Help me understand this?

[littletoes]

I think you've hit on it, that the temps were just right, and barely that for this load to work.
I may try these loads again on Monday after work to 400 yards, just to see.

In your first example, and just for clarification, I haven't looked at the 68 grain Hornady's, but are they Secant ogive's?

Second example, I talked to Walk Berger years ago, and he assured me his 185's would stabilize in a 1/12 twist barrel, but as you say, over that and its a no-go.

Thanks for the discussion, you hit on the information I was thinking on.

 

[Laurie]

In your first example, and just for clarification, I haven't looked at the 68 grain Hornady's, but are they Secant ogive's?

Yes, although not very aggressively so. The main difference from the SMK is that they're nearly a 10th of an inch longer. Returning to the previous 70 degrees, 27.3" Hg pressure example, the Sg is only 0.81 in a true 1-12" twist at 3,000 fps MV. They really need a full 1-9" twist barrel, 1-10" stabilising them under these conditions, but without a lot of leeway. Miller, JBM Ballistics and other formulae / programs are guides rather than hard fact, but they won't be desperately 'out'.

I can't understand why Remington still makes the VS and SPS Varmint with the slower twist. The SPS Tactical / PSS 1-9" gives a lot more flexibility and still shoots bullets as light as 40gn very well as long as they aren't the very thin-jacket models designed to expand at .22 Hornet and .222 Rem velocities.

 

[littletoes]

ABSOLUTELY AGREE!

The only thing I can come up with, Remington must be directing towards the short range prairie-dog crowd. Guys that are only interested in the 40 grain projectiles.

My problem, I'm a lefty, and hung up on Remington's, so I'm stuck until I can afford a custom barrel. And I just can't see throwing a good barrel away until groups start opening up.
This particular rifle just loves the listed load in the Sierra manual using a 52 grain Match King and H335. I've been consistently producing groups at and under 1 3/4" at 400 yards. At 600 yards, the wind can be a real "training" tool!