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08-11-2020, 02:18 AM
6mm ARC revealed by Hornady on June 3rd 2020.
Having a 1000 6mm 90 grain Speer DeepCurls on hand I would have bought in on the day of announcement and went after hogs .... However Hornady provided me with many challenges such as not providing load data, not having components or ammo readily available, and releasing in the midst of an unprecedented peak in gun sales and component sales.
August 10th 2020 - I have a rifle built, I have 100 rounds of factory ammo at the correct overall length of 2.250", and I have dies and components from my own stock/inventory to reload with.
The last two months have been an excruciating wait and I am super excited to get started with this project.
Tomorrow I will setup a chrony and log velocity data and shoot 5 shot groups from this beefy barrel. I did not have an adjustable gas block on hand so I am hoping Proof's CAMGAS system is optimized for the round as it is advertised to be. I'm doing my part by using an OSS Helix Suppressor which is a flow-through design and has little to no blowback pressure.....
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Will be very interested in your results and data!
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Spoke to Travis at Odin Works and Hornady is specing the 105 and 108 grain bullets.
The new spec will be 2.200.
This should be the new fix for the problems I am having with the issue I am having with feeding and extraction.
But I am having an issue with how much powder I can get into a case. My thought is that I need to go to a hotter powder. The CFE223 powder give me better results than the 8208XBR.
What I am seeing is this round likes velocity above 2600 fps.
Travis told me a guy claimed a clover leaf pattern at 500 yards, I got a clover leaf pattern at 300 yards and folks were claiming BS. I have the pics to prove it. Odin is willing to work with me on this. They know their chamber is tight and Hornady screwed the pooch on their ammo spec. Going to try some 4350 powder next time around. it is a little bit on the hotter side, and load to a 2.200 OAL
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Very much looking forward to everyone's results.
After years of listening to people complain about being constrained to magazine length with the Grendel, I'm still having trouble wrapping my head around a 2.20 OAL for this round.
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I really don’t think Hdy messed up, since other mfrs are fine with 2.245 on the 105s. Odins chamber is the outlier. Anyway hope you get your barrel squared away. This is going to be a good round, little cousin to our grrs.
I would add, however, when the Grendel first came out and the 120 was causing trouble, they re-designed to a 123 and BA-Bam!!!
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08-11-2020, 04:49 PM
(This post was last modified: 08-11-2020, 08:21 PM by Pig_Popper.)
So..... this happened today with the new Proof barrel - TWICE .....
My rant...
This should not be happening with factory loads!
I’m sorry but Hornady screwed up big time with the 105 grain BTHP black ammo. They had time to R&D this and supposedly worked with companies to do trials for functionality and development.
It blows me away that Hornady’s invested so much into marketing of the caliber to then send out bad ammo.
I don’t believe 2.200” is the right answer , maybe 2.240” but whatever that really isn’t my concern.
Right now my LaRue trigger is bathing in the sonic cleaner getting all the powder out of the trigger cassette style mechanism.
I’m pissed - a great range day spoiled by bullets sticking into the lands and powder everywhere - had to stick a cleaning rod in the wrong hole twice on my proof barrel.
Now before folks read this and take away that I’m whining and moaning about small matters - let me put this into perspective....
If the DOD received my rifle and these loads and had bullets getting stuck and powder going all over the marksman’s arms and interior of the lower - do you think they’d be understanding about it - do you think they’d be thinking of a renegotiated figure for the contract.....
Anyways , full report later tonight - gotta go clean myself and the rifle ...
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That sucks.
Barrel chambers other ammo with no problems so we can rule out other variables than the Hornady 105 BTHP load?
:: 6mmARC Target Cartridge with Hunting Capability :: 6.5 GRENDEL Hunting Cartridge with Target Capability ::
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We really need that modified case to measure some coal's.
First Odin, then (I think??) cmmg (could be wrong, going on memory here), now Proof...???
My faxon did not do that. I need to put some more downrange but I check-verified lands were clear w/ 105's/2.245 factory before heading out. At the time I had no way of pushing them down b/c didn't have the reloading dies yet... Now I do.
That's bad, PP... what's wrong with these guys???
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(08-11-2020, 05:40 PM)KRYSTOFILUS Wrote: That sucks.
Barrel chambers other ammo with no problems so we can rule out other variables than the Hornady 105 BTHP load?
Well I know that I had checked these when I had the 16" proof barrel and it didn't seem like I was going to be into the lands/rifling - so today I measured 5 factory (105 BTHP) COAL and they ranged from 2.2485-2.2510".
I hand fed these into the chamber and rode the BCG letting it softly come to rest on the base of the cartridge and then used the forward assist to get the bolt closed. 5 out of 5 extracted with little effort.
So this seems to be isolated to full cyclic action of the BCG on the loads and not necessarily a barrel/throat issue with the proof.
I recall in my Grendel reloading experience the Sierra pro hunters would change COAL when sending the BCG home - they are very slick bullets and perhaps the neck tension wasn't strong enough to hold the bullet in place so it would contact the lands/rifling when cycled.
Maybe that is the culprit with these Hornady Black rounds.
I cannot check any other factory loads, these are all that I have at the moment.
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Wow,
Absolutely unacceptable!!! I have a Proof 18" Carbon on pre-order so hopefully shit gets sorted out by November...
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As an interim measure I would recommend using an empty sized fired case with a slit in the neck down to the shoulder to check where the bullets are touching the lands (insert bullet with fingers into case, gently chamber and extract). You can get to within a thou or two with multiple tests. A kinetic bullet puller will aid if the neck tension is too much for fingers to pull out the bullet.
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(08-11-2020, 10:35 PM)Lemonaid Wrote: As an interim measure I would recommend using an empty sized fired case with a slit in the neck down to the shoulder to check where the bullets are touching the lands (insert bullet with fingers into case, gently chamber and extract). You can get to within a thou or two with multiple tests. A kinetic bullet puller will aid if the neck tension is too much for fingers to pull out the bullet.
I had done this already with the 16” proof barrel
I was getting a measurement of 2.255 - 2.2610” when the bullet hits the lands (so very close).
Apparently the forces imparted on the round during live fire are moving the bullet into the lands ....
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I've had that happen in my 6.5 Grendel (bullet moving forward during the chambering process). Using a crimp die helped shorten the jump but to get it to stop the amount of crimp put a groove in the bullet. I polished down the sizing die expander a thou for more neck tension and that seems to work.
For factory ammo you would think they would have this solved before selling them? They need your feedback to make better ammo.
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The above video illustrates the finer points and details from my range trip - for those of you here that just want the straight dish on data and highlights, read below:
Environmental Info:
86 degrees / 74% humidity / 12 mph wind at shooter 6 o'clock / 795 ft elevation / Sunny
Rifle details:
Proof Research Stainless Steel 18" barrel, 1-7.5x twist, Rifle +1 gas system, LaRue MBT 2 stage flat trigger, Leupold 8.5-25x56mm scope
Ammo used:
Hornady Black 105gr BTHP
Magazines tested and observations:
ASC Stoner 25 round 6.5 Grendel magazine - fresh out the retail packaging and into the rifle, downloaded to 23 rounds to avoid max magazine pressure which ordinarily creates a few issues from my previous use of them in Grendel. The mag inserts and drops freely, is of decent build quality, has a clearly marked follower "6.5 ASC". Unfortunately, as is the case with many of my previous ASC mags for Grendel, they just do not run well straight out of the package. And today was no exception, couldn't get a round to strip and feed.
UNIMAG - 24 round wonder-mag - these were developed within the last 10 years, the intent was to carry one mag for a multitude of calibers due to a special patented follower and mag design. The magazine did not insert easily or drop free from the rifle. The follow is not specially marked and loading style is critical in order to get these to function properly, press rounds straight down with two fingers (even pressure). I shot 6 rounds with the UNIMAG and they stripped and cycled fine. Cost and reliability concerns should be noted if pursuing this magazine further.
C-Products Dura Mag - A 20 round magazine design, which is usually the amount of rounds I load into Grendel magazines, give or take 3 rounds based on magazine functionality. The magazine inserts and drops freely from the mag well. Shot about 20 rounds with it and no stoppages. Looks to be of decent build quality and the price is right at under $20 bucks a mag. I will use these in my 6 ARC going forward.
Function of the firearm:
I was extremely pleased by the recoil being so soft yet the rifle smartly cycles and snaps up that top round from fully loaded magazines and gets it into the chamber without any issue. The Proof CamGAS system appeared to be spot on in terms of gas needed to cycle the 105 grain factory Hornady load. All brass was found within a foot spread, 4-5 feet back at the 4:30 position from the shooter.
The barrel did not seem to be effected by heat soak, shots were consistent with point of aim, the weight and balance is slightly forward of the mag release with a full size suppressor added to the mix.
Velocity data:
A Caldwell Chronograph was placed 10 feet from the muzzle and I called out the velocity on video and transferred the reading to my shooting log book when I got back to the house. A couple of rounds were well off the pace, no real explanation for this.
Zeroing and function testing: 2633 / 2626 / 2637 FPS
Group 1: 2619 / 2644 / 2642 / 2634 / 2644 FPS
Group 2: 2643 / 2653 / 2636 / 2633 / 2610 FPS
Group 3: 2649 / 2535 / 2535 / 2630 / 2628 FPS
Brass marks from shooting:
The primers all looked normal, no flat spots or cratering, and there were little to no ejector marks/swipes on the base of the cases. Pretty ordinary looking brass.
Groupings - 5 shot groups:
I had the rifle on a seated sturdy bench, bagged front and rear, view through the scope was comfortable and repeatable. On this given day the best group was .673" and the largest was 1.4" with multiple shots touching each other throughout the groups.
I would estimate that the load is capable of 1.25" groupings from my rifle and that is acceptable for my purposes whether that be plinking at the range or hunting medium to large hogs with it.
Overall thoughts:
After months of waiting to get this build assembled and to the range, I was very disappointed to experience the stuck bullets and powder dumping when extracting cartridges.
My initial thoughts to shoot through the Hornady Black ammo to harvest the brass for reloading is still the primary objective, it just doesn't pay to keep any of this 105 grain Hornady Black on the shelf until things get further sorted out.
Other than that - I did appreciate that the ASC mags didn't let me down, I would say 9 out of 10 mags don't ever run right for me straight out of the package - I've come to accept it and do my tweaks and once they are dialed in they run fine. But for new to the caliber shooters this is going to be an issue for them.
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Great report. Thanks!
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"Other than that - I did appreciate that the ASC mags didn't let me down,"
ASC and ye shall receive (but not chamber)!!! LOL!
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Glad you caught my tongue in cheek on ASC not letting me down
And I see what you did there with ASK (ASC)
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Daddy used to say a little humor never hurt nobody... :p
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Well done on the vid, very good info on the mag performance thanks!
Quote from precisionrifleblog: "article showed an average of 0.004-0.007” of erosion every 100 rounds for popular mid-size cartridges used in precision rifle competitions."
So you may solve the problem just by shooting a few hundred rounds.
Might want to consider the Tubbs final finish or similar products that can rapidly "polish" the throat/lands and get more bullet clearance.
Looking forward to next report and hope for a better range day! 
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Dang PP, sorry to hear you had such bad first range day. Not trying to add insult to injury but I have shot 170 rounds of the 105’s through my cmmg barrel without incident. Do you have a hornady oal gauge? if you do let me know, I have a modified case for the arc, just have to work out the details to get it to you so you can measure that chamber good.
Trashy
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