QL 28 Nosler Retumbo 180 Hybrid Pressures??

[MAinAR]

QL Request with known data, wondering just what pressures actually are predicted.

28 Nosler
180 Berger Hybrid seated .010 off
Fired case H2O 102.1 grains
OAL 3.707
Average Velocity at 3,137 (magento speed)
81 grains Retumbo
Temp was at 70 degrees.
24" Barrel

This should be interesting.

 

[FOTIS]

No 28 Nosler yet on Q/L. However based on this

Just as the 7mm STW is a necked-up version of the 6.5 STW, so it goes with the .28 Nosler and the .26 Nosler. When filled to the brim, the .28 Nosler case holds 100.7 grains of water versus 99.6 grains for 7mm STW cases made by Remington and 100.2 grains for those from Federal. Those are insignificant differences in cases of such large capacities.

Read more: http://www.shootingtimes.com/ammo/28-no ... z3mfJrueNj

Cartridge          : 7 mm STW
Bullet             : .284, 180, Berger Hybrid G7 #28407
Useable Case Capaci: 86.806 grain H2O = 5.636 cm³
Cartridge O.A.L. L6: 3.707 inch = 94.16 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : Hodgdon Retumbo

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   81    64.80   2355    2217   31496  12573     98.0    1.733
-18.0   83    66.42   2416    2332   33728  12879     98.8    1.690
-16.0   85    68.04   2476    2450   36122  13149     99.4    1.648
-14.0   87    69.66   2536    2570   38693  13380     99.8    1.596
-12.0   89    71.28   2595    2691   41454  13570    100.0    1.545
-10.0   91    72.90   2653    2814   44424  13724    100.0    1.495
-08.0   93    74.52   2711    2937   47618  13872    100.0    1.448
-06.0   95    76.14   2768    3062   51056  14015    100.0    1.402
-04.0   97    77.76   2824    3187   54758  14154    100.0    1.358
-02.0   99    79.38   2880    3314   58737  14289    100.0    1.315  ! Near Maximum !
+00.0  101    81.00   2935    3442   62975  14420    100.0    1.275  ! Near Maximum !
+02.0  103    82.62   2989    3571   67509  14546    100.0    1.235  !DANGEROUS LOAD-DO NOT USE!
+04.0  105    84.24   3043    3702   72365  14668    100.0    1.198  !DANGEROUS LOAD-DO NOT USE!
+06.0  107    85.86   3097    3834   77569  14784    100.0    1.162  !DANGEROUS LOAD-DO NOT USE!
+08.0  109    87.48   3151    3968   83153  14896    100.0    1.127  !DANGEROUS LOAD-DO NOT USE!
+10.0  111    89.10   3204    4103   89151  15002    100.0    1.093  !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    101    81.00   3042    3698   77430  13950    100.0    1.173  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba    101    81.00   2770    3066   49343  15082     99.9    1.412

 

[desertcj]

Looks like 83,000psi?! Or am I reading it wrong?

 

[MAinAR]

Looks like 83,000psi?! Or am I reading it wrong?

Yep looks like it, but

No sticky bolt
No stretch primer pockets
Primer not completely flat to edge
Fired brass chambers right back smooth

Plus Nosler data with 175gr PT/LRAB is max load at 83gr Retumbo at 3,228fps in 26" test barrel

?????

 

[FOTIS]

Correct but not a panacea just a prediction......

I know my 7mm STW with a barrel sendero did 3205 fps with a 160 AccuBond. So adding 20 more grains bullet ........... 2" less barrel......... and only 100 fps less Yes you should be up there....

 

[Wyo7200]

If you adjust the weighting factor to be more "overbore" to match the 7mm rather than going with the .6 value QL lists, you get a lot less pressure, closer matched velocities for the chronographed charges, without having to increase the BR as much. Using Fotis's info, with weighting factor of .4 :

Cartridge          : 7 mm STW
Bullet             : .284, 180, Berger Hybrid G7 #28407
Useable Case Capaci: 86.816 grain H2O = 5.637 cm³
Cartridge O.A.L. L6: 3.707 inch = 94.16 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : Hodgdon Retumbo

Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.0% 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

-10.0   93    74.70   2755    3034   44373  15102    100.0    1.442
-09.0   94    75.53   2787    3104   45927  15196    100.0    1.418
-08.0   95    76.36   2818    3175   47537  15284    100.0    1.395
-07.0   96    77.19   2850    3246   49210  15370    100.0    1.372
-06.0   97    78.02   2881    3317   50947  15456    100.0    1.350
-05.0   98    78.85   2912    3389   52748  15540    100.0    1.328
-04.0   99    79.68   2943    3461   54620  15624    100.0    1.306
-03.0  100    80.51   2973    3534   56564  15706    100.0    1.285
-02.0  101    81.34   3004    3607   58581  15787    100.0    1.264  ! Near Maximum !
-01.0  102    82.17   3034    3680   60679  15866    100.0    1.244  ! Near Maximum !
+00.0  103    83.00   3065    3754   62857  15945    100.0    1.224  ! Near Maximum !
+01.0  104    83.83   3095    3829   65123  16022    100.0    1.204  ! Near Maximum !
+02.0  105    84.66   3125    3904   67468  16097    100.0    1.185  !DANGEROUS LOAD-DO NOT USE!
+03.0  106    85.49   3155    3980   69893  16172    100.0    1.166  !DANGEROUS LOAD-DO NOT USE!
+04.0  107    86.32   3185    4056   72406  16245    100.0    1.148  !DANGEROUS LOAD-DO NOT USE!
+05.0  108    87.15   3215    4132   75012  16316    100.0    1.129  !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    103    83.00   3131    3918   70372  15644    100.0    1.170  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 5% relative to nominal value:
-Ba    103    83.00   2983    3556   55738  16309    100.0    1.286

I went over this in the QL questions thread. I think QL has the weighing values wrong for many of these calibers that are considered more overbore. If you enter the measurements into the caliber creator- QL estimates them closer to the overbore value of .33. This also reflects the Nosler load data of 83 gr max being close to saami max pressures- at least for the STW.

.33:

Cartridge          : 7 mm STW
Bullet             : .284, 180, Berger Hybrid G7 #28407
Useable Case Capaci: 86.816 grain H2O = 5.637 cm³
Cartridge O.A.L. L6: 3.707 inch = 94.16 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : Hodgdon Retumbo

Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.0% 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

-10.0   91    72.90   2696    2906   40088  15260     99.5    1.495
-09.0   92    73.71   2728    2975   41433  15397     99.7    1.471
-08.0   93    74.52   2760    3045   42825  15524     99.8    1.447
-07.0   94    75.33   2792    3115   44269  15640     99.9    1.424
-06.0   95    76.14   2824    3186   45762  15746    100.0    1.401
-05.0   96    76.95   2855    3258   47311  15841    100.0    1.379
-04.0   97    77.76   2887    3330   48915  15931    100.0    1.356
-03.0   98    78.57   2918    3403   50578  16020    100.0    1.335
-02.0   99    79.38   2949    3476   52301  16108    100.0    1.313
-01.0  100    80.19   2980    3549   54089  16195    100.0    1.293
+00.0  101    81.00   3011    3623   55943  16281    100.0    1.272
+01.0  102    81.81   3042    3697   57867  16365    100.0    1.252  ! Near Maximum !
+02.0  103    82.62   3072    3772   59863  16448    100.0    1.232  ! Near Maximum !
+03.0  104    83.43   3103    3848   61936  16530    100.0    1.213  ! Near Maximum !
+04.0  105    84.24   3133    3924   64089  16611    100.0    1.194  ! Near Maximum !
+05.0  106    85.05   3164    4000   66324  16690    100.0    1.175  !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    81.00   3084    3801   62743  15955    100.0    1.214  ! Near Maximum !
Data for burning rate decreased by 5% relative to nominal value:
-Ba    101    81.00   2920    3407   49752  16657     99.9    1.338

If you measure a couple of your 28 cases, I can build a profile for you in QL. No need to wait for the next update...

 

[MAinAR]

Nosler tech tells me the 28 saami drawing to be released is "exactly" same dimensions as 26 Nosler with approx .281 neck on factory brass. If you click image you can hit + to zoom up and get any dimension.

 

[Wyo7200]

Nevermind- stole it from the 26 nosler. give me a sec to work out the details-

 

[MAinAR]

Nevermind- stole it from the 26 nosler. give me a sec to work out the details-

Thank You!!

 

[Wyo7200]

Interesting stuff. The caliber creator estimated the weighting factor to be .4 for the dimensions of the case. Weighting factor set to .33, BR stock.

Cartridge          : .28 Nosler
Bullet             : .284, 180, Berger Hybrid G7 #28407
Useable Case Capaci: 95.975 grain H2O = 6.232 cm³
Cartridge O.A.L. L6: 3.707 inch = 94.16 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : Hodgdon Retumbo

Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.0% 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

-10.0   82    72.90   2558    2615   34017  15190     98.3    1.635
-09.0   83    73.71   2588    2676   35068  15365     98.7    1.616
-08.0   84    74.52   2617    2738   36153  15532     99.0    1.598
-07.0   85    75.33   2647    2801   37272  15691     99.2    1.576
-06.0   86    76.14   2677    2864   38426  15842     99.5    1.553
-05.0   86    76.95   2707    2928   39618  15984     99.6    1.529
-04.0   87    77.76   2736    2993   40849  16117     99.8    1.506
-03.0   88    78.57   2766    3057   42118  16241     99.9    1.484
-02.0   89    79.38   2795    3123   43428  16355    100.0    1.461
-01.0   90    80.19   2824    3189   44781  16460    100.0    1.440
+00.0   91    81.00   2854    3255   46179  16558    100.0    1.419
+01.0   92    81.81   2883    3321   47621  16655    100.0    1.398
+02.0   93    82.62   2912    3388   49112  16751    100.0    1.377
+03.0   94    83.43   2940    3455   50651  16846    100.0    1.357
+04.0   95    84.24   2969    3523   52242  16940    100.0    1.337
+05.0   96    85.05   2997    3591   53886  17033    100.0    1.317

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     91    81.00   2932    3435   51669  16236    100.0    1.352
Data for burning rate decreased by 5% relative to nominal value:
-Ba     91    81.00   2758    3039   41153  16751     99.1    1.494

adjusting the BR to match velocity-

Cartridge          : .28 Nosler
Bullet             : .284, 180, Berger Hybrid G7 #28407
Useable Case Capaci: 95.975 grain H2O = 6.232 cm³
Cartridge O.A.L. L6: 3.707 inch = 94.16 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : Hodgdon Retumbo ?

Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.0% 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

-10.0   82    72.90   2890    3338   56164  14252    100.0    1.321
-09.0   83    73.71   2916    3398   57871  14363    100.0    1.302  ! Near Maximum !
-08.0   84    74.52   2941    3457   59622  14473    100.0    1.284  ! Near Maximum !
-07.0   85    75.33   2966    3517   61419  14582    100.0    1.266  ! Near Maximum !
-06.0   86    76.14   2992    3577   63262  14690    100.0    1.248  ! Near Maximum !
-05.0   86    76.95   3017    3638   65153  14797    100.0    1.231  ! Near Maximum !
-04.0   87    77.76   3042    3699   67093  14904    100.0    1.214  !DANGEROUS LOAD-DO NOT USE!
-03.0   88    78.57   3067    3760   69084  15010    100.0    1.198  !DANGEROUS LOAD-DO NOT USE!
-02.0   89    79.38   3092    3821   71128  15115    100.0    1.182  !DANGEROUS LOAD-DO NOT USE!
-01.0   90    80.19   3117    3883   73225  15219    100.0    1.166  !DANGEROUS LOAD-DO NOT USE!
+00.0   91    81.00   3142    3946   75377  15322    100.0    1.150  !DANGEROUS LOAD-DO NOT USE!
+01.0   92    81.81   3167    4008   77586  15424    100.0    1.135  !DANGEROUS LOAD-DO NOT USE!
+02.0   93    82.62   3192    4071   79854  15525    100.0    1.120  !DANGEROUS LOAD-DO NOT USE!
+03.0   94    83.43   3216    4135   82183  15625    100.0    1.105  !DANGEROUS LOAD-DO NOT USE!
+04.0   95    84.24   3241    4199   84575  15725    100.0    1.091  !DANGEROUS LOAD-DO NOT USE!
+05.0   96    85.05   3266    4263   87031  15823    100.0    1.077  !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     91    81.00   3180    4042   81900  15150    100.0    1.110  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 5% relative to nominal value:
-Ba     91    81.00   3096    3831   68651  15527    100.0    1.197  !DANGEROUS LOAD-DO NOT USE!

I wonder if the actual case weight will change anything. I had to guess on that and override the H2o capacity. The creator wanted a case that weighed ~300gr for its est. 100gr H2O capacity.

Cartridge          : .28 Nosler
Bullet             : .284, 180, Berger Hybrid G7 #28407
Useable Case Capaci: 92.790 grain H2O = 6.025 cm³
Cartridge O.A.L. L6: 3.707 inch = 94.16 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : Hodgdon Retumbo ?

Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.0% 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

-10.0   85    72.90   2862    3274   52218  14482    100.0    1.355
-09.0   86    73.71   2889    3336   53882  14588    100.0    1.335
-08.0   87    74.52   2916    3399   55593  14695    100.0    1.315
-07.0   88    75.33   2943    3462   57352  14800    100.0    1.296  ! Near Maximum !
-06.0   89    76.14   2970    3525   59160  14904    100.0    1.277  ! Near Maximum !
-05.0   89    76.95   2996    3588   61019  15008    100.0    1.258  ! Near Maximum !
-04.0   90    77.76   3023    3652   62931  15110    100.0    1.240  ! Near Maximum !
-03.0   91    78.57   3049    3716   64896  15212    100.0    1.222  ! Near Maximum !
-02.0   92    79.38   3075    3780   66918  15312    100.0    1.205  !DANGEROUS LOAD-DO NOT USE!
-01.0   93    80.19   3102    3845   68997  15412    100.0    1.188  !DANGEROUS LOAD-DO NOT USE!
+00.0   94    81.00   3128    3911   71136  15511    100.0    1.171  !DANGEROUS LOAD-DO NOT USE!
+01.0   95    81.81   3154    3976   73336  15608    100.0    1.155  !DANGEROUS LOAD-DO NOT USE!
+02.0   96    82.62   3180    4043   75599  15705    100.0    1.139  !DANGEROUS LOAD-DO NOT USE!
+03.0   97    83.43   3206    4109   77929  15801    100.0    1.123  !DANGEROUS LOAD-DO NOT USE!
+04.0   98    84.24   3232    4176   80326  15895    100.0    1.108  !DANGEROUS LOAD-DO NOT USE!
+05.0   99    85.05   3258    4244   82794  15989    100.0    1.092  !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     94    81.00   3173    4024   77960  15306    100.0    1.127  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 5% relative to nominal value:
-Ba     94    81.00   3073    3775   64181  15755    100.0    1.223  ! Near Maximum !

Time to get a pressure trace.

 

[Woodycreek]

Watching this thread with great interest. Just ordered dies and brass for the 28 Nosler today.

 

[DrMike]

And we'll be watching for your posts, Brian. Pretty exciting cartridge. I hope to have opportunity to do some load development on this cartridge soon.

 

[Wyo7200]

-will update soon.

 

[MAinAR]

Is that OAL 3.707 correct? Probably is, but just checking since the Saami lists 3.340 as max. Bergers are special, I know.

Yes, exactly correct, using in Wyatts extended magazine. Can load up to i think 3.81 and still fit mag well.

.010 off lands at this OAL, shoots good here, 300yd average 3 shots groups hanging around 1.5 - 1.75"

 

[Wyo7200]

I'm stuck. I think the rests lies with the BR/ progressive/ degressive characteristics of Retumbo. Here is the cartridge info for those that have QL. Copy and paste into the qloadfw file.

".28 Nosler Update                       ","102.1","2.59",".2839",".40","40.476","448.16","Piezo SAAMI","3.34","2.166","2.331",".035",".534",".55",".528",".297",".284","0","300.0",".284¦.095¦.28¦.0527¦6¦0",""

I adjusted a lot of the Retumbo characteristic numbers to get the velocity to match your chrono and pressure signs as well as the published load data max of 83gr. This is of course, hypothetical.

Cartridge          : .28 Nosler Update
Bullet             : .284, 180, Berger Hybr G7 #28407
Useable Case Capaci: 96.075 grain H2O = 6.238 cm³
Cartridge O.A.L. L6: 3.707 inch = 94.16 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : Hodgdon Retumbo ?

Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.0% 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

-10.0   82    72.90   2865    3282   44492  15894    100.0    1.447
-09.0   83    73.71   2893    3346   45935  16009    100.0    1.426
-08.0   84    74.52   2921    3410   47428  16123    100.0    1.404
-07.0   85    75.33   2949    3475   48970  16236    100.0    1.383
-06.0   86    76.14   2976    3541   50563  16349    100.0    1.362
-05.0   86    76.95   3004    3607   52210  16460    100.0    1.342
-04.0   87    77.76   3031    3673   53912  16570    100.0    1.322
-03.0   88    78.57   3059    3739   55673  16679    100.0    1.302  ! Near Maximum !
-02.0   89    79.38   3086    3806   57492  16787    100.0    1.283  ! Near Maximum !
-01.0   90    80.19   3113    3874   59374  16894    100.0    1.264  ! Near Maximum !
+00.0   91    81.00   3140    3941   61316  17000    100.0    1.246  ! Near Maximum !
+01.0   92    81.81   3167    4010   63331  17105    100.0    1.228  ! Near Maximum !
+02.0   93    82.62   3194    4078   65414  17209    100.0    1.210  !DANGEROUS LOAD-DO NOT USE!
+03.0   94    83.43   3221    4147   67568  17312    100.0    1.192  !DANGEROUS LOAD-DO NOT USE!
+04.0   95    84.24   3248    4217   69793  17413    100.0    1.175  !DANGEROUS LOAD-DO NOT USE!
+05.0   96    85.05   3275    4287   72103  17513    100.0    1.158  !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     91    81.00   3197    4084   69585  16727    100.0    1.188  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 5% relative to nominal value:
-Ba     91    81.00   3071    3769   54030  17328    100.0    1.311

 

[muleman]

I did something similar to project data for my 28Nosler. I'm running mine with 175ABLRs and 195 Bergers. My mag box is 3.65 so I'm running the Bergers at 3.61 and the ABLRs to match the throat. I created a new case using 26Nosler data and actual capacity of my necked 26Nosler brass(100.0gr) My capacity is different because the necks are a wee bit shorter than the 28Nosler cases. I'm running a 26"barrel and QL projects 3150fps plus with RL33 and 175ABLRs and 3050 plus for the 195s.
Scott