the Barnes 285s impress me. I use them to "break in" new brass.
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Here's today's results. Check out the difference between RL33 and RL26; it's these shoots that make me think that projectiles of 300 gn and up benefit most from RL33, but between 250 and 285 grains RL26 is tops. I neglected to mention that all shots are fired from the same 338 Lapua Magnum Ackley Improved (the orthodox 40* shoulder) with a 32" Bartlein gain twist (1:9.5-1:8) barrel. Both bullets and barrel are treated with hBN. I'm thinking that 102 grains of RL26 is surely a good hunting load using the "Bad 270 Super D." More triggertime and at longer ranges will be needed; what a laborious time-consuming job... Please don't make me do this...
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I use Lapua and Petersen brass. Never had access to Atlas or ADG if they're making 338 Lapua cases so know nothing about them. I fire form it using 5gn reduced-from-already proven-loads. I'll return to this topic later or you may PM me for a "preview." You might want to do that before you buy and try other than Lapua.
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