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+--- Thread: 6Arc, 1x 105 Factory specs and handload ladders (/showthread.php?tid=59)
6Arc, 1x 105 Factory specs and handload ladders - grayfox - 08-09-2020
I thought it might be helpful to share some initial brass measurements before and after firing, for these first ones from my 20" faxon barrel.
I have the first 11 cases fired, from the Hornady 105 factory bthp. As from my other post I got 2664 average MV out of these.
As close as I could measure, the case of the unfired round is 1.483", pretty uniform (5 cases). The "B" datum (0.350) measures 1.181" (Saami spec is 1.190-0.007").
The fired, unsized cases came in from 1.484 (1), 1.486, most 1.487 (4), then 1.492 (3), 1.493, 1.496. Datum points (no particular order) were 1.1895, 1.190 (3), 1.1905 (3), 1.191 (5).
I set my Hornady resizing die and sized to datum (shoulder) 1.185-1.186 (about 50-50 as measured), which will be 0.003 for the smallest, to ~0.005 for the majority. The hornady die is a little tricky for me to set so I'll leave it at this -- it's pretty much where I've been re-sizing most brass for my shooting.
I resized the 5 exceeding 1.490 to 1.485, and chamfered all 11.
Now for 2 powder ladders I plan to do:
1, with CFE
1, with 2520. I debated for a bit on this one or use TAC or 8208xbr, but settled on 2520 for now.
I will be using my 103 Eldx and hornady data.
CFE, 27.0, 27.5, 28.0, 28.5, 29.0, 29.5
AA 2520, 26.5, 27.0, 27.5, 28.0, 28.5
I will graph the results and look for node MV's.
RE: 6Arc, 1x 105 Factory specs and handload ladders - Dino11 - 08-09-2020
The Cfe has promise per my range day today, don,t even try the 8208 XBR. 8208XBR with Nosler 105's
Even though I went above the spec for 8208XBR, it just did not produce the velocity nor the pressure to cycle the gun reliably. About a two inch drop over factory Hornady 108's, but did group pretty decent but not spectacular.
105 gn. CFE 223 was another story, rifle was cycling, rounds were hitting tight, a little bit low, velocity was down a little with the first ladder of 28.8 gn. but was better than the 8208. Then I stepped up to 29.2 gn and the groups tightend up more and were hitting with the same setting the scope was set at for the factory 108's. I need to set my bullets back a little deeper in the case. This barrel has a tight chamber. I measured the chamber yesterday and compared it to the two faxon barrels I have and the bullets need sto be seated .030 deeper than the other barrels.
I might send this one back to be fixed or replaced. The reason being is I am finding that this round like to be pushed for better accuracy, and I am running out of case volume due to having to set the bullet back. The 108 Hornady that I broke down had 29.7 grains of what looked like 4350 powder. 30 grains of powder looks to be the maximum load, but that is only speculation.
Ultimately I would like to get .045 to .060 bullet jump, but that will require a deep seated bullet on this barrel. Hornady's new 105's are going to be loaded at 2.200. I will post a seperate thread about the measurements I got on all three of my barrels with different bullets when I get a better handle on this.
RE: 6Arc, 1x 105 Factory specs and handload ladders - grayfox - 08-09-2020
My definite feeling after setting up these 2 ladders is that the ball powders will be the best in order to get grains into the case. The cfe at 29.5 does not quite get to the neck, the 2520 at 27, maybe a tad more but less than 27.5, is at the base of the shoulder. All of the loads I set stayed below the neck and were in compressed. The 103 eldx does stick slightly down into the main case, below shoulder but not much.
Interesting that the one you pulled apart is a stick, at 29.7. Was it compressed?
One other comment although based on just a few so only an observation... the primer holes seemed just a bit looser than my typical 1x fired hornady grendels. Not much and no problem but just a smidgeon, since I hand prime I can feel stuff like that. We’ll have to see how this plays out though.
O yes, I did a rough chamber check, at 2.280 my 103’s still had not reached the lands.
I loaded these to 2.260 for the mv ladders.
RE: 6Arc, 1x 105 Factory specs and handload ladders - grayfox - 08-09-2020
Having to go to 2.200 is plain unacceptable and Odin ought to realize that. Especially since other mfrs are getting it right, they will be orphaned out of the mkt unless they own up to it.
It means all seating and jumps are affected, not just the one hornady bthp.
RE: 6Arc, 1x 105 Factory specs and handload ladders - grayfox - 08-16-2020
Dino, re-reading your post, as o by the way, cfe tends to work best when up close to the max... doesn’t like being low in the charge band, from what I’ve seen.
RE: 6Arc, 1x 105 Factory specs and handload ladders - Dino11 - 08-16-2020
I didn't have good luck with the 8208. Hornady tends to list charge rates on the low side, I was only getting in the low 2500fps with 25 gn. Then I loaded some with 28.7 gn of CFE and the velocity went up to the low 2600 to 2700, and the accuracy went up as well.
We'll get this worked out, Hornady's load data is terrible, but unfortunatey it's what we have now. Next time out I will load a ladder.