Alternate Calibers: 6mm ARC vs 6.5 Grendel vs 6.8 SPC

[Themumfordman]

Curious about anyone’s experience - I’ve run 6mm ARC a bit and have a nice DMR type rifle now in 6.8, but I’ve never gotten trigger time on a 6.5 Grendel. Anyone know how it compares to the other 2, or even 6.5 Creedmoor (obviously a much heftier cartridge)?

 

[Little Jack]

I went the 6.5G route about the time the Wolf became available. I didn't have a specific need, it was just something else to play with. I've got a 20" odin barrel that's been consistently one ragged hole at 100yds with some hornady 123s. I put the Wolf through a couple of different 12.5" barrels. It's accurate enough but on the dirty side. I've shot way more of that because I was able to get a bunch pre COVID. I don't have the time/location to shoot them where I would potentially see any of the benefits of the round. ARC sounds cool but ammo cost/availability and my under 200yd shooting distances haven't made it worth trying out.

 

[Baddog 0302]

All depends on what you want to use them for and at what your range limit is ? Plus weather you reload or not.

 

[Themumfordman]

All depends on what you want to use them for and at what your range limit is ? Plus weather you reload or not.

Not reloading yet, but that's the goal. The idea for me is a mid-range caliber in an AR15 platform that gives better ballistics at 400-800 yards compared to 5.56 without going to a .308 or 6.5 CM.

 

[Baddog 0302]

OK, then I would suggest you look at some trajectory / bullet drop charts and see how they compare to what factory loads are available and at what velocities they are advertised at.
reloading , a 123 gn at 6.5 G velocities vs a 105 th 108 at 6 ARC

 

[joebagodonuts]

It's interesting to compare 6.5 Grendel to 5.56 and play around with barrel length/velocity. For example, my 16" 5.56 and my 18" Grendel are within .25 mil at 400 and 600 yards in regards to elevation. Wind favors the Grendel with a .10 mil advantage to the Grendel at those same distances. That's with the Grendel pushing 123 grain at 2500 fps and the 5.56 pushing 77 grain at 2700 fps. The 6.5 Creedmoor is shooting a 140 grain 2700 fps and it edges out the Grendel by .2 and .7 mil at 400 and 600 and wind deflection is also less by .1

All that to say, your results will vary and it depends on barrel length, bullet weight, etc. A lot of these testers are using 22 or 24” barrels and very few people use those in real life, especially in an AR platform

6.5 Grendel vs 6.5 Creedmoor: Which 6.5 Cartridge Is Right For You?

Want an accurate cartridge to use in an AR platform and can't decide between the 6.5 Grendel vs 6.5 Creedmoor? The best choice is

thebiggamehuntingblog.com

 

[Rebel_Rider1969]

Get a 300 blackout, lol. ( jk, seems to be the answer to everything)

 

[Bowhntr6pt]

I have all three.

On animals, hogs and coyote, they all perform very well. The Hornady 120gr SST for the 6.8 and the 123gr SST for the 6.5 are the only bullets I've put effort into and stuck with them vs. trying other bullets simply because the kill pretty effectively with proper shot placement.

I've also killed a lot of hogs and coyote with the 6mm ARC. It took about two-three years for ARC brass to become available so I bit the bullet and slowly acquired about 700 rounds factory ammo in order to harvest some brass. I'm still working through that stash so I've not played with the ARC at the loading bench.

There are strong followers of the 6.5G and 6.8SPC, both camps will claim one is better than the other citing various numbers and what not. I'm partial to the 6.8 SPC mainly because it was my first non-traditional chambering for the AR besides the big bores.

IMO for your intended uses I'd rank all of them (6.5, 6.8 6ARC) as equal out to 400-500 yards. Beyond that, I'd rank them 6mm ARC, 6.5G, and 6.8SPC for distance shooting on paper or steel.

Once 22 ARC brass becomes available, probably in two years, I plan to mess with that one as well.

In short, you can't really go wrong with either.

 

[sloporsche]

I have all three.

On animals, hogs and coyote, they all perform very well. The Hornady 120gr SST for the 6.8 and the 123gr SST for the 6.5 are the only bullets I've put effort into and stuck with them vs. trying other bullets simply because the kill pretty effectively with proper shot placement.

I've also killed a lot of hogs and coyote with the 6mm ARC. It took about two-three years for ARC brass to become available so I bit the bullet and slowly acquired about 700 rounds factory ammo in order to harvest some brass. I'm still working through that stash so I've not played with the ARC at the loading bench.

There are strong followers of the 6.5G and 6.8SPC, both camps will claim one is better than the other citing various numbers and what not. I'm partial to the 6.8 SPC mainly because it was my first non-traditional chambering for the AR besides the big bores.

IMO for your intended uses I'd rank all of them (6.5, 6.8 6ARC) as equal out to 400-500 yards. Beyond that, I'd rank them 6mm ARC, 6.5G, and 6.8SPC for distance shooting on paper or steel.

Once 22 ARC brass becomes available, probably in two years, I plan to mess with that one as well.

In short, you can't really go wrong with either.

how do they stack up against 243 win /270 win.

 

[Bodhisattva]

Curious about anyone’s experience - I’ve run 6mm ARC a bit and have a nice DMR type rifle now in 6.8, but I’ve never gotten trigger time on a 6.5 Grendel. Anyone know how it compares to the other 2, or even 6.5 Creedmoor (obviously a much heftier cartridge)?

What’s your objective?

 

[Bowhntr6pt]

how do they stack up against 243 win /270 win.

Kind of apples to oranges, obviously those cartridges have a little more juice.

 

[Themumfordman]

What’s your objective?

Decently precision DMR type rifle in a smaller size and power cartridge than a 6.5 CM or 308 using an AR15 platform setup. Shooting really in that 400-800 yard range, with the option of having something that’s a better potential hunting round than a 22 caliber 5.56.

 

[Bowhntr6pt]

Decently precision DMR type rifle in a smaller size and power cartridge than a 6.5 CM or 308 using an AR15 platform setup. Shooting really in that 400-800 yard range, with the option of having something that’s a better potential hunting round than a 22 caliber 5.56.

With that in mind I’d highly recommend the 6mm ARC now that ammo is easily obtained.

An 18” barrel with rifle length gas is what I’d go with for a balance between efficient powder burn and length/weight.

 

[Recondo 101]

Objective is use in the AR-15 platform, the twist rate is very important. Most companies wanting to throw heavier 6mm projectiles have gone to a 1-8 twist barrel and 18" to use powders more efficiently. The 24 GPC (24 Varmint) based on the 6.8 case the ARc (small c to indicate the 15) line based on the 7.62x39 case blown out with a 40 fegree shoulder and the 6m x 223 and the 6mm Mongoose with a blown out and shortened 223 case and 40 degree shoulder

These above cartridges can all be used in the AR-15 platform with a barrel change and mags and bolts made for the AR.

Now the 260, 243, etc. can be used in the 308 AR platform or the Armalite AR-10 platform, which is larger and heavier that the AR-15.

For a really light weight rifle with light recoil at .34" groups with 80s I like the 6 Mongoose for an after surgury rifle. But I am now working with the 24 Varmint currently to mount a thermal scope on with a bit higher velocity, to achieve a flatter trajectory for night shooting with a 90-95 for piggies. The 80 grain Rem does not have the penetration I want for hogs, works great for song dogs though.

 

[Mcnpeter]

20 inch 6mm arc. 100 yards. I thought i was really fucking up my shots until i inspected it. 3 round group.

if you go that route, i've got about 180 rounds of Hornady ammo ill deal you.

 

[Themumfordman]

Thanks all for the feedback. I’m looking at a couple 6mm rifles, or at least uppers at the moment. I may try to do some side by side testing of my own with the 6.8.

 

[SLTW]

6ARC all the way. The guy who won mammoth 2 years ago used a 6ARC. 6ARC will do what the 6.5G and 6.8 will do but with better ballistics and accuracy. The guy at mammoth made a 1200 yard shot with it.