Replacement for Vihtavuori N560

Dr. Vette

Dr. Vette

Handloader
Apr 16, 2012
1,480
366
My business/hunting partner purchased two used McWhorter rifles recently. One is a 257 Weatherby, the other a 6.5 Weatherby based on the 257. Both of the loads that McWhorter made use the Vihtavuori N560 powder, which is impossible to find.

Any recommendations for a similar substitute powder?

Thanks.
 
If I run QL with 110 grain AB and N560 in the 257 WBY, I get this profile:

Code: 
Cartridge          : .257 Weath. Mag
Bullet             : .257, 110, Nosler AccuBond 53742
Useable Case Capaci: 76.606 grain H2O = 4.974 cm³
Cartridge O.A.L. L6: 3.170 inch = 80.52 mm
Barrel Length      : 26.0 inch = 660.4 mm
Powder             : Vihtavuori N560

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% 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

-20.0   75    54.40   2786    1895   32578  11756     90.6    1.579
-18.0   77    55.76   2856    1992   34825  12136     92.0    1.541
-16.0   79    57.12   2926    2091   37229  12502     93.2    1.501
-14.0   81    58.48   2996    2193   39769  12852     94.4    1.454
-12.0   83    59.84   3066    2296   42447  13185     95.5    1.410
-10.0   85    61.20   3136    2402   45289  13500     96.4    1.367
-08.0   87    62.56   3206    2510   48309  13793     97.3    1.326
-06.0   89    63.92   3275    2620   51519  14065     98.0    1.287
-04.0   90    65.28   3344    2732   54931  14313     98.6    1.249  ! Near Maximum !
-02.0   92    66.64   3413    2845   58559  14536     99.1    1.212  ! Near Maximum !
+00.0   94    68.00   3481    2960   62417  14732     99.5    1.177  ! Near Maximum !
+02.0   96    69.36   3548    3076   66522  14901     99.8    1.143  !DANGEROUS LOAD-DO NOT USE!
+04.0   98    70.72   3615    3193   70892  15042    100.0    1.111  !DANGEROUS LOAD-DO NOT USE!
+06.0  100    72.08   3682    3311   75547  15153    100.0    1.079  !DANGEROUS LOAD-DO NOT USE!
+08.0  102    73.44   3747    3429   80509  15251    100.0    1.049  !DANGEROUS LOAD-DO NOT USE!
+10.0  104    74.80   3812    3549   85803  15346    100.0    1.019  !DANGEROUS LOAD-DO NOT USE!

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     94    68.00   3634    3226   74563  14268    100.0    1.087  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba     94    68.00   3264    2602   50425  14482     94.8    1.295

Running a propellant table, I get these powders.

Code: 
Cartridge          : .257 Weath. Mag
Bullet             : .257, 110, Nosler AccuBond 53742
Useable Case Capaci: 76.606 grain H2O = 4.974 cm³
Cartridge O.A.L. L6: 3.170 inch = 80.52 mm
Barrel Length      : 26.0 inch = 660.4 mm

Predicted Data for Indicated Charges of the Following Powders.
Matching Maximum Pressure: 63000 psi, or 434 MPa
or a maximum loading ratio or filling of 110 %
These calculations refer to your specified settings in QuickLOAD 'Cartridge Dimensions' window.
C A U T I O N : any load listed can result in a powder charge that falls below minimum suggested
loads or exceeds maximum suggested loads as presented in current handloading manuals. Understand
that all of the listed powders can be unsuitable for the given combination of cartridge, bullet
and gun. Actual load order can vary, depending upon lot-to-lot powder and component variations.
USE ONLY FOR COMPARISON !

42 loads produced a Loading Ratio below user-defined minimum of 90%. These powders have been skipped.
Powder type          Filling/Loading Ratio  Charge    Charge   Vel. Prop.Burnt P max  P muzz  B_Time
                                      %     Grains    Gramm   fps     %       psi     psi    ms
---------------------------------  -----------------------------------------------------------------
ADI AR 2218                        106.9     80.4     5.21    3583    98.3    63000   16646   1.153  ! Near Maximum !
Vihtavuori N570                    102.8     76.5     4.96    3551    97.8    63000   16281   1.179  ! Near Maximum !
Alliant Reloder-33                 102.4     79.5     5.15    3529    98.4    63000   15958   1.183  ! Near Maximum !
Hodgdon H870                       109.0     79.5     5.15    3521    99.1    63000   15665   1.184  ! Near Maximum !
Alliant Reloder-50                 109.0     83.2     5.39    3519    97.7    63000   16307   1.208  ! Near Maximum !
ADI AR 2225                        106.6     75.7     4.90    3516   100.0    63000   14296   1.170  ! Near Maximum !
Hodgdon Retumbo                    106.6     75.7     4.90    3516   100.0    63000   14296   1.170  ! Near Maximum !
Vihtavuori N560                     94.5     68.2     4.42    3491    99.6    63000   14758   1.172  ! Near Maximum !
Norma MRP 2                        102.1     72.1     4.67    3484    99.9    63000   14649   1.188  ! Near Maximum !
Bofors RP30                        102.1     72.1     4.67    3484    99.9    63000   14649   1.188  ! Near Maximum !
PB Clermont PCL 517                 97.1     73.2     4.74    3482    99.9    63000   14402   1.174  ! Near Maximum !
IMR 7828 SSC                        93.5     67.8     4.39    3482    99.8    63000   14313   1.162  ! Near Maximum !
IMR 7828                            98.8     67.8     4.39    3482    99.8    63000   14313   1.162  ! Near Maximum !
SNPE Vectan SP 12                   97.0     73.1     4.74    3482   100.0    63000   14371   1.174  ! Near Maximum !
Accurate MAGPRO                     94.7     71.1     4.61    3480    98.9    63000   14900   1.182  ! Near Maximum !
Norma MRP                           92.6     68.3     4.42    3478   100.0    63000   14148   1.181  ! Near Maximum !
ADI AR 2213                         94.7     67.6     4.38    3471    99.7    63000   14205   1.158  ! Near Maximum !
ADI AP 2214                         98.4     72.2     4.68    3470    99.9    63000   13979   1.158  ! Near Maximum !
Alliant Reloder-25                  99.9     70.2     4.55    3469   100.0    63000   13597   1.176  ! Near Maximum !
Hodgdon H1000                      103.5     72.3     4.68    3467    99.9    63000   13939   1.158  ! Near Maximum !
ADI AR 2217                        103.5     72.3     4.68    3467    99.9    63000   13939   1.158  ! Near Maximum !
Alliant Reloder-22                  94.8     67.7     4.39    3459   100.0    63000   14073   1.177  ! Near Maximum !
Raufoss RA15                        94.8     67.7     4.39    3459   100.0    63000   14073   1.177  ! Near Maximum !
Bofors RP5/NP ~approximation        94.8     67.7     4.39    3459   100.0    63000   14073   1.177  ! Near Maximum !
Bofors RP15                         97.4     68.0     4.41    3458   100.0    63000   14096   1.178  ! Near Maximum !
Winchester WXR                      97.4     68.0     4.41    3458   100.0    63000   14096   1.178  ! Near Maximum !
Vihtavuori 24N41                   105.7     79.5     5.15    3441    93.0    63000   14866   1.166  ! Near Maximum !
Bofors RP5 NT ~approximation        98.3     70.8     4.59    3440    98.8    63000   14125   1.159  ! Near Maximum !
Bofors 12,7mmRA NC1214 Lot20115087 109.3     81.6     5.29    3438    90.8    63000   15641   1.216  ! Near Maximum !
Rottweil R905                       96.3     67.5     4.37    3437    99.6    63000   13925   1.174  ! Near Maximum !
ADI AR 2209                         91.9     64.6     4.18    3430   100.0    63000   13467   1.159  ! Near Maximum !
Ramshot Magnum                      94.6     72.7     4.71    3428   100.0    63000   13379   1.181  ! Near Maximum !
Alliant Reloder-19                  92.4     65.2     4.23    3425   100.0    63000   13508   1.167  ! Near Maximum !
Bofors RP14 ~approximation          93.1     65.7     4.26    3417   100.0    63000   13413   1.168  ! Near Maximum !
Hodgdon H4831 SC                    93.7     66.9     4.34    3407    99.4    63000   13493   1.164  ! Near Maximum !
Hodgdon H4831                       97.5     66.9     4.34    3407    99.4    63000   13493   1.164  ! Near Maximum !
Raufoss RA4                         90.7     64.1     4.15    3406    99.9    63000   13233   1.165  ! Near Maximum !
Bofors RP4 ~approximation           90.7     64.1     4.15    3406    99.9    63000   13233   1.165  ! Near Maximum !
Hodgdon US 869                     110.0     82.7     5.36    3394    92.6    61249   14744   1.196  ! Near Maximum !
Hodgdon 50BMG                      110.0     78.9     5.11    3389    88.4    60488   14934   1.197  ! Near Maximum !
Vihtavuori N170                    106.4     74.3     4.81    3389    96.6    63000   14006   1.189  ! Near Maximum !
Rottweil R904                       91.7     63.9     4.14    3383    99.7    63000   13026   1.163  ! Near Maximum !
Somchem S385                        92.5     66.0     4.28    3378   100.0    63000   12843   1.187  ! Near Maximum !
Winchester Supreme 780              91.3     68.0     4.41    3372   100.0    63000   12853   1.175  ! Near Maximum !
Hodgdon H4350                       90.5     62.5     4.05    3365   100.0    63000   12486   1.164  ! Near Maximum !
Vihtavuori N165                     97.4     68.0     4.41    3362   100.0    63000   12574   1.180  ! Near Maximum !
Vihtavuori N160                     97.9     66.3     4.29    3361    99.7    63000   12774   1.168  ! Near Maximum !
Lovex D100                         103.3     78.5     5.09    3360    93.6    63000   13757   1.181  ! Near Maximum !
IMR 4831                            92.0     62.2     4.03    3358   100.0    63000   12186   1.188  ! Near Maximum !
Accurate 3100                       95.1     67.2     4.35    3350   100.0    63000   12403   1.206  ! Near Maximum !
Lovex S071                         100.6     67.2     4.35    3350   100.0    63000   12403   1.206  ! Near Maximum !
Somchem S361                        90.8     68.3     4.43    3345    99.4    63000   12775   1.176  ! Near Maximum !
Hodgdon Hybrid 100V                 90.0     61.5     3.99    3327   100.0    63000   11542   1.181  ! Near Maximum !
Accurate 8700                      110.0     81.1     5.25    3317    95.9    55159   14324   1.246  ! Near Maximum !
SNPE Vectan SP 13                  110.0     79.4     5.14    3316    95.8    56566   14255   1.250  ! Near Maximum !
Vihtavuori 20N29                   110.0     83.6     5.42    3303    93.5    55114   14598   1.266  ! Near Maximum !

By this criterion, Retumbo and MRP2 bracket N560. IMR7828SSC is in the neighbourhood.
 
Thanks Mike.

I just bought 5 pounds of 7828ssc today, so...

I also told him to call McWhorter.
 
I did set the maximum chamber pressures very close to SAAMI maximum pressures. The charges recommended should be within less than a few tenths of a grain of powder to achieve maximum chamber pressure.
 
Current load is for 67.0gr of N560 in the 257, and your listed max is 68.2
So, what you list as max is probably very close.

MRP2 is gone, and Retumbo is at least possible to obtain. I saw a few bottles of it today, though I don't think any 5 pounders.

How does the loading data show for the 7828ssc in this cartridge with the 110AB? That is, by the way, the bullet he will use in that rifle.
 
Code: 
Cartridge          : .257 Weath. Mag
Bullet             : .257, 110, Nosler AccuBond 53742
Useable Case Capaci: 76.606 grain H2O = 4.974 cm³
Cartridge O.A.L. L6: 3.170 inch = 80.52 mm
Barrel Length      : 26.0 inch = 660.4 mm
Powder             : IMR 7828 SSC

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% 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

-20.0   75    54.24   2780    1888   32335  11541     91.3    1.567
-18.0   77    55.60   2851    1985   34556  11910     92.6    1.529
-16.0   79    56.95   2921    2085   36934  12264     93.9    1.491
-14.0   80    58.31   2992    2187   39476  12600     95.0    1.444
-12.0   82    59.66   3063    2292   42194  12917     96.1    1.398
-10.0   84    61.02   3134    2398   45103  13213     97.0    1.355
-08.0   86    62.38   3204    2507   48216  13485     97.8    1.314
-06.0   88    63.73   3274    2618   51552  13733     98.5    1.274
-04.0   90    65.09   3344    2731   55122  13954     99.0    1.235  ! Near Maximum !
-02.0   92    66.44   3413    2845   58911  14147     99.5    1.198  ! Near Maximum !
+00.0   93    67.80   3482    2961   62949  14312     99.8    1.162  ! Near Maximum !
+02.0   95    69.16   3550    3078   67262  14446    100.0    1.128  !DANGEROUS LOAD-DO NOT USE!
+04.0   97    70.51   3617    3196   71873  14549    100.0    1.095  !DANGEROUS LOAD-DO NOT USE!
+06.0   99    71.87   3684    3314   76805  14637    100.0    1.063  !DANGEROUS LOAD-DO NOT USE!
+08.0  101    73.22   3750    3434   82087  14722    100.0    1.032  !DANGEROUS LOAD-DO NOT USE!
+10.0  103    74.58   3815    3555   87749  14802    100.0    1.002  !DANGEROUS LOAD-DO NOT USE!

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     93    67.80   3630    3219   75592  13794    100.0    1.074  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba     93    67.80   3267    2607   50731  14186     95.5    1.278
 
Mike - would a 24 inch barrel change anything?
I can't recall which of the 2 rifles has a 24 inch barrel.

Thanks for the QL info.

Patrick
 
You will lose a bit of velocity; chamber pressure will remain the same.

Code: 
Cartridge          : .257 Weath. Mag
Bullet             : .257, 110, Nosler AccuBond 53742
Useable Case Capaci: 76.606 grain H2O = 4.974 cm³
Cartridge O.A.L. L6: 3.170 inch = 80.52 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : IMR 7828 SSC

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% 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

-20.0   75    54.24   2705    1787   32334  12438     89.9    1.506
-18.0   77    55.60   2775    1881   34556  12858     91.4    1.469
-16.0   79    56.95   2845    1977   36934  13264     92.7    1.434
-14.0   80    58.31   2915    2076   39476  13653     94.0    1.387
-12.0   82    59.66   2986    2178   42194  14022     95.1    1.343
-10.0   84    61.02   3056    2282   45103  14369     96.1    1.301
-08.0   86    62.38   3127    2388   48216  14693     97.1    1.261
-06.0   88    63.73   3197    2496   51552  14992     97.9    1.222
-04.0   90    65.09   3267    2607   55122  15263     98.5    1.185  ! Near Maximum !
-02.0   92    66.44   3336    2719   58911  15505     99.1    1.149  ! Near Maximum !
+00.0   93    67.80   3406    2833   62949  15716     99.5    1.114  ! Near Maximum !
+02.0   95    69.16   3474    2948   67262  15895     99.8    1.081  !DANGEROUS LOAD-DO NOT USE!
+04.0   97    70.51   3542    3065   71872  16039    100.0    1.048  !DANGEROUS LOAD-DO NOT USE!
+06.0   99    71.87   3610    3183   76805  16150    100.0    1.017  !DANGEROUS LOAD-DO NOT USE!
+08.0  101    73.22   3677    3302   82087  16247    100.0    0.987  !DANGEROUS LOAD-DO NOT USE!
+10.0  103    74.58   3743    3422   87748  16340    100.0    0.958  !DANGEROUS LOAD-DO NOT USE!

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     93    67.80   3560    3095   75591  15208    100.0    1.028  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba     93    67.80   3188    2482   50731  15414     94.5    1.227

Code: 
Cartridge          : .257 Weath. Mag
Bullet             : .257, 110, Nosler AccuBond 53742
Useable Case Capaci: 76.606 grain H2O = 4.974 cm³
Cartridge O.A.L. L6: 3.170 inch = 80.52 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : Vihtavuori N560

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% 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

-20.0   75    54.40   2709    1793   32578  12658     89.3    1.518
-18.0   77    55.76   2779    1886   34825  13088     90.7    1.482
-16.0   79    57.12   2848    1982   37229  13505     92.1    1.444
-14.0   81    58.48   2918    2080   39769  13907     93.3    1.398
-12.0   83    59.84   2988    2180   42447  14292     94.5    1.355
-10.0   85    61.20   3057    2283   45289  14658     95.5    1.314
-08.0   87    62.56   3127    2388   48309  15003     96.5    1.274
-06.0   89    63.92   3196    2495   51519  15326     97.3    1.235
-04.0   90    65.28   3265    2605   54931  15624     98.0    1.199  ! Near Maximum !
-02.0   92    66.64   3334    2716   58559  15896     98.7    1.163  ! Near Maximum !
+00.0   94    68.00   3403    2828   62417  16141     99.2    1.129  ! Near Maximum !
+02.0   96    69.36   3471    2942   66522  16356     99.5    1.096  !DANGEROUS LOAD-DO NOT USE!
+04.0   98    70.72   3538    3058   70892  16541     99.8    1.064  !DANGEROUS LOAD-DO NOT USE!
+06.0  100    72.08   3605    3175   75547  16694    100.0    1.033  !DANGEROUS LOAD-DO NOT USE!
+08.0  102    73.44   3672    3293   80509  16815    100.0    1.004  !DANGEROUS LOAD-DO NOT USE!
+10.0  104    74.80   3737    3411   85803  16923    100.0    0.975  !DANGEROUS LOAD-DO NOT USE!

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     94    68.00   3562    3098   74562  15715    100.0    1.041  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba     94    68.00   3183    2474   50425  15711     93.7    1.244
 
Good that you found some powder to work with. Glad to have been of help.
 
I use 7828SSC in my 26" Mark V 257 Roy w/110 AB. No Pressure and sub MOA. It seems in these times of scarcity, 7828 is easier to find. Good luck.
sbsmith
 
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