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Taking the new CVA Scout 2 pistol in 6.5 Grendel to the range again along with some other firearms, I wanted to try a couple of loads from the Sierra Manual for the 107-grain TMK.
I am suffering from a powder shortage at my house, and the only ones I had on Sierra's page for this bullet were H4895 and H4198.
I loaded 10 rounds of:
Nosler case, CCI 400 primer, 24.0 grains H 4198, Sierra 107 TMK loaded to COAL 2.260.
Two five-shot groups gave me less than an inch of horizontal dispersion in 10-15 mph wind directly from my left, but the first target strung vertically four inches and second two inches.
I think part of this was my fault for having an inconsistent rest and too large a bull on the target for the Burris 2-7 at 5X -- five inches, NRA 25-yard slow-fire pistol target, as these are what I had on hand.
But I suspect the pistol just doesn't like something about this load. I had gotten much smaller, rounder groups -- 1 3/8 or so -- with PPU 110-grain FMJ factory loads -- on a previous range visit.
The other 10 loads were the same except 24.5 grains of H 4198. The maximum Sierra load was 24.8 grains in Hornady brass with a Winchester WSR primer.
The first shot struck lower but in the same vertical plane, but the pistol took an effort to open and the primer was cratered so I stopped there. No more of those loads for this pistol.
I normally start well below a listed maximum load, especially with components that differ from the ones used to establish the published data, so I had the pressure signs coming. One reason I started near the top end was that the Sierra data did not specify bolt gun vs AR pressure ceilings the way Hornady has released two data sets for the 6mmARC -- AR data to 52,000 psi and bolt data to 62,000.
Sierra developed the Grendel data with a CZ 527. Why would I assume the CVS Scout could take the higher pressure ceiling? Because it is also offered in .243 Winchester.
Anyway, I engaged in a whole lot of extrapolating and second guessing, partly based on more than 50 years of handloading. I shouldn't have.
Now, one cratered primer isn't the end of the world, but I have generally been conservative with loads over the years; it seems one is never too old for a lesson.
I am suffering from a powder shortage at my house, and the only ones I had on Sierra's page for this bullet were H4895 and H4198.
I loaded 10 rounds of:
Nosler case, CCI 400 primer, 24.0 grains H 4198, Sierra 107 TMK loaded to COAL 2.260.
Two five-shot groups gave me less than an inch of horizontal dispersion in 10-15 mph wind directly from my left, but the first target strung vertically four inches and second two inches.
I think part of this was my fault for having an inconsistent rest and too large a bull on the target for the Burris 2-7 at 5X -- five inches, NRA 25-yard slow-fire pistol target, as these are what I had on hand.
But I suspect the pistol just doesn't like something about this load. I had gotten much smaller, rounder groups -- 1 3/8 or so -- with PPU 110-grain FMJ factory loads -- on a previous range visit.
The other 10 loads were the same except 24.5 grains of H 4198. The maximum Sierra load was 24.8 grains in Hornady brass with a Winchester WSR primer.
The first shot struck lower but in the same vertical plane, but the pistol took an effort to open and the primer was cratered so I stopped there. No more of those loads for this pistol.
I normally start well below a listed maximum load, especially with components that differ from the ones used to establish the published data, so I had the pressure signs coming. One reason I started near the top end was that the Sierra data did not specify bolt gun vs AR pressure ceilings the way Hornady has released two data sets for the 6mmARC -- AR data to 52,000 psi and bolt data to 62,000.
Sierra developed the Grendel data with a CZ 527. Why would I assume the CVS Scout could take the higher pressure ceiling? Because it is also offered in .243 Winchester.
Anyway, I engaged in a whole lot of extrapolating and second guessing, partly based on more than 50 years of handloading. I shouldn't have.
Now, one cratered primer isn't the end of the world, but I have generally been conservative with loads over the years; it seems one is never too old for a lesson.
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