Any experiences to reload the 6x70R?

[gunner]

Hi to all,

a friend has a nice hunting rifle made at Ferlach and it has the rare caliber of 6x70R. It is looking like smaller .303 Brit. and he mainly uses a 85 grs. bullet. Now the problem, one of the two makers of this round won´t produce it any longer. The other wants to have $ 110 for 20 rounds. Now we bought a RCBS Die-set and the Barnes TTSX in 85grs. Does anybody have or know a source where to get good load datas? most german sources say that they are using VV powders like N135, N140 or N160 but without the datas.

Can anybody help me at there?

TIA

Information

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[Parashooter]

That's a strange one, indeed. QuickLoad includes 6x70R among its tables. FWIW, here's a sample of estimates -

Cartridge : 6 x 70 R
Bullet : .243, 85, Barnes 'TSX' BT 24341
Cartridge O.A.L. L6: 3.425 inch or 87.00 mm
Barrel Length : 29.0 inch or 736.6 mm

Predicted Data for Indicated Charges of the Following Powders.

Matching Maximum Pressure: 36259 psi, or 250 MPa

or a maximum loading ratio or filling of 100 %

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 !

Powder type Filling/Loading Ratio Charge Charge Vel. Prop.Burnt P max P muzz B_Time
% Grains Gramm fps % psi psi ms
--------------------------------- -----------------------------------------------------------------
Accurate 4350 98.8 30.9 2.00 2774 93.5 36259 7913 1.437 ! Near Maximum !
Vihtavuori N550 90.7 30.3 1.96 2760 93.0 36259 7797 1.433 ! Near Maximum !
IMR 3031 83.2 25.4 1.65 2759 99.8 36259 6834 1.434 ! Near Maximum !
Ramshot BigGame 89.3 29.2 1.89 2753 94.9 36259 7511 1.428 ! Near Maximum !
Ramshot Hunter 91.0 31.7 2.06 2750 90.3 36259 7849 1.426 ! Near Maximum !
Hodgdon H4350 93.4 30.4 1.97 2747 90.7 36259 7708 1.421 ! Near Maximum !
IMR 4895 84.1 26.6 1.72 2744 96.9 36259 7077 1.408 ! Near Maximum !
Winchester 760 88.6 30.7 1.99 2744 89.2 36259 7719 1.428 ! Near Maximum !
Winchester 748 76.9 27.1 1.75 2742 97.6 36259 7101 1.434 ! Near Maximum !
Hodgdon BL-C2 79.2 28.3 1.83 2733 96.5 36259 7320 1.447 ! Near Maximum !
Accurate 4064 89.3 27.3 1.77 2724 99.1 36259 7069 1.479 ! Near Maximum !
Accurate 2495 82.9 25.6 1.66 2720 100.0 36259 6757 1.484 ! Near Maximum !
Accurate 2520 81.1 27.3 1.77 2719 98.3 36259 7003 1.459 ! Near Maximum !
Alliant Reloder-19 97.8 32.0 2.07 2716 86.0 36259 7687 1.431 ! Near Maximum !
Alliant Reloder-15 83.2 27.2 1.76 2715 94.3 36259 7210 1.450 ! Near Maximum !
Hodgdon H414 84.3 29.4 1.90 2714 90.2 36259 7468 1.447 ! Near Maximum !
IMR 4320 85.1 27.4 1.77 2710 94.8 36259 6995 1.421 ! Near Maximum !
Hodgdon H4895 85.4 27.0 1.75 2709 97.8 36259 6822 1.424 ! Near Maximum !
IMR 7828 SSC 100.0 33.6 2.18 2705 81.7 36172 7881 1.430 ! Near Maximum !

[gunner]

Hi Parashooter,

many thanks for your efforts! Hmm, thats indeed strange and i think i´ll try to start around 2 grains deeper than this load datas are saying. What is your opinion to the powder, should i try the N550 or more the H414 ? it makes sense to use the slower burning ones and i think the burning of the powder is more equal and the pressure will be more equal in his effect to the bullet in the barrel.

[Parashooter]

There are numerous valid approaches to selecting a load for further testing/development. Given that all loads in the sample were calculated for a modest pressure 100 bar below CIP maximum, we might select on several criteria -

• Density - Look for the optimum velocity at near 100% density. The top and bottom loads on the sample are examples.
• Efficiency - Try for best velocity with the least unburned powder. Examples here are 3031 (99.8% burnt) and 2495 (100%).
• Economy - Optimum velocity at lightest charge of lowest-cost powder. Note that 3031 and 2495 are also the lightest charges shown.
• Convenience - Select a powder you already have on-hand or one readily available.

Please note that the data provided is only a small sample (and specifies a 29" barrel). There are many other powders in the QL library that would be equally or better suited to individual needs. Obtain the software, specify your own conditions, and you'll get a much fuller idea of the possibilities. See QuickLOAD Software von - Literatur - Wiederladen - Munition & WL Shop - Frankonia.de

[gunner]

You´re correct with your points! But for the reason that the VV and Hodgdon powders are the ones which are mostly available, i have to use them. Broemels software is good but expensive and for the reason that this is the only "Exotic" caliber i reload ( and that only for the reason that the hunter is a friend) i won´t buy it. And for the external ballistic, i made a better one with the help of some Swiss engineers.
Next is that i have to reach the minimum energy of 1000Joule at 100 meters for shooting deers which is in the laws over here. And i won´t create a borderline round in chamber pressure. I think the best way is to create a accurate round and give it to the Munich Proofhouse to see if it is safe for longer use, that means that it shouldn´t be at the highest levels in chamber pressure.
Seems that you own a CD from Broemels Ballistic Program, is it possible for you if i´ll send you the barrel length that you can give me the results for it???

[Parashooter]

1000 Joule @ 100m appears possible with a moderate load of N550 in a 23" barrel. Estimated pressures are well below CIP Pmax of 2600 bar.

Cartridge          : 6 x 70 R
Bullet             : .243, 85, Barnes 'TSX' BT 24341
Cartridge O.A.L. L6: 3.425 inch or 87.00 mm
Barrel Length      : 23.0 inch or 584.2 mm
Powder             : Vihtavuori N550

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.778% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step    Fill. Charge   Vel.  Energy   Pmax   Pmuz  Prop.Burnt B_Time
 %       %    Gramm    m/s   Joule     bar    bar      %        ms

-27.8   63    1.357    557     854    1096    332     70.1    1.728
-25.0   65    1.409    576     913    1173    352     72.0    1.681
-22.2   67    1.462    595     975    1256    373     73.9    1.635
-19.4   70    1.514    614    1039    1346    393     75.7    1.590
-16.7   72    1.566    634    1107    1443    414     77.6    1.547
-13.9   75    1.618    654    1178    1548    435     79.4    1.504
-11.1   77    1.670    674    1253    1661    456     81.2    1.462
-08.3   80    1.723    695    1330    1784    477     83.0    1.422
-05.6   82    1.775    716    1411    1917    498     84.7    1.382
-02.8   84    1.827    737    1495    2061    518     86.4    1.344
+00.0   87    1.879    758    1581    2217    538     87.9    1.306  ! Near Maximum !
+02.8   89    1.931    779    1671    2386    557     89.5    1.270  ! Near Maximum !

 Tabular trajectory data at Std.ICAO Atmosphere
-------------------------------------------------------------------------------------
 Gun / Ammunition : 6 x 70 R
 Bullet           : .243, 85, Barnes 'TSX' BT 24341
 Bullet weight    : 85 grains or 5.51 Grams
 Muzzle velocity  : 758 m/s
 Crosswind speed  : 4 m/s 
 Ballistic Coefficient(s) (G1): 
 C1=0.333@V>0 m/s;


 Optimum trajectory information : 
 Optimum sight-in range (X) = 149 m 
 with max. ordinate above LOS at range (M)= 81 m
 and max. point blank range (P)= 176 m.
-------------------------------------------------------------------------------------
 Sight-in clicks, 1 click = 1.0 cm/100 m or 0.394 in/100 m
 Height of sight above bore axis = 1.27 cm or 0.50 inch
 Gun is zeroed-in at 100 m,
 by sighting-in at level firing
-------------------------------------------------------------------------------------
 Range  Velo Time of  Energy   Path    Deflection    Total  Sight correction  Target
        city  flight            to    at crosswind    drop   for setting new   lead
                                LOS    of 4.5 m/s              zero range     10 m/s
-------------------------------------------------------------------------------------
·Meter   m/s     s    Joule     cm     cm      MOA     cm    Clicks     MOA      m  ·
-------------------------------------------------------------------------------------
|    0   758  0.0000   1581    -1.3    0.0   -----     0.0   ------    -----    0.00
M   58   708  0.0789   1382    +1.8    1.1    0.62     3.0     -3.2    -1.09    0.79
X  100   674  0.1400   1250     0.0    3.6    1.23     9.2      0.0     0.00    1.40

[Gun Surfer]

All request loads @ www.reloadersnest.com

Here's 4 loads in case this is helpful to you, not sure where these are on the scale of mild to hot though.

[gunner]

Thank you to you both for your great help!

[jon_norstog]

Gunner,

That is some kind of obscure round. If it was me, I would use h-380 and start about 2/3 case full. And wear shooting glasses when I tested the load.

jn

[gunner]

Thanks Jon! I found a load and it worked out very good. It will hold the same POA like the Norma ammo but it is much softer to shoot and the primers are looking good and not so flat pressed like the Norma ones. Load is 23.9 grains of VV N140. And it is very good on deers with this bullet. Entry hole is 6mm and exit hole is a little more than 14mm. No damage on the meat and only a very little hematoma is to find. He shots 3 deers and only one made it to around 15 meters. The others fell in the fire(SP). Thanks a lot to Parashooter for his help with the Broemels program!