QL Help for Barnes MRX

[sithlord6512]

Hi there,

Can someone please do a QL run for a Barnes 180 grain MRX in a .300 WSM (the kind that lists a "near max" charges for a variety of powders)?

I've experimented with this bullet in the past, but gave up on them - too pricey. However, I've just recieved an early X-mas gift of 2 full boxes of 180 g Barnes MRXs (20x2 bullets). I Will post the results - I'm sure it will be appreciated as there seems to be a dearth of MRX data out there (almost certainly because of their price). I have these powders - Viht N550, Viht N560, IMR 4831, IMR 4350, H4350, and RL17 (i.e., with the exception of IMR 4350, powders not in the Barnes#4 manual).

Thanks, in advance.

 

[DrMike]

Cartridge : .300 WSM (CIP)
Bullet : .308, 180, Barnes 'MRX'BT 30888
Useable Case Capaci: 70.266 grain H2O = 4.562 cm³
Cartridge O.A.L. L6: 2.860 inch = 72.64 mm
Barrel Length : 24.0 inch = 609.6 mm
Powder : Alliant Reloder-17

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 74 50.00 2462 2422 34670 8710 97.6 1.471
-18.0 75 51.25 2516 2531 36846 8917 98.3 1.437
-16.0 77 52.50 2571 2641 39154 9110 98.8 1.403
-14.0 79 53.75 2625 2754 41601 9288 99.3 1.371
-12.0 81 55.00 2679 2868 44201 9451 99.6 1.339
-10.0 83 56.25 2732 2983 46959 9596 99.8 1.302
-08.0 85 57.50 2785 3099 49892 9725 100.0 1.266
-06.0 86 58.75 2837 3216 53006 9836 100.0 1.232
-04.0 88 60.00 2888 3335 56320 9941 100.0 1.199 ! Near Maximum !
-02.0 90 61.25 2940 3454 59844 10044 100.0 1.167 ! Near Maximum !
+00.0 92 62.50 2990 3574 63598 10144 100.0 1.136 ! Near Maximum !
+02.0 94 63.75 3040 3695 67596 10241 100.0 1.107 !DANGEROUS LOAD-DO NOT USE!
+04.0 96 65.00 3090 3817 71861 10335 100.0 1.078 !DANGEROUS LOAD-DO NOT USE!
+06.0 98 66.25 3140 3940 76400 10427 100.0 1.050 !DANGEROUS LOAD-DO NOT USE!
+08.0 99 67.50 3189 4064 81275 10515 100.0 1.024 !DANGEROUS LOAD-DO NOT USE!
+10.0 101 68.75 3238 4190 86452 10600 100.0 0.998 !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 92 62.50 3080 3791 75380 9810 100.0 1.065 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 92 62.50 2854 3255 52629 10504 99.2 1.231

Cartridge : .300 WSM (CIP)
Bullet : .308, 180, Barnes 'MRX'BT 30888
Useable Case Capaci: 70.266 grain H2O = 4.562 cm³
Cartridge O.A.L. L6: 2.860 inch = 72.64 mm
Barrel Length : 24.0 inch = 609.6 mm
Powder : Vihtavuori N550

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 77 50.80 2422 2345 34011 8743 96.0 1.516
-18.0 79 52.07 2478 2454 36165 8970 96.8 1.480
-16.0 81 53.34 2534 2565 38451 9186 97.5 1.446
-14.0 83 54.61 2589 2678 40878 9389 98.2 1.412
-12.0 84 55.88 2644 2793 43452 9580 98.7 1.381
-10.0 86 57.15 2698 2910 46183 9756 99.2 1.343
-08.0 88 58.42 2752 3028 49081 9918 99.5 1.305
-06.0 90 59.69 2806 3147 52157 10064 99.8 1.269
-04.0 92 60.96 2859 3268 55423 10194 99.9 1.234 ! Near Maximum !
-02.0 94 62.23 2912 3390 58892 10307 100.0 1.200 ! Near Maximum !
+00.0 96 63.50 2965 3513 62579 10408 100.0 1.167 ! Near Maximum !
+02.0 98 64.77 3016 3637 66498 10506 100.0 1.136 !DANGEROUS LOAD-DO NOT USE!
+04.0 100 66.04 3068 3761 70669 10601 100.0 1.106 !DANGEROUS LOAD-DO NOT USE!
+06.0 102 67.31 3119 3888 75109 10693 100.0 1.077 !DANGEROUS LOAD-DO NOT USE!
+08.0 104 68.58 3169 4015 79842 10782 100.0 1.048 !DANGEROUS LOAD-DO NOT USE!
+10.0 106 69.85 3220 4143 84891 10868 100.0 1.021 !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 96 63.50 3064 3753 73981 10047 100.0 1.089 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 96 63.50 2815 3167 51309 10617 98.0 1.272

Cartridge : .300 WSM (CIP)
Bullet : .308, 180, Barnes 'MRX'BT 30888
Useable Case Capaci: 70.266 grain H2O = 4.562 cm³
Cartridge O.A.L. L6: 2.860 inch = 72.64 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 86 56.80 2410 2322 31768 9298 86.0 1.535
-18.0 88 58.22 2474 2447 33952 9629 87.5 1.494
-16.0 90 59.64 2538 2575 36301 9952 88.9 1.453
-14.0 92 61.06 2603 2708 38824 10266 90.3 1.414
-12.0 94 62.48 2668 2845 41541 10569 91.6 1.375
-10.0 97 63.90 2733 2986 44466 10860 92.8 1.338
-08.0 99 65.32 2799 3131 47620 11136 93.9 1.295
-06.0 101 66.74 2865 3281 51025 11398 95.0 1.254
-04.0 103 68.16 2931 3434 54704 11642 95.9 1.214
-02.0 105 69.58 2997 3591 58686 11868 96.8 1.176 ! Near Maximum !
+00.0 107 71.00 3064 3752 63002 12074 97.6 1.139 ! Near Maximum !
+02.0 109 72.42 3130 3916 67689 12258 98.2 1.103 !DANGEROUS LOAD-DO NOT USE!
+04.0 112 73.84 3197 4084 72778 12420 98.8 1.068 !DANGEROUS LOAD-DO NOT USE!
+06.0 114 75.26 3263 4256 78337 12557 99.2 1.034 !DANGEROUS LOAD-DO NOT USE!
+08.0 116 76.68 3329 4431 84400 12668 99.6 1.002 !DANGEROUS LOAD-DO NOT USE!
+10.0 118 78.10 3396 4609 91001 12753 99.8 0.970 !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 107 71.00 3224 4154 77032 11869 100.0 1.049 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 107 71.00 2850 3245 50707 11570 90.4 1.254

Cartridge : .300 WSM (CIP)
Bullet : .308, 180, Barnes 'MRX'BT 30888
Useable Case Capaci: 70.266 grain H2O = 4.562 cm³
Cartridge O.A.L. L6: 2.860 inch = 72.64 mm
Barrel Length : 24.0 inch = 609.6 mm
Powder : Hodgdon H4350

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 51.20 2376 2256 34106 8216 92.1 1.505
-18.0 83 52.48 2431 2362 36266 8456 93.2 1.470
-16.0 85 53.76 2486 2470 38535 8688 94.1 1.435
-14.0 87 55.04 2541 2580 40929 8912 95.0 1.401
-12.0 89 56.32 2595 2692 43470 9126 95.8 1.369
-10.0 91 57.60 2650 2807 46168 9330 96.6 1.331
-08.0 93 58.88 2704 2923 49033 9524 97.3 1.295
-06.0 95 60.16 2759 3041 52076 9706 97.9 1.259
-04.0 97 61.44 2813 3162 55311 9876 98.4 1.225 ! Near Maximum !
-02.0 99 62.72 2866 3284 58750 10033 98.9 1.192 ! Near Maximum !
+00.0 101 64.00 2920 3408 62409 10177 99.3 1.160 ! Near Maximum !
+02.0 103 65.28 2973 3533 66304 10306 99.6 1.129 !DANGEROUS LOAD-DO NOT USE!
+04.0 105 66.56 3026 3660 70454 10420 99.8 1.099 !DANGEROUS LOAD-DO NOT USE!
+06.0 107 67.84 3079 3789 74881 10518 99.9 1.070 !DANGEROUS LOAD-DO NOT USE!
+08.0 109 69.12 3131 3919 79605 10600 100.0 1.042 !DANGEROUS LOAD-DO NOT USE!
+10.0 111 70.40 3183 4050 84655 10669 100.0 1.015 !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 64.00 3030 3670 72951 9869 100.0 1.085 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 101 64.00 2766 3059 52054 10047 94.9 1.256

Cartridge : .300 WSM (CIP)
Bullet : .308, 180, Barnes 'MRX'BT 30888
Useable Case Capaci: 70.266 grain H2O = 4.562 cm³
Cartridge O.A.L. L6: 2.860 inch = 72.64 mm
Barrel Length : 24.0 inch = 609.6 mm
Powder : IMR 4350

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 79 51.20 2382 2267 34335 8233 92.4 1.501
-18.0 81 52.48 2437 2373 36504 8471 93.4 1.466
-16.0 83 53.76 2491 2481 38783 8702 94.4 1.432
-14.0 85 55.04 2546 2591 41194 8924 95.2 1.398
-12.0 87 56.32 2601 2704 43752 9136 96.1 1.365
-10.0 89 57.60 2655 2818 46469 9338 96.8 1.327
-08.0 91 58.88 2710 2935 49353 9530 97.5 1.291
-06.0 93 60.16 2764 3053 52417 9710 98.0 1.255
-04.0 95 61.44 2818 3174 55673 9877 98.6 1.221 ! Near Maximum !
-02.0 97 62.72 2872 3296 59135 10031 99.0 1.188 ! Near Maximum !
+00.0 99 64.00 2925 3420 62818 10171 99.4 1.156 ! Near Maximum !
+02.0 101 65.28 2978 3545 66738 10297 99.6 1.125 !DANGEROUS LOAD-DO NOT USE!
+04.0 103 66.56 3031 3672 70916 10408 99.8 1.096 !DANGEROUS LOAD-DO NOT USE!
+06.0 105 67.84 3084 3800 75370 10503 100.0 1.067 !DANGEROUS LOAD-DO NOT USE!
+08.0 107 69.12 3136 3930 80125 10582 100.0 1.039 !DANGEROUS LOAD-DO NOT USE!
+10.0 109 70.40 3188 4061 85206 10651 100.0 1.012 !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 99 64.00 3034 3679 73404 9854 100.0 1.083 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 99 64.00 2773 3072 52416 10060 95.1 1.252

Cartridge : .300 WSM (CIP)
Bullet : .308, 180, Barnes 'MRX'BT 30888
Useable Case Capaci: 70.266 grain H2O = 4.562 cm³
Cartridge O.A.L. L6: 2.860 inch = 72.64 mm
Barrel Length : 24.0 inch = 609.6 mm
Powder : IMR 4831

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 83 51.60 2408 2317 33632 8575 96.3 1.541
-18.0 85 52.89 2464 2427 35827 8789 97.1 1.501
-16.0 87 54.18 2520 2538 38165 8991 97.8 1.462
-14.0 89 55.47 2576 2652 40654 9179 98.5 1.424
-12.0 92 56.76 2631 2767 43304 9353 99.0 1.387
-10.0 94 58.05 2686 2884 46125 9511 99.4 1.348
-08.0 96 59.34 2741 3002 49128 9652 99.7 1.309
-06.0 98 60.63 2795 3122 52328 9776 99.9 1.271
-04.0 100 61.92 2849 3244 55737 9883 100.0 1.235 ! Near Maximum !
-02.0 102 63.21 2902 3366 59372 9973 100.0 1.200 ! Near Maximum !
+00.0 104 64.50 2955 3489 63250 10059 100.0 1.166 ! Near Maximum !
+02.0 106 65.79 3007 3614 67391 10142 100.0 1.134 !DANGEROUS LOAD-DO NOT USE!
+04.0 108 67.08 3059 3739 71816 10222 100.0 1.103 !DANGEROUS LOAD-DO NOT USE!
+06.0 110 68.37 3110 3866 76549 10298 100.0 1.073 !DANGEROUS LOAD-DO NOT USE!
+08.0 112 69.66 3161 3994 81617 10371 100.0 1.043 !DANGEROUS LOAD-DO NOT USE!
+10.0 114 70.95 3212 4124 87051 10440 100.0 1.015 !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 104 64.50 3054 3727 75389 9676 100.0 1.086 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 104 64.50 2804 3142 51292 10358 98.3 1.275

 

[sithlord6512]

Thanks DrMIke,

I will post my results as soon as possible. Truth be told, sort of hoping they don't work out too well - hate the idea of spending $37.99 for a box of 20 bullets. However, I will enjoy shooting my "gift" bullets.

 

[DrMike]

With only 40 bullets, you won't do a lot of load development. That is why I still have several boxes on my shelves. I don't even want to get into them. They are something like TBBC once ATK took over manufacturing. I simply don't buy they anymore.

 

[sithlord6512]

I don't know if this is valid, but I thought I would "cheat" by using the data I have obtained from my 180 g TTSX load development.

My plan
1) determine the most accurate 180 g TTSX load for each of the 5 powders I have tested (H4350, IMR4831, IMR4350, N560, & RL17)
2) load 3 rounds with the accurate load, but using MRXs instead of TTSXs (for a 3 shot group) - the Quickload data that DrMike has so kindly provided to me indicates that my most accurate TTSX loads should be safe to use with the MRXs. If the theory behind the OCW method is valid, I would expect that the most accurate TTSX load would probably be the same/nearly the same as the most accurate MRX load.

However, to be extra safe, I will also load 4 "safety check" rounds by doing the following:
3) Subtract 1 grain from the most accurate load and make 1 round, Subract another grain and make 1 round and repeat until I have 4 rounds (with the last load made being 4 grains below my most accurate 3 round load - a total of 7 bullets)
4) Finally, I would then work my way up to the "hottest", 3 round load, watching my chrony (and using the DrMike's QL velocity data to guide me) while also looking for pressure signs at each step along the way. At the end, I would have fired 7 rounds for each powder (35 rounds of MRXs)

5) I would then reshoot the most accurate load tested using the remaining 5 MRXs (the first 3 rounds fired would be measured, then the remaining 2 would be fired and the 5 round group measured ). IF the 3 round MRX groups are better than the groups I achieved with the TTSXs, I am in trouble (i.e., I would have to seriously reconsider my earlier decision to not use MRXs).

I got the idea for this approach from a article by Ron Spomer titled "Finding good game loads quickly". If you have any thoughts on why this approach may not work, please let me know - I am still a relative newbie.