"Comments from the lab" re: 7mm 140 gr. E-Tip

[pharmseller]

I received a bunch of 140 gr E-Tips to load for my 7mm-08. Nosler included a note from the lab recommending that I start with the minimum load and not to exceed the mid load.
Why? I get starting at the min load, but why include a max if I shouldn't exceed the mid load?

I use Big Game and Varget. What charges should I try? What velocity (from a 24" tube) should I expect?

Thanks,

P

 

[Guest]

The reason they include that "stop at the mid" bit is because the E-Tip exhibits different pressure characteristics from their lead core bullets, and all the published data up to this point is for lead core stuff. I'm hopeful they'll provide E-Tip specific load data in Nosler #7, which should come out in a year or two, I suspect.

 

[DrMike]

pharmseller, Welcome to the forum. That is a great question, and dubyam has hit the answer square on. Velocity will not vary much from cup and core bullets, even at the mid-range charge. The idea that you get a big velocity increase for the final two grains of powder, especially on most standard length and magnum cartridges, is in error. The efficiency doesn't increase as the charge goes up.

 

[JD338]

pharmseller

Welcome to the forum.

The E-Tip has a long bearing surface and pressures spike very quickly, that is why Nosler recommends the mid range load as MAX for the E-Tips. Because the E-Tip runs at higher pressures, you should still get to the MAC cup and core bullet velocities with the mid range loads.

JD338