What are the differences?

[Tugaloo]

Spot on!!

As both the Hornady 6mm ARC and the 6.5 Grendel uppers work on the AR-15 or M16 or any either's variations. Why was the 6mm ARC selected?? The 6mm ARC uses (based on) the 6.5 Grendel's case with some changes.

I can find an article that offers some, but very little information.
https://www.firearmsnews.com/editori...6mm-arc/376909

The 6mm ARC is based on the 6.5 Grendel. Hornady started by necking down the cartridge to 6mm and then pulled the shoulder back closer to the case head .030-inch. Engineers also shortened the case to make the cartridge friendly to long low-drag bullets that have high ballistic coefficients. The 6mm ARC was designed around optimal use with a 108-grain bullet.

https://www.gunsandammo.com/editoria...6mm-arc/376852

All I can say is that's nice.. ROFL

.

[Armyjimbo]

As a 6.5 Grendel shooter, I'd need to see one and try it before I would drop money on it. The bonus to Grendel is its neck thickness is such that I can swage a 7.62x39 down and not have any issues other than trimming to length. I set a WORLDS FINEST TRIMMER in my drill press and they get done quickly and easily. My last brass purchase was 3000 pieces, 1/2ish I converted then annealed with a induction machine I put together myself based on this.

[Tugaloo]

I agree and add, I'd have to spend some time at the controls to see what it offers that I need. A lot of new calibers end up being a want rather than a need.
I have a rule about adding new calibers to the safe.
However, there is a way to find an exception. I have a .22 mag pistol; so adding a .22 mag rifle would be OK.
I've been burnt with new calibers. I bought a AR in 6.8 SPC as it was a top contender for being adopted by the military which would lead to less expensive FMJ. Plus, it adds more effective range over the 5.56. Guess what, it wasn't adopted.

However, a Wylde chamber upper is a very good upgrade to an AR lower. The negative is its .2240 free bore adds more distance before engaging the rifling. OTOH, I noticed it doesn't affect accuracy. Actually, it increases the accuracy of 5.56 NATO ammo.

https://www.shootingillustrated.com/...ar-15-chamber/

https://www.ammunitiontogo.com/lodge/what-is-223-wylde/

Induction annealing is the way to go. As a Ham radio operator, I have wound coils for antennas and it isn't that difficult.
BTW, as you're the first person I know of who built their own induction annealing coil. Kudos!!!!!

[Armyjimbo]

I decided to add one to my reloading equipment, after I decided to attempt the 1km milk jug challenge. 10 shots max, 1km to hit a milk jug. it's approx 10x10 " so it's a 1 MOA shot.. To achieve this I want my brass to be as even as possible, then weigh the bullets also to minimize variances there. Powder is always weighed, after that it's all up to the weather gods.

[Tugaloo]

I decided to add one to my reloading equipment, after I decided to attempt the 1km milk jug challenge. 10 shots max, 1km to hit a milk jug. it's approx 10x10 " so it's a 1 MOA shot.. To achieve this I want my brass to be as even as possible, then weigh the bullets also to minimize variances there. Powder is always weighed, after that it's all up to the weather gods.

The induction annealing method is a lot easier than the "torch", water and rotate method.

I also sort by case volumes, primer depth and flash hole diameter etc. Anything to get everything as close to even as possible.

Not that you didn't know that, but just to keep a conversation going on a very slow board.
Or helping the "guests" with reloading.
Hey guests, why not register and join the group?

[Armyjimbo]

I'm trying to find my 9mm tool head for the Dillion 550 semi processive press I own, using it I get about 200 rounds done in 1/2 hour. Once I find that darned toolhead, the press is sold. I'm upgrading to a 1050 model that can be motor driven and will require zero effort to run hundreds at a time. The press has multiple spaces on it allowing swaging of primer pockets at one site and trim to length at another. BUT Ihave to find the missing toolhead.....
Yup going high tech, If I wanted to I could run it for a few days, then relax for a year.

[Tugaloo]

Let get real! Just how many shots will you take over 250-309 yards away? Not many. Most combat is close no more then 75 yards. Look at the after action reports from the last 20 years. Long distance needs a sniper equipment, training and weapon system.....

Hunting I will never use a light weight round!!!

I used to hunt varmints, specifically ground hogs in western MD, Due to the foothills of the Appalachian mountains, often shots over +200 yards were available. Due to the .222 Rmag's drift, a windless days were required. Unlike today, twists in the 1/9, 1/8 and 1/7 were not available; as a result, stabilizing a heavy bullet was not possible.

With a 7mm Rmag, I used to hunt deer on power line clear cuts using a 139 gr to 140 gr bullet. I'd shoot from hill top to the next hill top even the side of the next hill. Beats me if it was legal or not and if it was time limits expired decades ago. As a HS kid and later a college kid, I didn't know a mil-dot scope existed.
As I lacked all today's fancy equipment; how was it possible? Before deer season, I'd scout the clear cuts for deer trails and fire ranging shots.

During Russia's war in Afghanistan, the Muj would scoot and scoot using the .303 well out of the AK's range. Before the Russian using a Drag could reply; the Muj scooted.
The US issued M14s with optics as a counter.

The US military bases its plans for the next war on the last last war. The 7.62 NATO replaced the .30 CAL because more 7.62 NATO fit into a conex container than .30 CAL. In addition, cyclic rates increased. Or so said a lot of authors who never spent any time in combat.
General LeMay was the driving force behind the M16 and 5.56 which was adequate for Vietnam's shorter ranges.

[Armyjimbo]

Let get real! Just how many shots will you take over 250-309 yards away? Not many. Most combat is close no more then 75 yards. Look at the after action reports from the last 20 years. Long distance needs a sniper equipment, training and weapon system.....

Hunting I will never use a light weight round!!!

. My club has 500m steels, and after not much practice thats the distance I commonly plink at. Thats with all but my .223 Rem and .22lr. I do stretch my .22lr out to 150m and my .223lr to 300. No fancy tools just maths, if you know your velocity and bullet drop longer shots are easy. I am a (was a) sniper and no tools/aids are required for these ranges, yes it makes it easier but it's not required. Practice is always a good thing.

[Tugaloo]

Was your issued optic mil dot MOA or mil dot (AKA MRAD) radian?