6mm arc bolt gun?

[LotI]

I've played with my Savage 110 18" for a bit. Accuracy is just ok. 105 Hornady BTHP with CFE223 just under max reached 2731fps but accuracy fell apart up there. 28.1gr Varget was a 1/2" group @2677fps. Ballistic calculators show it supersonic at 1200 yards.

Factory 108ELDM was well over 1" on several groups @2605fps.

I've had great results with 70gr. Speer TNT that I had a bunch of from years past.

I bit the bullet and during a Memorial day sale bought a 26" barrel to swap. Now I'm just waiting for it to be built. It's strange that 6mm projectiles cost quite a bit less than 6.5mm, not much more than .224".

I've converted range pick-up 7.62x39 and 6.5 Grendel brass with little drama. 6.5G is as easy as running it through the 6ARC die but 7.62x39 needed the intermediate step of going through a 6.5G die to eliminate crushed shoulders. Case capacity of 6.5G seems similar but 7.62x39 is a bunch smaller. I formed them with some 55gr Noslers and Varmint powder.

 

[Rtheurer]

7.62x39 Brass has a large primer and does not handle pressure real well. The loads i tried would open the primer pockets up in just a two loadings after working all the time to neck it down. If I had no other brass available i certainly would give it a try.
I was kinda dispointed when my Lapua 7.62x39 brass was toast after two firings. But i had to try. PPU was the same way.

 

[uncle fester]

I've played with my Savage 110 18" for a bit. Accuracy is just ok. 105 Hornady BTHP with CFE223 just under max reached 2731fps but accuracy fell apart up there. 28.1gr Varget was a 1/2" group @2677fps. Ballistic calculators show it supersonic at 1200 yards.

Factory 108ELDM was well over 1" on several groups @2605fps.

I've had great results with 70gr. Speer TNT that I had a bunch of from years past.

I bit the bullet and during a Memorial day sale bought a 26" barrel to swap. Now I'm just waiting for it to be built. It's strange that 6mm projectiles cost quite a bit less than 6.5mm, not much more than .224".

I've converted range pick-up 7.62x39 and 6.5 Grendel brass with little drama. 6.5G is as easy as running it through the 6ARC die but 7.62x39 needed the intermediate step of going through a 6.5G die to eliminate crushed shoulders. Case capacity of 6.5G seems similar but 7.62x39 is a bunch smaller. I formed them with some 55gr Noslers and Varmint powder.

One of the reasons I got a 6 ARC Savage was the relatively low cost of bullets vs my 6.5CM.

 

[LotI]

Just an update to my ARC project. The X-Caliber barrel came in. 26” Palma contour, 1:7.5” 5R 416SS, threaded 5/8”. Took about 8 weeks to be built and PTG took about 4 to get me a go-gauge.

Beautifully done, a look with the Teslon shows very good finish and crown. Threads are perfect but my Savage receiver isn’t. I’ve got tools on the way to clean it up. Their barrel nut is nice too. My factory recoil lug doesn’t fit over the barrel either so I have a EAB machined piece on the way to replace the stamped factory crap.

I have two Savage Elite Precision rifles with the MDT ACC chassis so they will be loaning them to the 6ARC for now. The factory stock would need a lot of work to get this fatty to fit.

I’ve measured distance to lands so I loaded up some Hornady 105BTHP, 108 ELDM, and Berger 108’s to get started. CFE223 I have in bulk but also a pound of LeverEvolution.

I also emailed Hornady asking about 6mm ARC brass availability and here’s their response…

”Unfortunately, we're not sure right now. Most of the brass we're making is being used to load ammunition in house. We are in the process of expanding our case plant and expect production to improve later this year.”

 

[SD guy]

Lots:

Look forward to hearing how you Like this build as you get out shooting this build. Not sure if you have looked though It feels like the Whidden click adj bushing dies may interest you.

Click Adj. Bushing FL Die Set + Bushing Kit - Whidden Gunworks

Take advantage of this discounted bundle of our Click Adjustable Bushing FL Die Set and Bushing Kit in the caliber of your choice.

www.whiddengunworks.com

Note: on acquiring brass. Forming 6mm ARC brass from 6mm Grendel is a fairly straight forward process. Lightly wax your brass to be formed From 6.5 mm Grendel to 6mm ARC. Proceed with 1 pass to neck down & push shoulder back. I purchased the Whidden Head space gauge & really like this. I am finding consistent .002 Head space clearance is quite easy to achieve & control.

Case Gauge - Whidden Gunworks

Use the chart below to reference the other compatible calibers for each gauge. If you don’t see the Case Gauge you need, we can custom build you one with your supplied Go Gauge. Select the "Custom" option in the drop down menu and follow the instructions. Attention: The Belted Magnum Family...

www.whiddengunworks.com

Trim to length & chamfer inside & out & you are ready to start load work up.

Take your pick on Grendel brass from what may be available. Thus far I have Worked with Lapua & Starline & while I have a strong preference for the Lapua, Starline 6.5 Grendel brass has been fairly good to be honest.

 

[jkirk]

Spent last evening trying to find the perfect bullet for my 1:7 6 mm ARC bolt gun to shoot out to 1000 yards. I ran the ballistics various bullets from the 103 ELDX to the 115 DTAC with a bunch of different weights in between. I used velocities that were reasonable for a bolt gun (i.e., not the top-hot loads). Much to my surprise, they all came out about the same. There were no clear winners. I thought for sure the heavy weights would win at that range, but that was not the case. Next step after that discovery is to search for the most accurate (and maybe cheapest?) bullet to load. I'll now have a lot of possible choices.

 

[revoman]

I debated the AR vs Bolt gun for my 6mm ARC build. I came to the conclusion there are many superior cartridge options for a bolt rifle, with many fewer customizations (aka custom milled bolt head). So if I wanted to shoot 6mm ARC I should build an AR.
I haven't regretted that decision and love my 6mm ARC AR.

 

[LotI]

SD guy,

I’ve been reloading 6ARC for about a year so I’m set on equipment and brass. I have about 100 Hornady 6ARC brass, 50 6.5G, and over 200 7.62x39 ready. For a refresher the barrel is a X-Caliber 26” stainless 1:7.5” 5R barrel threaded 5/8-24.

I got out last week to shoot and had great luck with 105 Bergers, and 105 Hornady BTHP. Several groups in the 4’s. All were loaded to the lands so seating depth testing will come next. It didn’t shoot Hornady 108 ELDM’s as well as the “lesser“ BTHP. From prior experience they like a little jump.

Velocities we’re impressive around 75fps faster than Hornady’s data and their 24” barrel. All shots were shot suppressed. Factory 108ELDM ammo shot a 0.75” group and velocity was right at what they publish, 2748fps with an SD of 9 fps.

Pressure signs started showing up well under max published data. All were loaded with CFE223 in Hornady brass and BR4’s. SD’s were 9-12fps for most loads but a couple jumped up.

108 ELDM velocity
27.8gr. 2587fps
28.8gr. 2681
29.2gr. 2733
29.7gr. 2783 bolt a little sticky and slight ejector marks
30.1gr. 2828, only shot 2 because of pressure signs.

105BTHP velocity
27.3 2561
28.2 2669
29.1 2769
29.6 2818 started having sticky bolt lift.

I only shot 1 load with the Berger BTHP at 29.2gr and 2734 fps. No load data but based on the data I‘LL treat them like a 108ELDM.

The picture shows the groups and data. Chrono data is shown next to each trial and the measurements shown are the group size. The H-L-A-E-S is from the chrono…high, low, average, extreme spread, and SD. The first number is horizontal, 2nd vertical, 3rd is largest spread, in thousanths. Then I average them, like the AMU does But round to the hundredth. The red stickers are 1”.

 

[David Milisock]

Spent last evening trying to find the perfect bullet for my 1:7 6 mm ARC bolt gun to shoot out to 1000 yards. I ran the ballistics various bullets from the 103 ELDX to the 115 DTAC with a bunch of different weights in between. I used velocities that were reasonable for a bolt gun (i.e., not the top-hot loads). Much to my surprise, they all came out about the same. There were no clear winners. I thought for sure the heavy weights would win at that range, but that was not the case. Next step after that discovery is to search for the most accurate (and maybe cheapest?) bullet to load. I'll now have a lot of possible choices.

I was shooting 6MM for nearly 40 years and I've never seen much anything different than you have. My best heavy for accuracy is the 105 Hornady match. My bolt rifle and my AR love them. The Hornady interlock and the 103 ELDX are decent game bulletts.

 

[David Milisock]

I debated the AR vs Bolt gun for my 6mm ARC build. I came to the conclusion there are many superior cartridge options for a bolt rifle, with many fewer customizations (aka custom milled bolt head). So if I wanted to shoot 6mm ARC I should build an AR.
I haven't regretted that decision and love my 6mm ARC AR.

My choice many years ago was the 6MM Remington it is a good bolt rifle for deer and varmint round.

My youth was spent running around a regulated game farm in a Jeep with an M1 Carbine. About a year ago I upgraded with a 16" AR15 M4E in 6MM ARC about the same size as my M1 Carbines bit vastly improved accuracy and abilities out past 600 yards.

 

[moorepower]

I've played with my Savage 110 18" for a bit. Accuracy is just ok. 105 Hornady BTHP with CFE223 just under max reached 2731fps but accuracy fell apart up there. 28.1gr Varget was a 1/2" group @2677fps. Ballistic calculators show it supersonic at 1200 yards.

Factory 108ELDM was well over 1" on several groups @2605fps.

I've had great results with 70gr. Speer TNT that I had a bunch of from years past.

I bit the bullet and during a Memorial day sale bought a 26" barrel to swap. Now I'm just waiting for it to be built. It's strange that 6mm projectiles cost quite a bit less than 6.5mm, not much more than .224".

I've converted range pick-up 7.62x39 and 6.5 Grendel brass with little drama. 6.5G is as easy as running it through the 6ARC die but 7.62x39 needed the intermediate step of going through a 6.5G die to eliminate crushed shoulders. Case capacity of 6.5G seems similar but 7.62x39 is a bunch smaller. I formed them with some 55gr Noslers and Varmint powder.

Wait, 1/2" groups is "OK" for a factory rifle? Kind of busting your chops, because I get that you want to shoot other bullets in it. My 22" AR likes Hunter, N140 and or all things Leverevolution the best. I'm going with a Shilen select match from Northland