top of page

Load data for .378 Weath. Mag. + .375 | 285gr | Speer Grand Slam

Recommended Powder(s): ADI AR 2209, Alliant Reloder-19, Alliant Reloder-26, Norma MRP, Rottweil R 905

.378 Weath. Mag. + .375 | 285gr | Speer Grand Slam

Load Specifications

(Use the Personalized Load Calculator below to adjust )

Bullet:
.375 | 285gr | Speer Grand Slam
Manufacturer SKU:
2473
Bullet Weight:
285gr | 18.5g
Bullet Diameter:
0.375" | 9.52mm
Bullet Length:
1.220" | 31.0mm
Caliber:
.378 Weath. Mag. load data
Case Length (l3):
2.913" | 74.0mm
Cartridge Length (C.O.L.):
3.600" | 91.4mm
Seated Depth:
0.533" | 13.5mm
Shank Seated Depth:
0.533" | 13.5mm
Case Capacity:
137.0 Grains of Water | 8.90 cm³
Primer Size:
Large Rifle Magnum (LRM)
Max. allowed Pressure:
63817 psi | 4400 bar
LID:
LID_B6246_C577
Last updated:
2025-01-01

Load data for 146 loads in caliber .378 Weath. Mag. with .375 | 285gr | Speer Grand Slam bullet and 73 powders such as ADI AR 2209, Alliant Reloder-19, Alliant Reloder-26, Norma MRP, Rottweil R 905. The key underlying parameters are shown in the table above.

  • Important Notice: DO NOT go below Minimum Charge or above Maximum Charge unless there are reasons. Since xxlreloading.com has no control over the equipment and components used by the customer and the data used in connection with the website, any responsibility and liability for the results achieved is rejected. Also see our Terms of Service

    Questions regarding the load data: Please read the information in the next tab "Explanations".

  • No data yet

  • We recommend you limit powder range to relevant brands to speed up re-calculation of results

    Use the Personalized Load Calculator to customize loads to your own specific requirements. Find more details in the help section.

    Our default view only displays powders/loads that fulfill certain criteria: Max pressure of a load <=90% of Max. Standardized Pressure. Fill Rate (Min FR): >80% and <100% for rife loads,  >60% and <100% for pistol loads. Min. Propellant Combustion (Min z): >90% for rifle loads , >80% for pistol/revolver loads. Relax these criteria at your own risk to potentially get more powders shown in the load tables.

    .

    Loading_icon.gif

Click on the desired row in the tables below to add a specific load / powder to your Diary and manage there.

Powder
Charge
FR
MaxP
%
V(0)
z
ADI AR 2208
<<locked>>
83%
57087
89%
**46
100%
ADI AR 2209 👍
<<locked>>
94%
57087
89%
**44
99%
ADI AR 2213
<<locked>>
97%
57116
89%
**81
99%
ADI AR 2217
<<locked>>
97%
41466
65%
**92
95%
ADI AR 2225
<<locked>>
97%
36927
58%
**49
97%
Accurate 2700
<<locked>>
84%
57101
89%
**20
100%
Accurate 3100
<<locked>>
97%
56797
89%
**82
100%
Accurate 4350
<<locked>>
88%
57072
89%
**02
100%
Accurate MAGPRO
<<locked>>
97%
56289
88%
**81
97%
Alliant Reloder-16
<<locked>>
90%
57159
90%
**44
100%
Alliant Reloder-17
<<locked>>
85%
57043
89%
**44
100%
Alliant Reloder-19 👍
<<locked>>
94%
57232
90%
**41
99%
Alliant Reloder-22
<<locked>>
97%
56594
89%
**67
99%
Alliant Reloder-23
<<locked>>
97%
54114
85%
**02
100%
Alliant Reloder-25
<<locked>>
97%
46311
73%
**30
100%
Alliant Reloder-26 👍
<<locked>>
94%
57217
90%
**30
100%
Hodgdon H1000
<<locked>>
97%
41466
65%
**92
95%
Hodgdon H414
<<locked>>
85%
57246
90%
**28
100%
Hodgdon H4350
<<locked>>
92%
57406
90%
**85
100%
Hodgdon H4831
<<locked>>
97%
52504
82%
**49
97%
Hodgdon H4831 SC
<<locked>>
96%
57130
90%
**25
98%
Hodgdon Hybrid 100V
<<locked>>
92%
56971
89%
**59
100%
Hodgdon LVR
<<locked>>
87%
56985
89%
**02
100%
Hodgdon Retumbo
<<locked>>
97%
36927
58%
**49
97%
Hodgdon Superperformance
<<locked>>
87%
56956
89%
**64
100%
Hodgdon VARGET
<<locked>>
84%
57087
89%
**46
100%
Hodgdon TrailBoss
<<locked>>
96%
35215
55%
**90
100%
IMR 4064
<<locked>>
84%
57217
90%
**36
100%
IMR 4166 Enduron
<<locked>>
85%
57174
90%
**40
100%
IMR 4350
<<locked>>
90%
57217
90%
**82
100%
IMR 4451 Enduron
<<locked>>
86%
57072
89%
**62
100%
IMR 4831
<<locked>>
93%
56971
89%
**89
100%
IMR 4955 Enduron
<<locked>>
97%
57435
90%
**92
98%
IMR 7828 SSC
<<locked>>
96%
57421
90%
**94
99%
Lovex S065
<<locked>>
87%
57188
90%
**56
100%
Lovex S070
<<locked>>
89%
57043
89%
**76
100%
Lovex S071
<<locked>>
97%
47732
75%
**51
100%
Norma 204
<<locked>>
89%
57377
90%
**22
99%
[Norma 217]*
<<locked>>
97%
32851
51%
**67
94%
Norma MRP 👍
<<locked>>
95%
57174
90%
**04
100%
Norma URP
<<locked>>
89%
57188
90%
**05
100%
Ramshot Hunter
<<locked>>
90%
57203
90%
**31
100%
Ramshot Magnum
<<locked>>
97%
55347
87%
**38
100%
ReloadSwiss RS 14
<<locked>>
97%
36260
57%
**36
100%
ReloadSwiss RS 60
<<locked>>
86%
57014
89%
**61
100%
ReloadSwiss RS 62
<<locked>>
88%
57392
90%
**31
100%
ReloadSwiss RS 70
<<locked>>
89%
57087
89%
**77
100%
ReloadSwiss RS 76
<<locked>>
97%
45150
71%
**72
99%
[ReloadSwiss RS 80]*
<<locked>>
97%
40843
64%
**51
93%
Rottweil R 903
<<locked>>
84%
56898
89%
**43
100%
Rottweil R 904
<<locked>>
93%
57087
89%
**89
98%
Rottweil R 905 👍
<<locked>>
94%
57159
90%
**38
99%
Rottweil R 907
<<locked>>
87%
57101
89%
**59
100%
SNPE Vectan SP 11
<<locked>>
83%
57203
90%
**82
100%
SNPE Vectan Tubal 5000
<<locked>>
84%
57217
90%
**21
100%
SNPE Vectan Tubal 7000
<<locked>>
88%
57087
89%
**20
100%
Shooters World Long Rifle
<<locked>>
87%
57188
90%
**56
100%
Somchem S355
<<locked>>
84%
57130
90%
**40
100%
Somchem S361
<<locked>>
92%
57159
90%
**59
98%
Somchem S365
<<locked>>
91%
57290
90%
**05
100%
Somchem S385
<<locked>>
94%
57334
90%
**08
100%
Vihtavuori N135
<<locked>>
85%
57319
90%
**51
100%
Vihtavuori N150
<<locked>>
89%
57290
90%
**03
100%
Vihtavuori N160
<<locked>>
87%
57145
90%
**69
100%
Vihtavuori N165
<<locked>>
97%
52562
82%
**23
99%
Vihtavuori N550
<<locked>>
86%
57290
90%
**08
100%
Vihtavuori N555
<<locked>>
95%
56826
89%
**28
100%
Vihtavuori N560
<<locked>>
97%
56927
89%
**04
98%
Vihtavuori N565
<<locked>>
97%
48834
77%
**46
97%
[Vihtavuori N568]*
<<locked>>
97%
42337
66%
**67
93%
Winchester 6.5 StaBALL
<<locked>>
88%
57130
90%
**40
100%
Winchester 760
<<locked>>
85%
57246
90%
**28
100%
Winchester StaBALL HD
<<locked>>
97%
50430
79%
**61
100%

Max Load - Barrel Length: 23.60''

Powder
Charge
FR
MaxP
%
V(0)
z
ADI AR 2208
<<locked>>
81%
53374
84%
**94
100%
ADI AR 2209
<<locked>>
81%
37478
59%
**77
95%
[ADI AR 2213]*
<<locked>>
81%
33388
52%
**05
91%
[ADI AR 2217]*
<<locked>>
89%
32314
51%
**65
90%
[ADI AR 2225]*
<<locked>>
87%
27050
42%
**54
90%
Accurate 2700
<<locked>>
81%
51561
81%
**38
99%
Accurate 3100
<<locked>>
81%
33286
52%
**59
96%
Accurate 4350
<<locked>>
81%
44773
70%
**12
100%
[Accurate MAGPRO]*
<<locked>>
84%
35868
56%
**90
90%
Alliant Reloder-16
<<locked>>
81%
43105
68%
**21
100%
Alliant Reloder-17
<<locked>>
81%
49632
78%
**30
100%
Alliant Reloder-19
<<locked>>
81%
37405
59%
**77
95%
[Alliant Reloder-22]*
<<locked>>
81%
33156
52%
**15
93%
Alliant Reloder-23
<<locked>>
81%
31952
50%
**85
99%
[Alliant Reloder-25]*
<<locked>>
81%
27905
44%
**90
94%
Alliant Reloder-26
<<locked>>
81%
34461
54%
**10
98%
[Hodgdon H1000]*
<<locked>>
89%
32314
51%
**65
90%
Hodgdon H414
<<locked>>
81%
50662
79%
**26
99%
Hodgdon H4350
<<locked>>
81%
41191
65%
**07
97%
[Hodgdon H4831]*
<<locked>>
82%
32735
51%
**46
90%
[Hodgdon H4831 SC]*
<<locked>>
81%
34983
55%
**98
91%
Hodgdon Hybrid 100V
<<locked>>
81%
40640
64%
**07
100%
Hodgdon LVR
<<locked>>
81%
47369
74%
**54
100%
[Hodgdon Retumbo]*
<<locked>>
87%
27050
42%
**54
90%
Hodgdon Superperformance
<<locked>>
81%
45832
72%
**80
99%
Hodgdon VARGET
<<locked>>
81%
52982
83%
**80
100%
Hodgdon TrailBoss
<<locked>>
92%
32938
52%
**44
100%
IMR 4064
<<locked>>
81%
52431
82%
**67
100%
IMR 4166 Enduron
<<locked>>
81%
51097
80%
**48
99%
IMR 4350
<<locked>>
81%
43337
68%
**46
98%
IMR 4451 Enduron
<<locked>>
81%
49429
77%
**44
99%
IMR 4831
<<locked>>
81%
38812
61%
**80
99%
[IMR 4955 Enduron]*
<<locked>>
81%
35520
56%
**79
92%
[IMR 7828 SSC]*
<<locked>>
81%
34040
53%
**31
91%
Lovex S065
<<locked>>
81%
46833
73%
**89
100%
Lovex S070
<<locked>>
81%
45121
71%
**85
99%
[Lovex S071]*
<<locked>>
81%
28616
45%
**41
94%
Norma 204
<<locked>>
81%
43076
67%
**79
97%
[Norma 217]*
<<locked>>
91%
27253
43%
**00
90%
Norma MRP
<<locked>>
81%
34664
54%
**80
96%
Norma URP
<<locked>>
81%
44121
69%
**95
100%
Ramshot Hunter
<<locked>>
81%
42888
67%
**95
99%
[Ramshot Magnum]*
<<locked>>
81%
30530
48%
**43
93%
ReloadSwiss RS 14
<<locked>>
87%
31691
50%
**47
100%
ReloadSwiss RS 60
<<locked>>
81%
47674
75%
**30
100%
ReloadSwiss RS 62
<<locked>>
81%
44599
70%
**35
100%
ReloadSwiss RS 70
<<locked>>
81%
42989
67%
**44
100%
[ReloadSwiss RS 76]*
<<locked>>
82%
27369
43%
**93
90%
[ReloadSwiss RS 80]*
<<locked>>
93%
34998
55%
**07
90%
Rottweil R 903
<<locked>>
81%
52054
82%
**74
100%
[Rottweil R 904]*
<<locked>>
81%
38986
61%
**64
94%
Rottweil R 905
<<locked>>
81%
36767
58%
**64
95%
Rottweil R 907
<<locked>>
81%
48095
75%
**12
99%
SNPE Vectan SP 11
<<locked>>
81%
53417
84%
**26
100%
SNPE Vectan Tubal 5000
<<locked>>
81%
52446
82%
**59
100%
SNPE Vectan Tubal 7000
<<locked>>
81%
45803
72%
**43
99%
Shooters World Long Rifle
<<locked>>
81%
46833
73%
**89
100%
Somchem S355
<<locked>>
81%
51909
81%
**67
100%
[Somchem S361]*
<<locked>>
81%
39595
62%
**57
93%
Somchem S365
<<locked>>
81%
40872
64%
**59
100%
Somchem S385
<<locked>>
81%
37231
58%
**44
96%
Vihtavuori N135
<<locked>>
81%
50531
79%
**62
100%
Vihtavuori N150
<<locked>>
81%
44788
70%
**23
100%
Vihtavuori N160
<<locked>>
81%
47369
74%
**25
100%
[Vihtavuori N165]*
<<locked>>
81%
31401
49%
**06
93%
Vihtavuori N550
<<locked>>
81%
48051
75%
**67
100%
Vihtavuori N555
<<locked>>
81%
35694
56%
**61
99%
[Vihtavuori N560]*
<<locked>>
81%
33330
52%
**21
90%
[Vihtavuori N565]*
<<locked>>
84%
31792
50%
**85
90%
[Vihtavuori N568]*
<<locked>>
92%
36056
56%
**16
90%
Winchester 6.5 StaBALL
<<locked>>
81%
44556
70%
**56
100%
Winchester 760
<<locked>>
81%
50662
79%
**26
99%
Winchester StaBALL HD
<<locked>>
81%
26760
42%
**88
99%

Start Load - Barrel Length: 23.60''

Any powder missing? Then click here.

FR ... fill rate of the cartridge in percent

MaxP ... max. pressure of load in psi or bar

% ... max. pressure of load in percent of the maximum allowed pressure for this caliber 

V(0) ... muzzle velocity in feet per second (fps) or  meters per second (m/s)

z ... powder burnt in percent

[...] *... not dangerous but load has suboptimal powder burnt with possible characteristics such as extensive muzzle flash or inaccurate loads.

[...] ²... fill rate low - you might want to consider using a filler to ensure proper ignition.

[...] ᴾ... possible press load - work up slowly to this load while watching for signs of excessive pressure.

👍  ... recommended powder/load for this caliber and bullet combination based on its ballistic performance.

<<locked>>... you need to buy an access license to unlock the data

bottom of page