Thread: 1000yrd load???
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Old January 30, 2013, 12:01 PM   #12
Unclenick
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Join Date: March 4, 2005
Location: Ohio
Posts: 10,195
VegaSSG32,

If these are Berger's secant ogive VLD's, then read this note from Berger about finding the best seating depth. There is no one magic number; this depends on your individual chamber and throat dimensions and other load components.

The Lapua cases may or may not help. I believe it depends on how sensitive your particular rifle turns out to be to bullet tilt, as case neck thickness variations can cause runout on the concentricity gauge. Bart's proven empirically that this made no difference in Palma rifles using the Sierra Palma bullets. He also noted (IIRC; Bart, please correct me on this if I'm remembering incorrectly) that 0.003" bullet tipping didn't make a difference for those rifles on paper, either. But the secant ogive bullets seem to be touchier about this than tangent ogive bullets are, just as they are touchier about seating depth (see the Berger note; I think the two are related, but don't have hard proof at this time). This is why Berger introduced their new "Hybrid" design, with tangent ogive that transitions to a secant ogive beyond the point where the ogive meets the rifling. This improves self-alignment while still achieving reduced drag from the secant profile.

One thing for sure about the Lapua cases, if you run them through a standard sizing die with a standard expander, you are just as likely to pull their necks off axis as any other make, and at that point they don't help you fight bullet tilt any better than anyone else's case does. See this video on the Lee Collet die. You will need something like a separate Redding body die to size the case body down if you use the Lee collet die for the neck.

An alternative to the two-die sizing approach is to buy a Redding S type full length seater die, remove the expander (decap separately or put an undersized expander on it so it misses the inside of the neck) and then select a neck bushing that leaves your necks the right size inside for seating your bullets without an expander being necessary. Lapua brass is very good for this method as the neck thickness is very consistent.

If you have a chamber that is insensitive to bullet tilt, you may want to switch to Winchester brass because it has a little more powder capacity than Lapua for a little bit of added velocity.

If your chamber turns out to be bullet tilt sensitive, you will want to consider the Redding Competition Seating Die. It really does reduce runout. Some have claimed the same result with the less expensive Forster sliding sleeve die. The main difference is the Redding has a floating seater stem to encourage bullet self-centering where the Forster does not, but I have never done a side-by-side between them to compare results. The half sleeves, as are in the Hornady sliding sleeve die are reported not to work as nearly as well as either.

Before you invest a lot in expensive brass and special sizing and seating tools, frankly you would get a NECO gauge or an RCBS Case Master or other gauge system that would let me sort good cases out of new Winchester brass or I would get just get one box of the Lapua cases so you don't break the bank, then use them for initial testing. Get your best seating depth and load established, then drill a hole in your bench the size of the bullet. Stick maybe 16 cartridges. bullet-down in the hole and use your thumb to bend them until your runout setup on your gauge gives you 0.008" TIR (Total Indicated Runout; the range of swing of the indicator hand). This is twice the actual tilt off the case axis. Mark the high reading side on the case head with a Sharpie. Then use the hole to get another 16 rounds as perfectly straight as you can.

At the range, put up two targets. Alternate between them from the bench, putting the straight rounds into one target, and the bent rounds into the other, using the Sharpie mark to index each bent round 90° further around the clock in the chamber than the previous one fired was. Then look to seed if the group fired with the bent rounds is bigger than the one with the straight rounds. Pretty much, it's that simple. If it turns out your gun doesn't care how straight the ammo is, put the gauge away until you start working on a load for your next rifle.

Per what Hummer70 mentioned, I would stay away from 168 grain match bullets with 13° boattails. I have had the Sierra's go unstable in as little as 700 yards out of a 24" barrel and be unable to connect with a human silhouette popper at a measured 748 yards. At Mid Tompkins's long range firing school one year, a whole bunch of us, not knowing any better, brought those and none could even stay on paper at 800 yards with them. All it seems to take is a bit of crosswind, and that bullet's trajectory comes apart below about 1400 fps. Great bullet to 600 yards, but that's really all you can count on getting out of it.

Varget has been an excellent .308 and .30-06 powder for many, but I have to say I see occasional reports from someone who just never finds a sweet spot load with it for a particular bullet. I don't know why, but I do know that I don't see similar reports for IMR4064 in either .308 or .30-06. There always seems to be a good load that powder in those chamberings for bullets in the 150 grain to 200 grain range (assuming the gun is in good shape). IMR4064 seems to be more immune to charge weight error and temperature change in those two chamberings than other IMR powders I've tried, and is often better than many of the more modern formulations for temperature immunity.

The Tula primers Bart suggested are terrific and inexpensive. I've had some ridiculously low velocity SDs using them with IMR4064 and Varget, both. I'm talking single digits even into low single digits in a couple of test runs. A little harder to seat than average, but if you set your primer seater up to seat them about 0.004" deeper than where the anvil feet first touch down in the primer pocket (hard seating) they can be astonishingly consistent. I think Slamfire has a post showing the Wolf primers do much the same. I've seen it suggested they are made by the same plant, but haven't got verification of that.
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