New build.....caliber

[Mebe007]

So I have an aero m4e1 lower and sn aero upper sitting around. I just finished a 16" grendel, my first. I have another ar15 in 5.56 already. I'm debating building this into either a 20" grendel or a 20" 6mm arc. Would love to hear opinions ions. Not sure if it's worth diving into reloading for yet another caliber to reload

[Eye_guy]

“Better” ammo options and availability for the grendel. I’d take the Grendel for hunting, better ammo options, and more barrels commercially available. I’d take the ARC for better steel plinking capabilities.

Life is full of choices, neither would be wrong. Good luck and have fun!

[VASCAR2]

The only cost for me to get a 6 ARC would be dies and bullets. The 6.5 Grendel works well for me and the 6 ARC doesn’t give me much difference for how I shoot the last few years. I have held off getting a 6 ARC cause there is no factory marked 6 ARC brass. I don't want to resize 6.5 to 6 MM and have to sort brass.

I have a few 5.56/223 semi autos but don’t shoot them often. I think this will change as grandsons get older. I’ve looked hard at the 20” 6 ARC but the current politics in my state has turned things upside down for me.


You just have to weigh out how it will be used and which fits the roll the best.

[Mebe007]

The only cost for me to get a 6 ARC would be dies and bullets. The 6.5 Grendel works well for me and the 6 ARC doesn’t give me much difference for how I shoot the last few years. I have held off getting a 6 ARC cause there is no factory marked 6 ARC brass. I don't want to resize 6.5 to 6 MM and have to sort brass.

I have a few 5.56/223 semi autos but don’t shoot them often. I think this will change as grandsons get older. I’ve looked hard at the 20” 6 ARC but the current politics in my state has turned things upside down for me.


You just have to weigh out how it will be used and which fits the roll the best.

This is most on line whith how I feel at the moment. Not a ton of long range shooting here. Mostly deer hunting. The fact that 6arc brass is non existent and I would rely on factory ammo to build a brass supply is a major deterent. I don't really need anything as the stables are pretty full, but why have an unused upper and lower laying around lol *as well as a vg6 65 epsilon). Maybe a 20" grendel gets the nod to compliment the 16"

[Mebe007]

“Better” ammo options and availability for the grendel. I’d take the Grendel for hunting, better ammo options, and more barrels commercially available. I’d take the ARC for better steel plinking capabilities.

Life is full of choices, neither would be wrong. Good luck and have fun!

Again not much steel punching here in VA where I'm at. Now that being said I mostly deer hunt with occasional predator hunting. I guess I would feel more at ease jumping into the 6mm if things were more readily available. Don't seem like the grendel gives up much to the arc. So in reality does a 20" grendel serve a purpose over a 16"

[VASCAR2]

Barrel length has an effect on bullet velocity and elevation affects how fast velocity drops. The altitude you normally shoot might significantly affect ballistics to where one barrel length might prove to be the best for the elevation and terrain. Here are some velocities I got using a Magnettospeed Chronograph on a 70 degree day at 450’ ASL. If you use a G1 BC .510 for this factory ammo velocity with the height over bore (2.5” for 1” scope on AR-15, 2.75” for 30 mm scope on my AR-15’s) you can use a ballistic calculator to see which barrel might meet your desire.

I’m addicted to the 6.5 Grendel and have a 12” pistol, two 16”, one 18” and one 20” AR-15 plus a Cz 527 with 24” barrel. I like them all and enjoy shooting them. Each build is kind of specialized but I just enjoyed buying and assembling AR-15’s in 6.5 Grendel.


123 Grain SST Hornady

12” 2277

16" 2430

18" 2493

20" 2511

24" 2583

The forum has members who have used the 6.5 Grendel extensively in places all over the world. The 6 ARC and 6.5 Grendel are so close I give the 6 ARC the velocity advantage and is probably a better long range target cartridge. The 6 ARC might be a smidge better as a varmint cartridge in some situations. I give the edge to the 6.5 Grendel as a better game cartridge but it might be hard to physically see the difference in any hunting situation between the 6 ARC and 6.5 Grendel. Lack of ammo and brass has kept me from getting a 6 ARC as I have my bases covered by one of my 6.5 Grendels. I have shot to 1000 yards maybe 4 times in ten years. At my age who knows how many times I might get to shoot that far again. It really depends on how your going to most use your tool.

[SDguy]

So I have an aero m4e1 lower and sn aero upper sitting around. I just finished a 16" grendel, my first. I have another ar15 in 5.56 already. I'm debating building this into either a 20" grendel or a 20" 6mm arc. Would love to hear opinions ions. Not sure if it's worth diving into reloading for yet another caliber to reload

What is it you are wanting the rifle to do, or not do. Arc will offer lighter & Higher BC bullet offerings, in turn less recoil, more velocity & flatter shooting all else being equal & all will not be equal between two cartridges. 6.5 Grendel will offer More momentum & energy on target.

My personal experience will differ from your use in that I have used both cartridges in only bolt action rifles with 22" barrels. In this case my preference has been heavy for the 6mm ARC for many reasons. My use is target shooting geared towards deer hunting inside of 300 yards. ARC offers all I need on target with less recoil, A flatter bullet path & a wider bullet selection compatible for the cartridge, as a reloader.