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Hornady 6mm ARC.
- Thread starter orkan
- Start date
About time. This is what the grendel should have been from the start...
Possibly to make room for the longer 6mm bullets at mag length, but keeping the bearing surface out of the neck/shoulder junction?
Not much point in this if you run a bolt gun. They designed it for AR's. Bolt gun... 6BR and cartridges based on it are king.
I run other chamberings (260...) with the bearing length intruding into the shoulder region, and I've never experienced a downside as far as I can tell.
Still, I keep reading here about how that's a bad thing.
How is it a bad thing, and why?
Greg
Still, I keep reading here about how that's a bad thing.
How is it a bad thing, and why?
Greg
Maybe. Seems like that was already accomplished. The 6mm shouldn’t be any longer than it’s big brother.
Mainly for the potential for the brass to misbehave there, which subsequently causes bullet seating uniformity issues.
I have had cases form donuts and did get vertical issues.
Other than that I never see problems doing it.
Like most things... it's never a problem, until it is.
Could be as simple as a case capacity optimization as well. Sometimes going smaller has some very desirable effects when it pertains to powder burn characteristics with the desired bullet configurations.
Pretty hard to argue the well documented success of standard 6mm PPC. You wouldn't think the smaller capacity than the 6BR would matter much... but in short range high end disciplines... the PPC wins everything, or so it would seem.
I agree that it isn’t much of a practical problem. Many bullets have a pressure ring at the bottom of the bearing surface, which will run into the base of the neck as it passes. This can be exacerbated by donuts at the neck shoulder junction in high mileage cases. Some makes of brass are worse than others. If you’re designing or choosing a cartridge, it’s an easy box to check.
Supposed to make it more VLD projectile friendly. Default round is the 108gr ELD for the DOD spec.
I know you reload, me too so...I'd rather go 22PPC because Norma has factory brass. Probably get 223AI speeds plus some in a AR. Just guessing, 95 SMK at 2600-2700??? That'd be AR awesomeness.
Others disagree but i think the extra capacity of the 6mmART40 and the 6mmFATRAT does help in the wind and it's close to the 6mmBR in "real life". I'm getting 2870 fps/6mm 95gr SMK in my AR FATRAT and 2850 fps/105HPBT with 6mmBR bolt gun.
Bolt gun - I'm having 2nd thoughts with my 6mmBR/2850 fps/105gr HPBT. The reason is I want that 2950 fps/105gr sweet spot without excessive pressure so I'll most likely go 6mmBRA next time.
Once I hear some real world velocities with 20" barrels there is a good chance I'll make an upper in 6mmARC. I think the BR family is the sweet spot for bolt guns though.
You better go with dasher if you want that speed and not be in the high node. That's right about where I'm running my 6 Dasher with H4350 and 105 hybrids. 6BRA can certainly get there, but it will be grunting... and most certainly in the high node.
My little CZ527 Rust/Nitre blue project is in 6 ARC. 8.4lb as pictured. It's a handy little thing. I've made it out to 600yd so far and it's very capable. The intent is a 0-300yd hunting rifle. Bartlein #4 contour (shank buzzed down to fit the action) 4140 5r barrel. Rifle was originally a 7.62x39 carbine.
I would buy this in a heartbeat if CZ started offering it as a chambering.
Made quite a few barrels for Hornady while they worked on this round. Accuracy test barrels, pressure barrels, bolt guns, gas gun barrels etc...all the feedback I got back was all shot nice small groups.
Brady in the shop built a upper in 6ARC as well. Thing hammers!
Later, Frank
Bartlein Barrels
Brady in the shop built a upper in 6ARC as well. Thing hammers!
Later, Frank
Bartlein Barrels
I'll probably go 28" barrel next time too which will hopefully make up 45 fps compared to a 26" which I'm using now. But I'll look into it more. Thanks.
It definitely serves a purpose if you’re someone who likes shooting factory ammo in PRS. Your only real choices are 6.5 and 6 cm.
So, if you’ve wanted to run a 6br, but didn’t because factory 6br ammo was too expensive, this is the answer.
That’s a pretty good point... but I thought that was what 6GT was for?
No affordable 6gt ammo at the moment. Minimum $1.75/rnd.
Hornady 6arc is $1/rnd.
It’s a narrow market. But a new to PRS shooter could benefit greatly. I’d imagine it will get 6br barrel life around 3k rnds.
@bodhisafa
Stripped lower receiver
Lower parts kit
Receiver extension (buffer tube)
Buffer
Buffer spring
Castle nut and end cap if using carbine extension
Stock
Stripped upper receiver
Dust cover
Forward assist (unless the upper is “slick”)
Charging handle
Bolt carrier group
Grendel Type 2 bolt
Barrel
Gas block (correct diameter for barrel)
Gas tube (correct length for barrel)
Muzzle device (unless the barrel is not threaded)
Hand guard and barrel nut
Stripped lower receiver
Lower parts kit
Receiver extension (buffer tube)
Buffer
Buffer spring
Castle nut and end cap if using carbine extension
Stock
Stripped upper receiver
Dust cover
Forward assist (unless the upper is “slick”)
Charging handle
Bolt carrier group
Grendel Type 2 bolt
Barrel
Gas block (correct diameter for barrel)
Gas tube (correct length for barrel)
Muzzle device (unless the barrel is not threaded)
Hand guard and barrel nut
Hop on Youtube and watch any of the PLETHORA of AR-15 build videos, or take a gander at www.ar15.com forums. Tons of build threads there.
The only way this differs from a traditional .223/5.56 AR-15 is the bolt, barrel, and magazines.
if you switch calibers again you have to give me all your 6BR brass and the Team 6BR jersey back. If you go alltheway back to 6x47, I want $20...
Here’s another option
www.santantactical.com
SAN TAN TACTICAL® STT-15 6ARC RIFLE 6mm ARC Advanced Rifle Cartridge
SAN TAN TACTICAL® STT-15 6ARC RIFLE 6mm ARC Advanced Rifle Cartridge Chambered rifle
www.santantactical.com
I here mix reviews about santan rifles.Here’s another option
SAN TAN TACTICAL® STT-15 6ARC RIFLE 6mm ARC Advanced Rifle Cartridge
SAN TAN TACTICAL® STT-15 6ARC RIFLE 6mm ARC Advanced Rifle Cartridge Chambered rifle
who are the go to AR companies for accuracy ?
Well since it does “everything” better than the other AR15 options, how’s does it better 458 Socom on tough stuff up close? How does it better 300BO in a 9” suppressed config?
Actually does sound interesting but cartridges are usually a host of design compromises/restrictions. Wouldn’t quite get so carried away with the sales pitch. Some people can actually compare the goods and bads.
Nothings free.
Actually does sound interesting but cartridges are usually a host of design compromises/restrictions. Wouldn’t quite get so carried away with the sales pitch. Some people can actually compare the goods and bads.
Nothings free.
Well since it does “everything” better than the other AR15 options, how’s does it better 458 Socom on tough stuff up close? How does it better 300BO in a 9” suppressed config?
Actually does sound interesting but cartridges are usually a host of design compromises/restrictions. Wouldn’t quite get so carried away with the sales pitch. Some people can actually compare the goods and bads.
Nothings free.
And no one has advertised it as such.
You give up round count for speed and performance increase. Without needing to step up to AR10 platform.
That’s it. Nothing more, nothing less.
Try GA Precision also. They have barrels on order for builds but not sure if all spoken for or whom for.
I’m going to tell you that you need a 6.5Grendal barrel extension. The standard AR15 barrel extension the feed ramp bolt notches are too tight (not wide enough). Brady had issues with it beating up the bullet tips (accuracy was still excellent). Something to think about.
Picture attached of what we will say is the proper barrel extension.
Attachments
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yup, again good points... but ppc bolt face actions aren’t exactly easy to come by.
Give it a few weeks, they will start popping up for sure. There is also a bigger thread in the Semi-Auto section for the 6ARC you'll fine more info in.
Many people use our mag kits to run grendel and 224 valk... so I would suspect the 6ARC could be made to work as well. Just gotta get those feed lips tuned for the smaller cases is all.
Obviously the focus of the cartridge is semi-auto. I get that... but I also know people, and there will be a ton of them running this in bolt guns.
I can vouch for that. I've got one of the wildcats in an AR and I'm waiting on a Howa mini or CZ 5-whatever their tiny action is in this. maybe not the perfect comp cartridge but pretty flat shooting and funner than hell.
if you switch calibers again you have to give me all your 6BR brass and the Team 6BR jersey back. If you go alltheway back to 6x47, I want $20...
Yeah it drives me nuts because I miss 6x47's wind advantage but hated ordering barrels by 1300 rounds.
Frank, please offer at least 20 and 22" Carbon wrapped AR barrels when things get rolling for you on 6 ARC.
Interesting responses to my question.
When I resize my 260, I partial neck length resize, i.e., I use the F/L die, but adjust it upward so only roughly 1/2 to 2/3 of the neck gets resized. I also start with 7-08 brass and neck it down as below. The rear, unsized, (7mm dia) portion of the neck still chambers easily, remains expanded during firing, and does not get any potential work hardening.
This does a couple of things, I believe...
First, the rearward portion seats snug in the neck; which I think makes the forward portion and seated bullet more concentric in the chamber. When fired brass is examined, any soot stops precisely at the line where the neck diameter flares. I interpret this to mean the rearward portion of the neck is sealing completely.
This also reduces neck tension in a moderately controllable manner, i.e., more neck length resized = more neck tension, and vice-versa.
Eventually, shoulders need bumping. I use my 308 die (minus the decapping assembly) that's set up to reset shoulder length to the same size for both 308 and 260 cartridges, and both (Savage) 260 and 308 barrels are headspaced off the same field gauge, and checked against the same nogo gauge. This die relationship allows the web portion of the cases to remain expanded and reduces any work hardening in that portion of the case wall, except for when bumping the case. Remaining expanded, the rear prortion of the cartridge also tends to be more concentric in the chamber. Cartridges, 260 and 308, are checked for headspace on the same 308 case gauge, and the dies are maintained so the case base is just barely recessed in the gauge.
If there are donuts, I'd assume they would appear at the transition between the expanded and the resized portion of the case neck. I mic the neck thickness down to as far as the transition point, and am not encountering any obvious excess dimensional thickness indications. Not seeing pressure indications that would tend to indicate any pressure spikes. A bullet drops free into the case prior to resizing.
There's probably something I'm missing; but I'm calling it good, subject to the above monitoring.
Currently, I'm transitioning from conventional HPBT bullets to Speer Gold Dots (140's for the 260, 120's for the 6.5g). They have a different profile; being a rebated base like the older Lapuas. Their overall length is shorter, and appears to minimize/eliminate protrusion below the case neck, as well as charge compression.
Obviously, there is a sacrifice in BC; but I'll take the tradeoff in order to have a true hunting-capable bullet that far downrange. At a cost of around $.30 per bullet there's little to sniff at, either. Reviews indicate good accuracy, but I'm still in the load development stage.
Greg
When I resize my 260, I partial neck length resize, i.e., I use the F/L die, but adjust it upward so only roughly 1/2 to 2/3 of the neck gets resized. I also start with 7-08 brass and neck it down as below. The rear, unsized, (7mm dia) portion of the neck still chambers easily, remains expanded during firing, and does not get any potential work hardening.
This does a couple of things, I believe...
First, the rearward portion seats snug in the neck; which I think makes the forward portion and seated bullet more concentric in the chamber. When fired brass is examined, any soot stops precisely at the line where the neck diameter flares. I interpret this to mean the rearward portion of the neck is sealing completely.
This also reduces neck tension in a moderately controllable manner, i.e., more neck length resized = more neck tension, and vice-versa.
Eventually, shoulders need bumping. I use my 308 die (minus the decapping assembly) that's set up to reset shoulder length to the same size for both 308 and 260 cartridges, and both (Savage) 260 and 308 barrels are headspaced off the same field gauge, and checked against the same nogo gauge. This die relationship allows the web portion of the cases to remain expanded and reduces any work hardening in that portion of the case wall, except for when bumping the case. Remaining expanded, the rear prortion of the cartridge also tends to be more concentric in the chamber. Cartridges, 260 and 308, are checked for headspace on the same 308 case gauge, and the dies are maintained so the case base is just barely recessed in the gauge.
If there are donuts, I'd assume they would appear at the transition between the expanded and the resized portion of the case neck. I mic the neck thickness down to as far as the transition point, and am not encountering any obvious excess dimensional thickness indications. Not seeing pressure indications that would tend to indicate any pressure spikes. A bullet drops free into the case prior to resizing.
There's probably something I'm missing; but I'm calling it good, subject to the above monitoring.
Currently, I'm transitioning from conventional HPBT bullets to Speer Gold Dots (140's for the 260, 120's for the 6.5g). They have a different profile; being a rebated base like the older Lapuas. Their overall length is shorter, and appears to minimize/eliminate protrusion below the case neck, as well as charge compression.
Obviously, there is a sacrifice in BC; but I'll take the tradeoff in order to have a true hunting-capable bullet that far downrange. At a cost of around $.30 per bullet there's little to sniff at, either. Reviews indicate good accuracy, but I'm still in the load development stage.
Greg
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