Hornady "Black" and "Match" Factory Ammo - Hmmm!

[Black9]

So I got in some of Horandy's factory "Black" 6mm ARC ammo (105 gr BTHP) and their "Match" 6mm ARC ammo (108 gr ELD) and after a go over of it before starting actual range testing (i.e. shooting them), all I am going to say is Hmmmm!

The "Black" ammo is loaded at right around 2.200" OAL which gives the bullet a jump of just about .040" to the lands on a SAAMI 6mm ARC chamber (at least the one I have).

The "Match" ammo is loaded right around 2.250" OAL which also gives the bullet a jump of just about .040" to the lands on the SAAMI 6mm ARC chamber (at least the one I have).

I pulled down a number of cartridges to measure the powder loads and just to see what was going on inside and here's what I found:


Both the "Black" and the "Match" are loaded with a ball powder that looks like a dead ringer for Hodgdon's CFE223 and the loadings also bespeak of a powder of a similar burn rate.  In addition, the loads of both are under heavy compression.  To get the powder out of the cases after pulling the bullets, I had to hold each case horizontally over a metal cup and insert a wooden toothpick in the case as I spun it to break up the solid chunk of powder in the case caused by the compression.  Even then, the powder came out with clumps of the powder stuck together from compression.  IMO - not exactly the recipe for accurate loadings (i.e. ball powder under heavy compression).

The loading of the "Black" varied from 30.12 gr to 30.38 gr..
The loadings of the "Match" varied from 30.58 gr to 30.60 gr..


Robert

I just picked up one box of Hornady's Black and one box of Hornady's Precision Hunter 6 ARC bullets on 1 July 2022. Did a comparison like you but not as in depth as you.

The 'Black' was loaded with 27.12 to 27.31 gn (using only 5 bullets) of powder. COAL was 2.206"
The 'Precision Hunter' was loaded with 24.96 to 25.18 gn (using only 5 bullets) of powder. COAL was 2.255"

All loads were heavily compressed as I had to use a toothpick to remove the powders.
I used my microscope to look at the powders of each including CFE223 and Leverevolution. LVR and CFE223 look similar under the microscope there were a few subtle differences. The powders in both bullets seem to resemble CFE223. Although that is not a definitive answer it gives me a starting point.

That's a rather large disparity from what Robert found originally. Is there any way that you could follow up with chronograph results?

[gorillamotors]

Yep. That is why I only did that to 5 bullets each. I have to go to the range either this week or next to fireform some Lapua 6.5 Grendels to 6 ARCs. 
Jim