IMR7828 & .277 TSX

[Guest]

Just wondering if anyone is loading this combination in a 270Wby? I'd like to hear about your experience, as well as what your start and max loads are, and if you know the published data, that might help as well. Thanks.

 

[Antelope_Sniper]

I've only heard stories, but the 270 Wby is supposed to like IMR7828. The Hodgons has load data for 140-175's here:
http://data.hodgdon.com/cartridge_load.asp
If you plan to use something lighter, they go down to 115gr in Hodgdon Manual. Let me know if you need it.

 

[Guest]

I have the Hodgdon Annual from a couple of years ago, and I have the IMR data for 7828. My concern is what the max load is for TSX's versus what the max load is for lead core bullets, as the two are likely not to be the same. Thanks for the assistance, though.

Oddly enough, I had a great load with 7828ssc, getting about 3500fps from 130gr Hornady Interbonds, but the last time out, they shot all over the place, achieving roughly minute-of-barn-door accuracy. The rifle routinely shoots a 150gr load into less than half and inch, and the 130's had gone into 1.25-2" during load workup. I will be playing around with them, but I picked up some Tipped TSX the other day on sale, and so I thought I'd try them out, too.

 

[FOTIS]

I got 3500 with the 130 AB's but no experience with the barnes.

 

[Antelope_Sniper]

Yes, that is a frustrating experience.
I have the Barnes #3. For the old 130gr xbt with IMR7828 it shows a starting load of 69.5gr at 3161 and a max load of 74.5gr at 3388. Barnes advertises the TSX as generating less pressure then the XBT, so that should at least get you in the right ball park.

 

[Guest]

Thanks for the data. It helps immensely to know what the manuals say regarding the Barnes, as data is sometimes pretty exclusive where there bullets are concerned.

 

[FOTIS]

Cartridge : .270 Weath. Mag.
Bullet : .277, 130, Barnes 'TSX'BT 27742
Cartridge O.A.L. L6: 3.295 inch or 83.69 mm
Barrel Length : 26.0 inch or 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 79 55.20 2687 2084 32685 10123 89.2 1.508
-18.0 81 56.58 2755 2190 34838 10458 90.6 1.470
-16.0 83 57.96 2823 2300 37143 10782 91.9 1.432
-14.0 85 59.34 2891 2413 39609 11093 93.2 1.396
-12.0 87 60.72 2960 2528 42259 11391 94.3 1.360
-10.0 89 62.10 3028 2647 45097 11672 95.4 1.325
-08.0 91 63.48 3097 2769 48147 11935 96.3 1.290
-06.0 93 64.86 3166 2894 51422 12179 97.2 1.256
-04.0 95 66.24 3235 3022 54946 12402 97.9 1.219 ! Near Maximum !
-02.0 97 67.62 3304 3152 58738 12602 98.5 1.182 ! Near Maximum !
+00.0 99 69.00 3373 3284 62825 12779 99.1 1.146 ! Near Maximum !
+02.0 101 70.38 3442 3419 67240 12930 99.5 1.111 !DANGEROUS LOAD-DO NOT USE!
+04.0 103 71.76 3510 3556 72010 13054 99.8 1.078 !DANGEROUS LOAD-DO NOT USE!
+06.0 105 73.14 3578 3695 77169 13150 99.9 1.046 !DANGEROUS LOAD-DO NOT USE!
+08.0 107 74.52 3645 3835 82766 13216 100.0 1.014 !DANGEROUS LOAD-DO NOT USE!
+10.0 109 75.90 3712 3978 88817 13267 100.0 0.984 !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 69.00 3530 3596 76011 12358 100.0 1.059 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 99 69.00 3155 2873 51096 12473 93.4 1.256

 

[Guest]

Am I reading that right, POP? I should consider 69gr to be a max charge? Yikes. I've been shooting 130gr Interbonds over 76gr, as that's the published data from IMR, without pressure signs of any kind. Please confirm that I'm reading it correctly, or correct me.

 

[Guest]

After some checking around, I was able to get data from Barnes for the TSX with 7828. They say that the start charge is 68gr, and the max is 72gr. Velocity ranges from 3113-3347fps, which is significantly below your Quickload calculations, POP. I find that interesting, and I wonder if there is some discrepancy between the actual tested data and Quickload's ability to simulate that powder? Either way, Barnes shows roughly the same max velocity as Quickload, just at a higher powder charge (and one would assume similar pressure, as pressure and velocity are pretty closely linked). At least now I know. I'm going to try some AA Magpro as well, as Barnes said that was their most accurate load.