Too bad this will be used for load dev.

[tabascoz28]

load.jpg

Any tips on 338LM using 300g Scenars or 230 Hornady ELD?

[ar15barrels]

Post the barrel length, measured case capacity from a fired case in grains of water and OAL with each bullet.

[tabascoz28]

27" barrel

base to Ogive is 2.975

I've never done the water capacity measurement method before. I think Ill try the tried and true book loads and what other says around the net. Just a reloader, not a pro yet, maybe ever...

[ar15barrels]

base to Ogive is 2.975

Base to Ogive does not help.
Need to know overall length of the loaded cartridge with each bullet.

[tabascoz28]

Hodgdon and Lyman have very different load min maxes for the same bullet.

Lyman is 83-88
Hodgdon is 85-94c

[ar15barrels]

Hodgdon and Lyman have very different load min maxes for the same bullet.

Lyman is 83-88
Hodgdon is 85-94c

Different guns.
Probably different OAL's and case capacities.

If you told me YOUR OAL's and CASE CAPACITY, I can run you powder charge simulations for your specific bullets.

Here is a 300 Scenar at 3.6" OAL with Retumbo using the standard 338 lapua case capacity model:

Cartridge          : .338 Lapua Mag.
Bullet             : .338, 300, Lapua Scenar GB528  G7
Useable Case Capaci: 89.459 grain H2O = 5.808 cm³
Cartridge O.A.L. L6: 3.600 inch = 91.44 mm
Barrel Length      : 27.0 inch = 685.8 mm
Powder             : Hodgdon Retumbo

Predicted data by increasing and decreasing the given charge,
incremented in steps of 0.575% 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

-05.7   99    82.00   2490    4131   45088   9955    100.0    1.631
-05.2  100    82.50   2505    4180   45981   9981    100.0    1.616
-04.6  100    83.00   2520    4230   46892  10007    100.0    1.602
-04.0  101    83.50   2534    4279   47823  10033    100.0    1.587
-03.4  101    84.00   2549    4328   48776  10058    100.0    1.573
-02.9  102    84.50   2564    4378   49746  10083    100.0    1.559
-02.3  103    85.00   2578    4428   50743  10108    100.0    1.545
-01.7  103    85.50   2593    4478   51761  10133    100.0    1.531
-01.1  104    86.00   2607    4528   52799  10157    100.0    1.518  ! Near Maximum !
-00.6  104    86.50   2621    4578   53861  10181    100.0    1.505  ! Near Maximum !
+00.0  105    87.00   2636    4628   54949  10204    100.0    1.491  ! Near Maximum !
+00.6  106    87.50   2650    4679   56047  10228    100.0    1.478  ! Near Maximum !
+01.1  106    88.00   2665    4729   57195  10251    100.0    1.465  ! Near Maximum !
+01.7  107    88.50   2679    4780   58357  10274    100.0    1.452  ! Near Maximum !
+02.3  107    89.00   2693    4831   59547  10296    100.0    1.439  ! Near Maximum !
+02.9  108    89.50   2707    4883   60760  10318    100.0    1.427  !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 3% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 3% relative to nominal value:
+Ba    105    87.00   2670    4750   58803  10061    100.0    1.452  ! Near Maximum !
Data for burning rate decreased by 3% relative to nominal value:
-Ba    105    87.00   2596    4490   51316  10367    100.0    1.533

[tabascoz28]

OALs with the Hornady gauge full stop.

300g scenar 3.629
250 interlock 3.48
230 eld 3.55

[tabascoz28]

4 fired cased each weighing about 317.3 grains
Filled each with aprox the same amount to the top

avg 436g total.
avg 118.7 grains of water weight.

[ar15barrels]

And for comparison, here is a 300gr Woodleigh bullet in the same 27" barrel:

Cartridge          : .338 Lapua Mag.
Bullet             : .338, 300, Woodleigh SN WeldCore 58
Useable Case Capaci: 95.411 grain H2O = 6.195 cm³
Cartridge O.A.L. L6: 3.600 inch = 91.44 mm
Barrel Length      : 27.0 inch = 685.8 mm
Powder             : Hodgdon Retumbo

Predicted data by increasing and decreasing the given charge,
incremented in steps of 0.549% 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

-05.5   97    86.00   2526    4251   46316  10496    100.0    1.611
-04.9   98    86.50   2540    4297   47187  10524    100.0    1.598
-04.4   98    87.00   2554    4345   48065  10551    100.0    1.584
-03.8   99    87.50   2568    4392   48980  10579    100.0    1.571
-03.3  100    88.00   2581    4439   49903  10606    100.0    1.557
-02.7  100    88.50   2595    4487   50847  10633    100.0    1.544
-02.2  101    89.00   2609    4534   51809  10660    100.0    1.531  ! Near Maximum !
-01.6  101    89.50   2623    4582   52793  10686    100.0    1.519  ! Near Maximum !
-01.1  102    90.00   2636    4630   53794  10712    100.0    1.506  ! Near Maximum !
-00.5  102    90.50   2650    4678   54819  10738    100.0    1.493  ! Near Maximum !
+00.0  103    91.00   2664    4726   55867  10764    100.0    1.481  ! Near Maximum !
+00.5  103    91.50   2677    4775   56935  10789    100.0    1.468  ! Near Maximum !
+01.1  104    92.00   2691    4823   58025  10815    100.0    1.456  ! Near Maximum !
+01.6  105    92.50   2704    4872   59140  10839    100.0    1.444  ! Near Maximum !
+02.2  105    93.00   2718    4920   60278  10864    100.0    1.432  !DANGEROUS LOAD-DO NOT USE!
+02.7  106    93.50   2731    4969   61441  10888    100.0    1.420  !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 3% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 3% relative to nominal value:
+Ba    103    91.00   2697    4846   59849  10622    100.0    1.442  ! Near Maximum !
Data for burning rate decreased by 3% relative to nominal value:
-Ba    103    91.00   2625    4591   52121  10924    100.0    1.522  ! Near Maximum !

Notice how much different the pressures are for the same charge weights?
That's because the bullets are different lengths which creates a different usable case volume.

[tabascoz28]

Ahh, so the program knows what the bullet profiles are and takes away or adds usable capacity for its calculations. Interesting!

[ar15barrels]

300g scenar 3.629
250 interlock 3.48
230 eld 3.55

avg 118.7 grains of water weight.

Your chamber has a lot more case volume than the standard Quickload model.

Cartridge          : .338 Lapua Mag.
Bullet             : .338, 300, Lapua Scenar GB528  G7
Useable Case Capaci: 100.164 grain H2O = 6.504 cm³
Cartridge O.A.L. L6: 3.600 inch = 91.44 mm
Barrel Length      : 27.0 inch = 685.8 mm
Powder             : Hodgdon Retumbo

Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.099% 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

-11.0   87    81.00   2341    3651   35448  10160     99.9    1.844
-09.9   88    82.00   2369    3739   36719  10230    100.0    1.819
-08.8   89    83.00   2397    3827   38038  10294    100.0    1.787
-07.7   90    84.00   2425    3916   39407  10356    100.0    1.757
-06.6   92    85.00   2452    4005   40828  10417    100.0    1.729
-05.5   93    86.00   2479    4095   42301  10477    100.0    1.701
-04.4   94    87.00   2506    4184   43833  10536    100.0    1.673
-03.3   95    88.00   2533    4275   45424  10595    100.0    1.645
-02.2   96    89.00   2560    4366   47076  10653    100.0    1.619
-01.1   97    90.00   2587    4457   48793  10710    100.0    1.592
+00.0   98    91.00   2613    4548   50577  10765    100.0    1.567
+01.1   99    92.00   2639    4641   52434  10820    100.0    1.542  ! Near Maximum !
+02.2  100    93.00   2666    4733   54364  10874    100.0    1.517  ! Near Maximum !
+03.3  101    94.00   2692    4827   56371  10928    100.0    1.493  ! Near Maximum !
+04.4  102    95.00   2718    4920   58461  10980    100.0    1.469  ! Near Maximum !
+05.5  103    96.00   2744    5015   60636  11031    100.0    1.446  !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 3% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 3% relative to nominal value:
+Ba     98    91.00   2648    4669   54153  10626    100.0    1.525  ! Near Maximum !
Data for burning rate decreased by 3% relative to nominal value:
-Ba     98    91.00   2574    4413   47217  10923    100.0    1.611

Now, this is NOT tested load data as it is derived from your measurements.
You can't compare your 27" barrel to published load data derived in 24" test barrels so comparing velocity to real published data is useless.

What you can do is go load a few rounds per the loading manual recommendations and chronograph them and then compare the velocities you measure to the quickload simulation in this post.
If you find the closest velocity in the simulation to your actual results, then the pressure of that load should be very close to whats shown on that same line as the velocity.
There might be big differences in the charge weight, but that will be from the differences between your actual chamber vs the model.
The model can be fine tuned to match your actual gun and then very close results can be expected.

If it so happens that you try 86gr and you get close to 2479fps, then your gun is a VERY close match to Quickload simulation.
If you try 86gr and get a higher velocity, then your chamber is smaller and the case capacity needs to be adjusted smaller in the model.
If you try 86gr and get a lower velocity, then your chamber is bigger and the case capacity needs to be adjusted bigger in the model.

[ar15barrels]

Ahh, so the program knows what the bullet profiles are and takes away or adds usable capacity for its calculations. Interesting!

Yes.
That's exactly what it does.

[tabascoz28]

Thank you very much sir. Hopefully I'll find something usable and one day more of that powder for fine tuning.