6.8 SPC Range Time (UPDATED)

Measured my 22″ heavy 6.8 chamber with a Hornady OAL gauge. Several bullets measured out as follows:

Sierra 115 SMK

  • 2.384″ OAL to lands
  • 2.352″ for full neck engagement

Berger 130 VLD

  • 2.471″ OAL to lands
  • 2.381″ for full neck engagement

Nosler 110 Accubond

  • 2.407″ OAL to lands
  • 2.457″ for full neck engagement

Nosler 130 Ballistic Tip

  • 2.563″ OAL to lands
  • 2.572″ for full neck engagement

Interesting that the Nosler bullet shapes are such that the bullets seat deeper when into the lands than the maximum length for full case neck engagement. In the end I decided on the Berger 130 VLD for range testing. My loads are from Western Powders and I went with Accurate LT-30. They list the following load data

  • COAL: 2.350″
  • 23.4 to 26.0 charge weight
  • 2158 to 2404 fps

I went with a COAL of 2.38″ and ran loads of 23.9, 25.0, and 25.7 grains. I’m far enough from the lands to expect no significant pressure increase and I have plenty of case space at this loading depth for the given loads. I measured the muzzle velocity at 2300, 2395, and 2475 fps respectively for the three different loads. The 25.7 load charge gave me this 10 shot group at 100 yards:

Not bad at all! I was having some issues with this rifle and factory ammo, and I thought I’d try loading long to see what I could get. The COAL is much longer than mag length, so I had to individually chamber each round. I was shooting a Mega side-charge setup, so I was using it like a single shot, straight-pull, bolt action rifle. Statistics worked as follows:

  • Mean radius: 0.404 MOA
  • Extreme spread: 1.21 MOA
  • Sigma: 0.322 MOA

UPDATE: I inadvertently counted the outlying shot twice. After correcting the statistics look like this:

Definitely very good. On the other hand, the weakness of even a single 10-shot group is apparent in the 95% confidence intervals. Still this rifle with the given hand load is at worst Class 4, and Class 3 is very likely. In this case, the likely P1x for this combination is 0.59 MOA for the estimated Sigma, and at worst about 0.85 MOA. I need to put more rounds down range to get a tighter estimate, but things are looking good.

Solid BACS class 3 rifle with this load. I’m going to load these to PRI magazine length right at 2.30″ and see what I can get next time. Here’s a shot of the rifle from an earlier session, although now it’s wearing a PRS stock and Vortex PST scope:

Ben squinting his way through a nice 105 yard group

For next time, I thought of backing off the powder a bit and load to mag length of 2.300″. You can see the difference below between the 2.38″ and 2.30″ rounds:

I’m especially curious what velocity and accuracy I’ll get with the reduced COAL. The loading manual states 26.0 grains of LT-30 at a COAL of 2.35″ and I only went to 25.7 grains at 2.38″. I think given that at 2.26″ they state 25.1 grains is max safe load, that I can keep this load at 25.7 grains at 2.30″.

I’ve also worked up some 2.300″ loads of Benchmark under 115 Sierra Match King bullets. I want to run this load in my Fulcrum and Recon barrels. Here’s the round compared to a factory Remington 115 BTHP:

Range report this coming weekend.