Hornady Factory OAL Concerns

[Dino11]

Hornady specs the OAL to be 2.245, The factory 105 grain bullets that I recently fired through my gun measured 2.245-2.247. The bullets are to long at this unit of measure. They would stick in the chamber and have to be mortared to get them to eject with the unfired case. The bullet is getting pushed into the rifling upon loading. They would eject when fired.

I read on the internet where others were having the same problem, but the bullets was staying stuck in the chamber and just the case was ejecting spilling powder all over the place. Hornady is aware of this issue and the next batch of bullets will be shortened to 2.220-2.230. I am going to load some 108 ELD's today and report back with my findings. The cases that I resized and primed last night go into the chamber and fall right out when you tilt the rifle, these are the same cases that were getting stuck with the bullet in them.

I will start with 2.245 and shorten them in .05 increments till they do not stick. I really should get this camber measured to know what length will be optimal for maybe a .10 lead jump.

I spoke to the folks at Hornady yesterday and they have started production of the 108 grain loads and they said that they should start shipping the first week of August. The 105 loads are later in the month and should be available the end of August. Don't kill the messenger if this doesn't happen... this is what I was told by them.

[grayfox]

I talked to a barrel mfr (Sanders) couple of days ago and he told me that this was happening, with the mfr 105 ammo... at the time I couldn't find anyone else talking about it.
So this is good to hear an independent confirmation.
Does make me wonder "what were they thinking?????" when they made a chamber and some 105's that would do that.
Almost begs the question whether the throat/leade/whatever is really long enough for these high-BC bullets.
If the 105's are coming end of August then sounds like the 103 Eldx's will be later than that. That's pushing it pretty close to hunting season!!

---

According to Sanders, for the factory loads you should be able to just seat them a bit deeper, to the 2.220-2.230 (or something) for them to work without jamming the lands.

[Biodsl]

Ammo that Hornady manufacturers won't fit in a proper SAAMI chamber of a cartridge that Hornady designed?

How exactly does that happen?

[grayfox]

I doubt if we will get a good answer to it.

[Dino11]

I have a call into Odin, reloaded some 105's and had to go all the way down to 2.210 to get the rounds to reliably eject pulling the charging handle to eject a live round. I also had to do the same on the 108's. I may have to send this barrel back in to get it reamed, I hope not this thing is the best shooting barrel I have ever owned, and I don't want it to get screwed up. Loaded ten rounds of each and checked every round in the chamber. I guess I will have to wait and see what they say. I have to wonder what the pressure difference will be if I load them to the shorter length, and if accuracy will suffer because of it.

[grayfox]

Can they lengthen out the throat area without changing the barrel much. I didn’t check but wonder if this caliber has the compound throat or a straight one.

[BluntForceTrauma]

Anticipating that many reloaders of the 6mmARC will want to load to a Cartridge Overall Length (COL) of 2.280 rather than the standard 2.260, I had added a touch more freebore to my MONSTER 6mmARC 20" barrels, which are currently in manufacturing and due in November.

Looks like I might have gotten lucky and also helped solve this problem. 

[BluntForceTrauma]

I didn’t check but wonder if this caliber has the compound throat or a straight one.

SAAMI specs for 6mmARC have a standard straight freebore with 1.5 degree leade angle.

[Dino11]

I took some 1000 grit wet dry sandpaper and spun the cartridge in my hand and dulled the bullet and neck. then loaded the round and chambered it, at 2.210 the bullet is just touching the rifling. with the dulled bullet the area that touches turns shiny. It is putting very small marks on the bullet. The longer the bullet the more pronounced the marks become. I don't have a problem with the bullet barley touching the lands, that actually may help accuracy with little to no lead jump. But my concern is the cartridge is .035 short of the SAAMI spec, and what is this going to do with pressure spike. Those first rounds I fired had to be jammed in their pretty good.

[BluntForceTrauma]

Is it possible it's the barrel chambering?

You said other folks have reported it, as well. Same barrel company or a variety?

[grayfox]

From my talks I don't recall which barrel maker(s).
Could have been sanders or could have been odin. But don't really recall if one of those or another.

... Would they do such a thing so as to allow some throat erosion yet still leave the barrel in-field? Wouldn't think they would do that but...

[Dino11]

The problem is with the 105 grain ammo, the olgave is larger on it than the 108's and it will stick in all chambers. This is why they changed the spec on it. I have to wonder if the Saami blueprint is going to change as well. Maybe that is why we have not seen load data on that round, and why they are releasing it late in the month of August. I have 1000 105's and a 1000 of the 108's to load with. Still waiting to hear from Odin about my barrel chamber. You can see a line scored at a twist just about the whole length of the exposed part of the bullet when they get stuck. I can take a small soft blow hammer and just tap on the charging handle holding the release open and it will pop out. It is stuck, but not really jammed in their. It might just be a burr in the chamber and it will shoot out but I can't see anything looking at it with a bore light.

[grayfox]

I just took a sized 6 CM case I have on hand, and a new 103 eldx, and 105 bthp bullet. Stuck each bullet upside down into the case mouth and made a light score with my knife blade, to give a "line" at the base of ogive. Then compared the 2 scores. From the bullet-bases the scores are virtually same distance but the eldx is longer than the bthp, so... since I seat for OAL by the tip, the delta would be a longer, narrow eldx sticking into the bore. My eldx measures 1.264 and the bthp 1.220 (JBM has the 103 eldx at 1.258).
I don't have any 108's.
So a coal of 2.220 for the bthp could run out to 2.264 for an equivalent in the 103 eldx.

If I'm doing this right...

If someone has some 108's try to find the coal diff a 108 would seat at, given the "bthp" chamber sizes we're talking here.

[Trashy]

Here are the measurements I got from a couple of factory 105 bthp's, cbto 1.740" & col 2.250" using hornady comparator bushing 3-24. The headspace was set at 1.182" & 1.180 " using the hornady headspace insert B-350. Saami headspace shows to be 1.190 - .07

These rounds are sticky on manual extraction and show flat primers and ejector swipes in my rifle, i listed the chrono data on another threat so there is no need to repost it here. I got my brass so I am done with them, I'll trust my own hands and gauges from this point forward. Hope this helps

Trashy

[Dino11]

Just got off the phone with Odin Works... Hornady told them to load the rounds @ 2.200 with no signs of pressure issues with the current load data. So I am going to go reseat all my hand loaded rounds to this spec and try to get out to the range this week. If this works out I am going to reseat all the factory stuff I have. If it does not work I will be contacting Hornady to have the ammo replaced with known good ammo. Wish I could get my hands on a new box of the revamped stuff to get a measurement from it.

I loaded both 105 and 108 with 25 grains of 8208 and plan to chrono them this time around.

[Pig_Popper]

Using a Proof stainless steel barrel - and a modified case that I cut to be able to manipulate OAL Of the bullet while the Case is in the chamber 

I’m getting 2.2615” to the lands with a Hornady Black 105 gr BTHP

Also I measured 5 factory rounds and they varied in COAL from 2.2465” - 2.2525”

So I’m thinking Proof barrels are Ok with current 105 BTHP Hornady black loads .....

[grayfox]

Odin is starting to sound a bit short in the throat...

When I get my Proof 18 in, I'll certainly be measuring and report.
It's in the usps hands, priority mail so hopefully by Friday...

[Dino11]

I reseated my hand loads to 2.200 and the rifle now functions as it should. I did both 105 and 108's to see how they fair. At least now I know what my maximum length is @ 2.210 before I start pushing the bullet into the lands. .010 off the lands is very acceptable and gives me a little room to play with. Once you get your Proof barrel running and can chamber a round keep us posted on your results. I so wanted one of the stainless Proof barrels, but the wait time I was told was very long.

That Proof barrel has a lot of lead jump.

[grayfox]

Don't think we've heard from cmmg or BA barrels, if someone has one and could report that would be a help.

[Biodsl]

Wasn't it Proof that provided the barrels for the military tests? Perhaps they know something Odin didn't.