6mm ARC - Practical Reloading

[Retired shooter]

Thank you .
After a brief read on the other site they claim CFE 223 as not being temp stable, so now who knows what to believe, I will continue to search for the Leverevolution.

Thanks again.

 

[Gtscotty]

Thank you .
After a brief read on the other site they claim CFE 223 as not being temp stable, so now who knows what to believe, I will continue to search for the Leverevolution.

Thanks again.

Sure, but neither are LVR and 2520. That's why Staball Match is exciting, if it gets close to matching LVR and CFE for speed in the ARC, it will be the first temp stable powder to do so.

 

[bucweet]

Hello to all that are still participating in this thread. I have a upper being built chambered in 6 ARC. Was going with 223 Valkrie till I got persuaded to try 6 ARC. From all the previous posts it looks like CFE 223 and Leverevolution have been the successful powders. I will be trying the 109 bergers first, looking to shoot past 1500 yards maybe a mile shot on steel. Has anyone tried AR comp powder, wondering how that has worked.

Anyone have a honey spot located to purchase brass..?

Thank you to all that have shared information and wisdom gained on the 6 ARC.
Looking forward to learning more about it.

I have an ARC in a 20" gas gun custom build for coyotes. I'm amazed at people trying to shoot so far with this cartridge, but go for it.
Lever works for me the best, I tried AR Comp, it was a little fast for bullets over 90 grains, it wasn't bad for 60 - 70 grain bullets.
As far as brass, most people get 6.5 grendel and reform. I just did some 220 Russian over the weekend and it works just as well.

 

[Retired shooter]

We shall see what happens.
Thank you.

 

[Dr. Jay]

I think you are over looking a very good powder for your 6 Grendel as I have tried both Varget and H4895 with no success and then I tried VV-N135, that was all it took to get my rifle to shoot.

 

[Retired shooter]

Hey Doc
I dont have the upper yet, it is still a work in process. I have been gathering all the necessities for reloading as it becomes available. Just priced one pounder sent to the house. I will have to wait maybe my local GS will get some Lever in . All I know is what I have been reading, on whatever forum I can find info. Have looked at my load books, and load data from Berger that is not in publication yet.
So still researching .

Thank you.

 

[MrK.]

I picked up a 20 inch CMMG upper from Midway a few weeks ago. Got my paws on a box of Hornady 103 grain ELD-X which cost about 40 bucks. Definitely the most I have spent on a 20 rd box of ammo but I wanted the brass. The Hornady loads were pretty disappointing only grouping about 1 1/2 inches at a hundred yards. I loaded up some test groups using Varget and 95 grain SSTs. I shot 4 groups a couple days ago and three of the four were inside an inch with the best being about .53 in the other two .74 and .83. Just 3 shot groups mind you. The fourth group which was Hornady's max load of 28.1 grains of powder started off good with the first two touching but the third was a crazy flyer that stretched the group out to almost 2 inches. There were zero pressure signs at that charge FWIW. I loaded up 6 to try and kill a deer with at the .74 inch load. It had a 10 fps SD and an average fps of 2680. I was hoping to bust 2700 but as a first load test I am pleased. I need more brass and am contemplating forming some from some once fired Alexander Arms (Lapua) 6.5 Grendel brass I have laying around. I formed a couple from Hornady Grendel brass but I could see I was starting to get the "belt" that some are getting with reformed Hornady. Wonder if the Lapua would be the same?? I want to experiment with some of the other powders I currently have on hand. Those I have in this general range besides Varget are: AA2015, IMR 3031, H335, TAC, IMR 4320 and H414. There is no current data for some of those powders so I must proceed with caution. I wonder if someone could formulate starting loads using 6mm PPC data taking into account pressure difference for gas guns? Seems Like the two rounds are damn similar. I am using a Lee 6mm PPC case trimmer with a few thousands filed off to trim my brass.

 

[SD guy]

If Velocity is a priority for you I expect you will wish to pick up at least 1 more propellant - LVR, CFE 223, Accurate 2520 & Powerpro 2000 MR would receive strong consideration if I was in your shoes. While I am a huge fan of this cartridge , my preference is my Bolt action CZ527.

The following article my be of intrest.

https://www.handloadermagazine.com/6mm-arc

 

[Retired shooter]

Thanks SDGuy
Yes still researching powders, really just looking for velocity, while maintaining safe pressures. Have Leverevolution on a reserved list local GS, they are good at letting me know when powder shows up.
Thinking I will have to experiment with some different primers.

Hey the journey is half the fun.

Have a great weekend.

 

[243Mendoza]

I think you are over looking a very good powder for your 6 Grendel as I have tried both Varget and H4895 with no success and then I tried VV-N135, that was all it took to get my rifle to shoot.

what load and bullet velocity are you getting with vv135? I suspect the load may be too high if you are using the heavy bullets

 

[Dr. Jay]

My 6 Grendel is built on a Rem 722 action with a 24 inch barrel . The load is 30gn. of VV-N135 and a 68 gn. Barts Dominator and .010 into the lands. Absolutely no signs of pressure overload and CCI-BR-4 . the velocity is 3362 fps.

 

[243Mendoza]

My 6 Grendel is built on a Rem 722 action with a 24 inch barrel . The load is 30gn. of VV-N135 and a 68 gn. Barts Dominator and .010 into the lands. Absolutely no signs of pressure overload and CCI-BR-4 . the velocity is 3362 fps.

Max loads on a bolt gun and a gas guns are different. Bolt guns can take more pressure. Also you are using lighter bullets; I was referring to 105-109gr class of bullets.

 

[Dr. Jay]

I kinda had the thought that you were referring to a gas gun and yes I know there is a differance between the two. I shoot short range benchrest and use 65gn or 68gn bullets.

 

[243Mendoza]

I kinda had the thought that you were referring to a gas gun and yes I know there is a differance between the two. I shoot short range benchrest and use 65gn or 68gn bullets.

The ARC was designed for a gas gun so I assumed that your loads was for a gas gun. I think that since safety is an issue for loading ammo, complete info should be included when any loads are given

 

[Rtheurer]

Doesnt the 5.56 Cartridge operate at pressures of around 60,000 psi in a M16/ AR15 platform, while a Bolt action in almost all modern cartridges 223 to 300 win mag are meant to operate at around 55,000 psi.

 

[243Mendoza]

Doesnt the 5.56 Cartridge operate at pressures of around 60,000 psi in a M16/ AR15 platform, while a Bolt action in almost all modern cartridges 223 to 300 win mag are meant to operate at around 55,000 psi.

SAAMI spec for the ARC is 52ksi;

 

[Rtheurer]

What does the AR platform capable of for pressure? Vs a Bolt action that is?

 

[Laurie]

What does the AR platform capable of for pressure? Vs a Bolt action that is?

As per SAAMI, ie 52,000 psi. Here's a view by White Oak Armament as to why 0.440" diameter case-head designs (ie as per the Grendel and ARC) aren't suitable in their view for the AR-15 bolt.

https://www.whiteoakarmament.com/blog/hornady-s-new-6mm-arc.html

Agree with White Oak or not, it's obvious that great care needs to be taken with handloads for these cartridges when loading for the AR-15 to avoid rapid bolt wear and/or failure.

This doesn't apply to bolt actions, hence the 62,000 psi Pmax allowance for this type. The case is extremely strong - the limitations come from bolt strength and designs.

 

[DocDoc]

The AR-15 was designed for the smaller diameter case. Increasing the diameter, as in the ARC, puts more force on the lugs (case has more area so more force on bolt). Something similar happens for bolt actions and Lapua size cartridges, you need bigger size with bigger lugs or there will be setback/failure.

 

[Laurie]

The AR-15 was designed for the smaller diameter case

Yes, just so. The AR-15 was designed for the 223 Rem (or to be pedantic, it was originally built around the 222 Rem) and its 0.378" diameter case-head. The 7.62X39 / Grendel / ARC 0.440" diameter rim has a 35% larger area bearing on the bolt-face.

IIRC, it's the internal case diameter and area that matters in bolt-face loadings, so the pair are shown as 0.378" (Grendel / ARC) and 0.332" for the 223 diameters in case drawings. That gives the fatter cartridges a just under 30% increase in load bearing area on the bolt.

None of this is helped by having to machine the lugs thinner to achieve the wider bolt-face, but those who understand these things (engineers) say it's the increase in cartridge base area and hence increased thrust onto the bolt that is what matters here. To keep the bolt-loading down to that specified for the smaller-diameter 223 Rem, the internal pressure has to be reduced ......... hence 52,000 psi for the larger cartridge.

SAAMI rates the parent cartridge, the 7.62X39mm as having an MAP of 45,000 psi, rather lower still. Even so, I remember reading somewhere that when the US Army carried out exhaustive testing of AR-15s in that chambering, bolts started to fail at around 10,000 rounds and that if adopted, a prophylactic bolt replacement would have to be instituted at the 9,000 rounds mark - a very unattractive option for the military on multiple counts.