Need advice - 6 ARC bolt action load data for 103-108 gr bullets

[Mr. Wolf]

(edited: Retitled for subject accuracy)
Time to draw up plans for a winter project.
A few years ago, I wanted to really get into the 6 ARC in a bolt gun but I wasn't fond of the temp sensitive powders (CFE223 and Leverevolution) folks were using to get to 2900+ fps. My goal is to reach 2800+ fps with a 26" barrel, 1:7.5 twist, bolt action using Hornady 105 gr BTHP, Alpha OCD brass, CCI SR magnum primers, and Winchester Staball Match powder.

With the release of Winchester Staball Match in Jan 2023, the new powder got my gears turning again. Staball seems to slot between Varget and CFE223 in the burn rate chart and temp stability tests show reasonable stability for the Staball XX line of ball powers.

Anyone with experience on with similar combination with getting their ARC bolt guns with 105 gr bullets to 2800+ fps?
Any available info for max pressure and expected velocities on QuickLoad?
Link to Rob's reloading test with 105 gr BTHP and 28.5 gr Staball Match on a 22" rifle got 2699 fps and SD 16.5.

(Hornady's site doesn't list Staball Match reloading info and Hodgedon's site doesn't have bolt gun info nor the 105gr BTHP listed)

Thank you in advance and happy shooting

 

[Defender32]

Hogdon will only give you data on the 6 ARC to the AR MAX Pressure.

I would load 3 at 27.6 and see what my velocity is and work up from there. You will not have issues getting the speed. The accuracy of the load could be the issue. I am at 30.2 of CFE 223 for my 112 Match burners in a 22" & 26" barrel. If my ammo is kept in my pack on hot and cold days my velocity does rise. I have a temp table of that ammo built 10* to 120* and my data lines up great to 1275. I typically get to shoot 2 PRS Matches a year due to all my rimfire matches.

22" Barrel is 2700 FPS Average
26" Barrel is a 2820 FPS Average.

The 22 ARC and 6 ARC are hunting calibers for me mainly w/ a match at random.

 

[Mr. Wolf]

Defender32
Good info, thank you.
I've read that Hornady 108gr ELD-M Match and 105gr Black ammo exceed their listed bolt gun data.
I'm sure that they load with a margin of safety since there is a good chance that someone will use it in a converted AR-15 setup.

Anyone aware of what powder the Hornady box ammo use?
When my ammo and dies arrive, I hope to deconstruct it, weigh the charges and attempt to replicate best I can.

Appreciate the advice, keep 'em coming.

To carry the conversation along, I'll drop this recoil energy calc graph from ShootersCalculator.com
If 2850 fps can be safely reached with a 26" barrel, it may translate to an advantage to consider for PRS type shooting.

 

[Defender32]

Hornady uses a special blend of powder that is not available to the market. Or this is what I have been told/ heard.

 

[RyanWW]

Hornady black line is aimed at semi auto Rifles.

 

[Mr. Wolf]

Agree, black line is geared towards the AR platforms, but even the 108gr Match has AR-15 platform in the product description.
Typically, gas gun pressures maxes out at 50k psi and bolt guns go higher to 62k psi.

So if the Hornady box ammo is designed to top out at 50k psi with listed 24" barrel resulting in a muzzle velocity of 2750 fps, it stands to reason that there may be some headroom for speed for a bolt gun. I've read that some have seen higher velocities from the factory ammo with longer barrels. However, I've not seen any temp stability testing with the Hornady ARC box ammo. Hope to do that as well concurrently during load dev.

Some suspect that Hornady might be sandbagging the load data to sell their ammo.
I'll be doing tests with Alpha brass and CCI 450 magnum primers or possibly disassembling and reusing the box ammo powder for a ladder test.

Appreciate the info/advice.

 

[RyanWW]

I'll be following this closely. I hope to try staball match in my 6mm arc.
If it helps I get 2580 fps with hornady factory 108eldm and 2560fps with 105 black. Out of 16" bolt gun. Both shoot lights out at 500m but the match is more consistent.