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7X57

20 Jun 2017
@ 10:25 am (GMT)

James Westerheid

Just finished reading your spot on this cartridge. I have a 7X57 my dad built up in 1972. 24 inch Douglas Barrel, 3 stage trigger ( unknown manufacture) and Mark II Model 98 long action. With 52 gr R19/CCI250 primer/Nosler brass/150 gr Nosler Silvertip. I am getting 2922 fps over the Caldwell chronograph @ 7 feet out. 6 shots SD of 10 and ES of 16. I see no signs of pressure. This is a full to slightly compressed load. The bullet is only seated at about one caliber depth. The neck is just over two calibers. and 0.035 jump. Grouping under 1MOA off the bench.

This load is 1 gr over the Nosler Manual max and I snuck up on it. The gun is almost 2 lbs lighter than my M77 7 Rem Mag and only 175-200 fps slower. I know this is a hot load. I must be careful with high ambient temperature. But the sheep hunt I am planning to use this on will have ambients around those during load development.

Do you have anything to add???

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20 Jun 2017
@ 11:02 am (GMT)

Nathan Foster

Re: 7X57
No real need to comment but for the sake of other readers, an explanation of why the velocities are high may be useful.

Most Chronies cannot work well at this range, the readings are not just misleading but often non-existant. You might have found this out had you been using a copper jacket but the Chrony is picking up on the black jacket. Still, I suggest you move to 12 feet, double check alignment, then recheck velocity and ES.

But the big boost you will be getting is via the coating on this Winchester spec version of the BT bullet.

The seating depth is such that generally a fast cycled Mauser will bump the bullet out of alignment. But yours appears to be doing fine if its under 1 MOA and provided it maintains this when magazine feeding in the field.

If you seat off the lands to Nosler's specs, the velocity will drop. Although in this instance, it will increase again as you head towards powder compression (pressure rises as we push to the extremes in either direction).

In any case, if its working, then all is well and there is no need for me to comment. The RL19 burn rate can prove useful but as suggested, the bullet coating is a major part of this equation, plus the chrony location.
19 Jul 2017
@ 07:13 am (GMT)

James Westerheid

Re: 7X57
Thanks for the reply. I have double checked this. My Caldwell against a MagnetoSpeed. Two different technologies. The MagnetoSpeed reads 40-50fps slower than the Caldwell. ES and SD statistically the same as Caldwell. So at worst I am getting 2880 fps with the 150gr Nosler Slivertip. Velocities are not statistically any different with the regular NBT.

I try to keep the Caldwell out of direct sun because of sun angle at the range. But I've shot several hundred rounds over it. Nobody wants to believe that this little round will go this fast but it does. 270 Winchester territory! The real proof will be at long range soon.

Supposedly the velocities are to be more repeatable with the Silvertip. I cannot verify this. There is however no copper fouling. Next up is the Hornady 150gr ELD-X. But now I am micing a brick!!! But the ELD-X has a higher BC and thermal deformation resistant metplat. It also seats farther out before contacting the lands.
19 Jul 2017
@ 07:24 am (GMT)

James Westerheid

Re: 7X57
One more thing. I have cycled the action on these loads and using the Hornady Concentricity Tool I get up to 0.003 off center alignment. I can live with that. The action and magazine are so long that Dad put an aluminum spacer at the front of the magazine to keep the cartridges at the back of the magazine.

The nice thing about the 7X57 over the 7-08 is the longer neck as well as more capacity.
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