20” 6ARC bullet selection…

black5.3

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Im in the process of assembling a 20” 6mm ARC upper and wanting to narrow down bullet selection and powder options for the uses this upper will see. It will be ran suppressed 100% of the time.

At first it will be scoped and do some load development/plinking. Probably later this year it will get a thermal scope and more than likely remain that way.

Im looking at a lighter bullet for speed and varmint hunting. Maybe something in the 70-80 grain class. I currently have Varget that should be suitable for what im trying to do but ooen to other powder options i should look in to.

Thanks for the helps gents. Also this will be a PVA Osprey barrel so im looking to get some rounds down it and see how it shoot.
 
Sharing the twist rate and any idea you have of the freebore dimensions would be useful.

There are some known decent predator/varmint bullets in 6mm, but the weight range will be dictated by the twist.

For example, the Berger 80 Varmint FB has a very forgiving tangent ogive that works well in many barrels.
Hornady covers the whole span from 65 grains on up.
Sierra has a new 90 TGK and also some from 55 grains on up.

The advice can be narrowed down by saying your twist rate.
 
There’s a ton of load data here.
I can push 58 gr VMAX 3500 fps with Lever and 18” Proof 1:7.5tw. 87 VMAX 2950.
 
Sharing the twist rate and any idea you have of the freebore dimensions would be useful.

There are some known decent predator/varmint bullets in 6mm, but the weight range will be dictated by the twist.

For example, the Berger 80 Varmint FB has a very forgiving tangent ogive that works well in many barrels.
Hornady covers the whole span from 65 grains on up.
Sierra has a new 90 TGK and also some from 55 grains on up.

The advice can be narrowed down by saying your twist rate.
The twist rate is 1:7 according to PVA’s website.
 
A 1:7 is a fast twist bbl in 6mm and meant for being able to shoot the longest/heaviest bullets.

For example if you give it a Berger 109 LRH it would still have an SG above 1.78 and anything lighter is going to have an even higher SG.

If you try to go real light with thin skinned varmint bullets, you might be risking spinning the bullet RPM high enough to see some come apart.

I would consider the same bullet Hornady loads in 6 ARC, which is the 80 ELD-VT.
With a 200 yard zero, you are holding fur to 300 yards.

Merry Christmas and Happy New Year!
 
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The 6 ARC is kind of a strange cartridge. It is spec'd as a 1 in 7.5 twist but it is designed as a fairly low pressure (52KSI) round for the AR15 platform and is designed around a 108 Gr round at 2700 fps. Hornady has published higher pressure loads (62KSI) for bolt action rifles which would probably work well with the heavier 6 mm bullets. I think the 70-90 gr bullets is where I would start unless I'm relaying trying to stretch this guy out beyond 800 yds.
 
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I have a 20" Proof AR, rifle +1 gas, 8tw IIRC. I reloaded a batch of Hornady 80 gr ELD-VT using 30.7 gr of CFE223 (30.9 was Hornady max data) and obtained 2930 fps, suppressed. Accuracy was better than factory, but I need to get a stiffer forend at some point. They are my point & shoot coyote load.
 
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I definitely think bullets in the 80gr-90gr class will do what im trying to. I picked up a pound of Leverevolution to try and i have varget on hand but i may grab a pound if benchmark or cfe223 to try…. Maybe one day i can find xbr8202 again.
 
I definitely think bullets in the 80gr-90gr class will do what im trying to. I picked up a pound of Leverevolution to try and i have varget on hand but i may grab a pound if benchmark or cfe223 to try…. Maybe one day i can find xbr8202 again.
Yes, it is always a little bit of prognostication when it comes to guessing about which companies will make which powders and when wars and embargoes will interfere with our lives. I would take the best of what is available and roll without waiting for indefinite powders to come back. Life is too short.

I still advise rookies to run one of the known best extruded for when it counts, and also run ball powders to save effort on bulk. Sometimes, those ball powders do so well you are surprised.

Some of us were shooting Rat and FatRat with 107 grains (or less) over a decade ago in our ARs. In case you weren't around then, those were wildcats based on the Grendel case, and the Grendel case and ARC case might as well be twins.

The main point of bringing up the ancient past, is to tell you to relax and enjoy the process. These were very easy designs to play with and there were no bad tendencies compared to alternatives. The 6 ARC will run exactly down the paths beaten down by those old Grendel based wildcats, which was an easy story. In for the range reports.

Merry Christmas, Happy Hannukah and Happy New Year!!!
 
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Nothing is going to compare to Lever performance wise with anything but perhaps the lightest if 6mm bullets. I recently loaded up some 75g vmax for coyote, will probably pick up some 80g eld-vt.

Lever is incredibly dirty suppressed or unsuppressed. Bcg can just add oil but the chamber and barrel needs attention more often. Works great when pushed at the top, great groups and SD, little temp sensitive but predictable, and no pressure spikes if you loaded a little warm for hot days.

I've been experimenting with Benchmark for 75g vmax and 95g Berger targets. Can't achieve as much velocity as Lever but it runs exponentially more clean. Varget, LT32, and XBR8202 didn't produce the speed I want with varget being the worst. 8208 wasn't bad but it spikes when you get near the top. Might revisit in the summer
 
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Yes, it is always a little bit of prognostication when it comes to guessing about which companies will make which powders and when wars and embargoes will interfere with our lives. I would take the best of what is available and roll without waiting for indefinite powders to come back. Life is too short.

I still advise rookies to run one of the known best extruded for when it counts, and also run ball powders to save effort on bulk. Sometimes, those ball powders do so well you are surprised.

Some of us were shooting Rat and FatRat with 107 grains (or less) over a decade ago in our ARs. In case you weren't around then, those were wildcats based on the Grendel case, and the Grendel case and ARC case might as well be twins.

The main point of bringing up the ancient past, is to tell you to relax and enjoy the process. These were very easy designs to play with and there were no bad tendencies compared to alternatives. The 6 ARC will run exactly down the paths beaten down by those old Grendel based wildcats, which was an easy story. In for the range reports.

Merry Christmas, Happy Hannukah and Happy New Year!!!
Thanks for the advice! I wouldn’t consider myself an expert by any means but I have been in the reloading scene for about 11ish years now and have seen the good times and the bad times go by during different administrations and various events in the news. I learned a while back to stock up in the good times because the next hard times are just around the corner. Thanks again for the help and I hope you and your family had a Merry Christmas.
 
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Nothing is going to compare to Lever performance wise with anything but perhaps the lightest if 6mm bullets. I recently loaded up some 75g vmax for coyote, will probably pick up some 80g eld-vt.

Lever is incredibly dirty suppressed or unsuppressed. Bcg can just add oil but the chamber and barrel needs attention more often. Works great when pushed at the top, great groups and SD, little temp sensitive but predictable, and no pressure spikes if you loaded a little warm for hot days.

I've been experimenting with Benchmark for 75g vmax and 95g Berger targets. Can't achieve as much velocity as Lever but it runs exponentially more clean. Varget, LT32, and XBR8202 didn't produce the speed I want with varget being the worst. 8208 wasn't bad but it spikes when you get near the top. Might revisit in the summer
Thanks for the help. I have some 87gr Vmaxs on hand now and some 80gr eld-vt’s on the way. I may just skip trying Varget all together and save it for my other cartridges that I already use it for.