338 Lapua Reloading Recomendations

bonrox

Private
Minuteman
Feb 17, 2019
10
2
I am just starting to reload my 338 lapua and have decided on some things. I am looking for any feedback you all can offer.

The rifle is a Masterpiece Arms, 1:10 twist, 26" barrel, 3.850 Acculite magazine. The barrel is marked with Federal GMM 250 grn. It has a Stiller bolt action (3/4).
I have been using 250 grn Hornady Match BTHP, about 250 rounds so far.

I am going to order the following equipment:
RCBS Rock Chucker Supreme
RCBS Chargemaster lite
RCBS Dies
RCBS Case trimmer
I do have OAL measuring stuff (Hornady)

The load materials I am thinking about is:
Hornady 250 grain BTHP bullets
Alliant Reloader 33
Once shot Hornady cases I have
GM215M Primers

The only load data I have is 103.5 grain for 250 grain Sierra Match King and 99.3 for a 250 grain Nosler Partition.

Any suggestions would be welcome.
 

wilson1911

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Aug 6, 2012
577
599
Oklahoma
retumbo
redding s bushing die
home brew case lube or imperial
shoot the hornady, but save for a blue box

Cartridge : .338 Lapua Mag.
Bullet : .338, 250, Hornady BTHP 33361
Useable Case Capaci: 95.317 grain H2O = 6.189 cm³
Cartridge O.A.L. L6: 3.681 inch = 93.50 mm
Barrel Length : 26.0 inch = 660.4 mm
Powder : Alliant Reloder-33

Predicted data by increasing and decreasing the given charge,
incremented in steps of 0.21% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms

-02.1 103 97.90 2771 4261 48493 12548 95.5 1.431
-01.9 103 98.11 2778 4284 48884 12577 95.6 1.426
-01.7 103 98.32 2785 4307 49271 12604 95.7 1.421
-01.5 103 98.53 2793 4329 49678 12632 95.9 1.415
-01.3 104 98.74 2800 4352 50082 12659 96.0 1.410
-01.1 104 98.95 2807 4375 50488 12686 96.1 1.405
-00.8 104 99.16 2815 4398 50899 12713 96.2 1.399
-00.6 104 99.37 2822 4421 51313 12739 96.3 1.394
-00.4 104 99.58 2830 4444 51732 12765 96.4 1.389
-00.2 105 99.79 2837 4468 52155 12791 96.5 1.384 ! Near Maximum !
+00.0 105 100.00 2844 4491 52581 12816 96.6 1.378 ! Near Maximum !
+00.2 105 100.21 2852 4514 53012 12841 96.7 1.373 ! Near Maximum !
+00.4 105 100.42 2859 4538 53449 12866 96.8 1.368 ! Near Maximum !
+00.6 106 100.63 2866 4561 53887 12890 96.9 1.363 ! Near Maximum !
+00.8 106 100.84 2874 4585 54329 12914 97.0 1.358 ! Near Maximum !
+01.1 106 101.05 2881 4608 54779 12938 97.1 1.353 ! Near Maximum !

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba 105 100.00 3032 5102 66830 12694 100.0 1.250 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 105 100.00 2596 3741 41087 11976 87.3 1.542
 

cperazza

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Minuteman
  • Mar 14, 2014
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    Shreveport/Bossier, LA
    Caliber: 338 Lapua Magnum
    Action: TAC338
    Barrel: Brux 29" / 9.5T
    Brake: TBAC 338BA Brake
    Suppressor: TBAC 338BA

    Bullet 1: 300 gr Bergers OTM Hybrids
    Brass: Lapua Brass
    Primer: CCI250
    Powder 1: H1000 / 92 gr
    Velocity 1: 2,934 fps / 59°F
    Elevation: 1,500-1,600' and 2,450'
    Farthest shot: 3,135 yards
    OAL/Ogive: 3.864"/2.990"

    Bullet 2: 254 gr MTAC Cutting Edge
    Brass: Lapua Brass
    Primer: CCI250
    Powder 2: H1000 / 98 gr
    Velocity 2: 3,255 fps / 59°F
    Elevation: 1,500-û' and 2,450'
    Farthest shot 2,630 yards
    OAL/Ogive: Load to seal band

    Bullet 3: 300 gr Bergers OTM Hybrids
    Brass: Lapua Brass
    Primer: CCI250
    Powder 3: Retumbo / 94 gr
    Velocity 3: 2,887 fps / 59°F
    Elevation: 2,450'
    Farthest shot: 451 yards/0.67" Group
    OAL/Ogive: 3.864"/2.990

    Accuracy: Sub .5 MOA
    Marks: Faint ejector mark

    *Note: As with all loads start 10% lower than the indicated loads above.
     
    Last edited:

    towerofpower93

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    Jul 11, 2010
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    OP, I have that exact same rifle from MPA and would definitely suggest using that Hornady OAL tool and ogive measuring kit with anvil so you can see at what CBTO/OAL your specific bullets are touching the lands and can seat further or closer to them as necessary.

    Seems these barrels were throated for the stubbier 250gr SMK, which leads to the newer VLD and tipped bullets contacting the lands well before the 3.850" CIP max length.

    I found my rifle had the bullet contacting the rifling at a CBTO measurement of 2.750" and OALs of 3.645” and 3.605” for the 250gr Berger Hybrid and 285gr Hornady ELD-M, respectively.

    I'll also second Retumbo. Hard to find online at the moment, but it ended up giving me a very consistent velocity plateau for each bullet during an initial velocity ladder and is giving nice groups and acceptable ES/SD with the Beger and great ES/SD with the Hornady, based on two 10 shot strings of each. I tried RL33, but didn't see an obvious velocity plateau to do further testing from and was told it was somewhat temp sensitive. Retumbo should be more insensitive to temperature swings, due to it being part of the Extreme line of powders.
     

    wilson1911

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    H1000 might be a good choice also since he is going to shoot 250's if he can't find retumbo.
     

    Kadams1563

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  • Feb 13, 2017
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    Listen to Wilson, I have personally seen what his rifles are capable of doing and his .338 was no exception.

    Only thing wrong with his guns are they are built for lefty’s. Lol
     

    Dave62677

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    May 4, 2013
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    if you are single feed, try the Lee neck sizer die. it keeps my case neck runout at .002 or less on my 308 & 338.
     

    Lynn Jr

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    Nov 20, 2011
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    Lapua brass Fed 215 primer 300 grain Berger or Sierra and 90-92 grains of H1000.
    When the 338 Lapua came out there was no such thing as a 338 MatchKing so most of todays reamers have the wrong freebore. Berger then brought out there 338 bullets but a throater and another 0.175 to 0.190 more freebore and those same bullets will shoot much faster and won't be too far inside the case.
     

    bonrox

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    Feb 17, 2019
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    Guys, I so appreciate all of your viewpoints and help. I did find a few pounds of Retumbo and I think that is the way I will go for the powder. I am also going to go with the Hornady 250 BTHPs. The whole reason I am starting to reload, comes down to cost per shot at this point. I will be going for hyper-accuracy at some point, but for right now, I just want to gain some experience at reloading the 338. By the way, the Lapua was a Christmas present, I have a really cool wife.

    20181214_144302a.jpg
     

    Smithcollector

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  • Oct 24, 2009
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    While I really like RCBS as a company and personally use a Rockchucker press, I'd skip their dies and use the Redding competition dies with the bushing sizer and the micrometer seater. I'd also skip their trimmer and use a Wilson
     

    towerofpower93

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    Jul 11, 2010
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    I was able to get some Retumbo at https://www.shydasoutdoorcenter.com/ if anyone is interested.

    Thanks for the heads up.

    Kinda skeezy they only allow 16lbs total of HAZMAT items on a single HAZMAT fee. Thought it was 45lbs under one HAZMAT charge, that recently change?

    Regardless, picked up an 8lb keg of Retumbo and another 8lb keg of H4250 since they had it in stock and I didn't want to piece together 8 x 1lb bottles of other random powders that would just get me deeper into the "opened this bottle for 20rds of testing and never touched again" scenario.

    ETA: found my own answer...guess we are limited to 16lbs per HAZMAT fee, if using industry boxes that hold 2 x 8lb kegs.

    The transportation of NA 3178 Smokeless Powder for Small Arms is subject to the weight restrictions of §173.171, which includes a limit on the maximum weight allowed per package, “The net weight of smokeless powder in any one box (one package) must not exceed 7.3 kg (16 pounds).” Here, the limit of 16 pounds applies to the hazardous material to be shipped and does not include the weight of the packaging.
     

    bonrox

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    Feb 17, 2019
    10
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    Tower, the amazing thing is I have 2 houses, one in Harrisburg Pa and the other in Jacksonville FL. Right now I am in Florida and Shydas is about 15 miles from my other house. So I have to cover the Haz-mat cost to get it down here.