Factory Loads: 6.5 CM 147 ELDM Faster Than 140s?

[vh20]

I've been running factory Hornady 140 ELDM factory loads through a new 6.5 CM build for the past month, and have about 100-150 through it so far. I just bought some of the new 147gr. factory loads to compare and found something unexpected. My MV AVG (Labradar) with the 140s has been pretty consistent in the mid-2750s over many rounds measured (26 in. Krieger 1:8). Today I shot a 5 shot group of the 140s through the chrono and was in the expected mid-2750s. Then I shot two 5-shot groups with the new 147s and found my MV AVG to be HIGHER at 2790! This doesn't match expectations, nor published factory data. However, after getting the observed data into the Kestrel and going out to the 1000 yd target, it calculated a 7.68 mil elevation. I set elevation at 7.7 and fired two rounds, and noted impacts within a few inches of each other, about 0.2-0.3 mil HIGH. Next I came down to 7.5 mil elevation and fired three rounds into a 9 in. group that went from 0.05 high to 0.2 low. I don't have the exact number calculated for the 140 under today's conditions, but it would have probably been around 7.8 - 8.0 (DA was around 1500).

In other words, not only did the long range data confirm the higher MV of the heavier bullet, but it even out-performed the computer with the observed MV included in the calculation. There is the factor of mirage going on that may have accounted for the slight 0.2 discrepancy, but nevertheless, the higher MV of the 147 was definitely confirmed at distance over the 140. I really never expected that. Anyone else notice it?

Downside: Freakin' ES was about 60! I really wish they'd get a handle on that!

 

[Blowby]

Check the MV on the 140's now to verify if it's really is the factory 147's or the increase is the new barrel coming up to speed.

 

[vh20]

I shot a 5 shot group of the 140s over the Labradar immediately before shooting the 147s. The 140s gave the same velocity they always do, and the barrel had about 150 or so on it at the time. The 140s were in the high 2750s as usual, and the 147s averaged 2790. I shot another 15 this afternoon, and got an AVG of 2805. ES was 68 though!