USE THIS DATA AT YOUR OWN RISK.
Code
Cartridge          : 7.21 Firebird (Lazzeroni)
Bullet             : .284, 160, Nosler AccuBond 54932
Useable Case Capaci: 102.463 grain H2O = 6.653 cm³
Cartridge O.A.L. L6: 3.600 inch = 91.44 mm
Barrel Length      : 28.0 inch = 711.2 mm
Powder             : Norma 217

Predicted data by increasing and decreasing the given charge,
incremented in steps of 0.213% 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   99    91.80   3258    3771   61074  13637    100.0    1.385  ! Near Maximum !
-01.9   99    92.00   3265    3786   61521  13649    100.0    1.380  ! Near Maximum !
-01.7   99    92.20   3271    3801   61971  13661    100.0    1.376  ! Near Maximum !
-01.5   99    92.40   3277    3816   62425  13673    100.0    1.371  ! Near Maximum !
-01.3  100    92.60   3284    3831   62881  13685    100.0    1.367  ! Near Maximum !
-01.1  100    92.80   3290    3846   63341  13697    100.0    1.362  ! Near Maximum !
-00.9  100    93.00   3297    3861   63804  13709    100.0    1.358  ! Near Maximum !
-00.6  100    93.20   3303    3877   64271  13721    100.0    1.353  ! Near Maximum !
-00.4  100    93.40   3310    3892   64740  13733    100.0    1.349  ! Near Maximum !
-00.2  101    93.60   3316    3907   65213  13745    100.0    1.344  ! Near Maximum !
+00.0  101    93.80   3322    3922   65689  13757    100.0    1.340  ! Near Maximum !
+00.2  101    94.00   3329    3937   66169  13768    100.0    1.335  !DANGEROUS LOAD-DO NOT USE!
+00.4  101    94.20   3335    3952   66652  13780    100.0    1.331  !DANGEROUS LOAD-DO NOT USE!
+00.6  101    94.40   3342    3967   67138  13792    100.0    1.326  !DANGEROUS LOAD-DO NOT USE!
+00.9  102    94.60   3348    3982   67628  13803    100.0    1.322  !DANGEROUS LOAD-DO NOT USE!
+01.1  102    94.80   3354    3997   68121  13815    100.0    1.318  !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 5% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 5% relative to nominal value:
+Ba    101    93.80   3387    4077   72976  13505    100.0    1.280  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 5% relative to nominal value:
-Ba    101    93.80   3242    3734   58399  14061    100.0    1.410  ! Near Maximum !


Code
Cartridge          : 7.21 Firebird (Lazzeroni)
Bullet             : .284, 160, Nosler AccuBond 54932
Useable Case Capaci: 102.463 grain H2O = 6.653 cm³
Cartridge O.A.L. L6: 3.600 inch = 91.44 mm
Barrel Length      : 28.0 inch = 711.2 mm
Powder             : Vihtavuori N570

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   93    93.10   3323    3924   61029  15446     99.7    1.365  ! Near Maximum !
-01.9   94    93.30   3331    3941   61471  15464     99.7    1.360  ! Near Maximum !
-01.7   94    93.50   3338    3958   61916  15481     99.8    1.356  ! Near Maximum !
-01.5   94    93.70   3345    3975   62364  15499     99.8    1.351  ! Near Maximum !
-01.3   94    93.90   3352    3993   62815  15516     99.8    1.347  ! Near Maximum !
-01.1   94    94.10   3360    4010   63269  15532     99.8    1.342  ! Near Maximum !
-00.8   95    94.30   3367    4028   63726  15548     99.9    1.338  ! Near Maximum !
-00.6   95    94.50   3374    4045   64187  15564     99.9    1.333  ! Near Maximum !
-00.4   95    94.70   3381    4062   64651  15579     99.9    1.329  ! Near Maximum !
-00.2   95    94.90   3389    4080   65118  15594     99.9    1.324  ! Near Maximum !
+00.0   95    95.10   3396    4097   65589  15608     99.9    1.320  ! Near Maximum !
+00.2   96    95.30   3403    4115   66063  15622     99.9    1.316  !DANGEROUS LOAD-DO NOT USE!
+00.4   96    95.50   3410    4132   66541  15636    100.0    1.311  !DANGEROUS LOAD-DO NOT USE!
+00.6   96    95.70   3418    4150   67021  15649    100.0    1.307  !DANGEROUS LOAD-DO NOT USE!
+00.8   96    95.90   3425    4167   67506  15662    100.0    1.303  !DANGEROUS LOAD-DO NOT USE!
+01.1   96    96.10   3432    4185   67993  15674    100.0    1.298  !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 5% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 5% relative to nominal value:
+Ba     95    95.10   3481    4305   72707  15279    100.0    1.261  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 5% relative to nominal value:
-Ba     95    95.10   3292    3850   58541  15743     98.7    1.388  ! Near Maximum !

“There are three things all wise men fear: the sea in storm, a night with no moon, and the anger of a gentle man.”
― Patrick Rothfuss, The Wise Man's Fear