6mm ARC: Has Hornady Struck Gold?

[Alpha-17]

Yeah, somehow I doubt that last part...

The margins for terminal performance are not that wide as you say and as distance increases, the margins narrow further. I can think of one exception of a wide variance in weight retention but it's with a company known for questionable data and it's a bullet that shouldn't be used for terminal effect in the first place.

The answer is push the better bullet. The first problem is always connecting to the target. A miss with a marginally terminally better projectile is a terminal effect of ZERO. And even with 308 bullet selection is critical and the better performing rounds are at the expense of external performance. If you're doing an apples-to-apples say in a TTSX Barnes, one still gets more forgiveness with their shooting solution. I'll happily take a better BC for the money any day.

Also what's the context?
We talking humane precision hunting/animal harvesting
Military?
LE?
(all rhetorical)

You seem to be quite certain that I'm intent on not learning anything. Odd. Was it the misspelling bit? That was a genuine mistake. I took a 5 year or so break from the shooting community, and don't recall people talking up Creedmoor like it was God's gift to riflemen back in 2015. Clearly I've missed something.

I've seen stats that show they have 40% of the weight retention when comparing bullet to bullet. Is that limited to a single brand? Or is that generally true across the board to one extent or another? Am I correct in understanding that within say, 500-600m there will be little to no improvement in getting a hit, while suffering from reduced terminal performance? That's the big one for me.

As for roles, pretty much all of those fit. What I look for in .308/7.62 NATO is a general-purpose cartridge that has power and moderate accuracy at range. Something that can be used for close-range use (if need be) then pushed out to the 5-600m usage. I don't see Creedmoor filling that role, personally, but rather is a niche round for long-range shooting. Again, if I am in error on this, please let me know.

[m4hk33]

As long as they use grendel bolts and mags, it's going to be an abortion

[pinzgauer]

Obviously I'm not the only one who feels this way, or we wouldn't have 6.5G, 6.8SPC, .224V, etc. I've settled on a .300BLK pistol with supers for close, 14.5" 5.56 for general use and 16" 6.8 for hunting or added punch. Yet I was still considering an unwanted AR-10 in 6.5CM or .243 to reach farther with a gas gun, knowing good and well it wouldn't make me completely happy.

I've been shooting grendel since 2007 or 2008. It's not perfect but it is awfully good at taking the AR-15 platform about as far as you can go with it.

Slippery projectiles in the weights that I want to shoot. Steel case ammo availability for fun. Inherently accurate due to some of the optimization that were made and its PPC parentage.

I keep and use 5.56, but Grendel is awfully good package / compromise for the AR-15.

As to AR-10s, everyone needs one just because. I've got a lot of West German surplus 7.62 and it's fun to take out to shoot. And I can shoot match loadings with good results as well.

I know 260 and creedmoor both will beat 308 at range but that's not an issue I have to deal with. (Wish I did have longer ranges, 300 is my local max)

[Furbyballer]

With guys like Jim Hodge and Monte at centurion arms behind this thing it may have some serious legs. Especially if Magpul steps in to address grendel magazines. Jim already publicly said hes looking at offering a 12.5, 14.5 and 16in CHF 6mm arc barrels.

[pinzgauer]

As long as they use grendel bolts and mags, it's going to be an abortion

You say this from personal experience?

My brother and I have bought and use close to 50 Grendel magazines over more than a decade from different sources in different lots have never had an issue in several rifles. CSC or Elander, all have worked.

Same for bolts.

Nor do I know anyone in my extended circle of friends who shoot Grendel that has had issues.

I believe the grendel mag/bolt thing is currently an internet myth that started based on some very very early issues with the very first Grendel magazines.

Any cartridge with a larger base diameter is going to put more pressure on the bolt. So yes Grendel is pushing the ar-15 bolt boundary in that regard. But a properly made Grendel bolt will last. It is pickier about heat treat and metallurgy, and some early Grendel bolts got out that were not heat treated correctly according to Bill Alexander. So there was an issue early 2000s.

Hornady's not stupid, it begs the question why didn't they make this on the 6.8 case? If there were ongoing issues they would have picked a different case format.

[rainman]

DISCLAIMER: I'm quite excited about this cartridge.

Serious conundrum here that I'm trying to reconcile.

Several years ago there seemed to be two camps; 6.5 Grendel and 6.8 SPC. From what I remember, 6.5 G had much better long range ballistics, but the mil (a small group within the mil community) seemed to like 6.8 SPC better for wound ballistics from 0-to-600 yds (or so). I seem to recall that experiments had been done with projectiles from 6.5-to-7.0 mm, and that 6.8 mm was the compromise arrived at that would work within the limitations (mainly bolt and magazine length) of the M4 platform.

Now it seems that the mil (or an (different?) elite group within the mil community) is using a smaller version of the 6.5G cartridge they once rejected in favor of the 6.8 SPC that never really caught on in the US mil.

I wonder what has changed (projectiles, powder, research/accrued results) to make 6mm ARC (essentially a smaller version of 6.5 G) a viable cartridge for limited mil use? Genuinely interested in hearing from Constructor and other SMEs on this. Please correct anything I have said with regard to what I've stated regarding 6.5 G vs 6.8 SPC history.


-Rainman

[Todd.K]

The 6.5G was never part of the SPC project. Bullets from 6mm to 7mm were tested as I recall, .270 being the best compromise for terminal performance with OTM and reasonable trajectory. I'm not convinced the 6.8 would be a .270 caliber if bonded or all copper bullets were part of the mix. But it was designed for military use with the best approved bullet of the time.

I think some target shooters will find this useful, people into the latest thing will become long range trajectory experts to justify it (without actually needing it), hunters will stick with the 6.5 or 6.8 they already have, and the next really measurable step comes when a truly intermediate sized gun/magazine is developed.

[Clint]

What caliber do you think it might have been?

6.5mm?

6mm ?

The 6.5G was never part of the SPC project. Bullets from 6mm to 7mm were tested as I recall, .270 being the best compromise for terminal performance with OTM and reasonable trajectory. I'm not convinced the 6.8 would be a .270 caliber if bonded or all copper bullets were part of the mix. But it was designed for military use with the best approved bullet of the time.

I think some target shooters will find this useful, people into the latest thing will become long range trajectory experts to justify it (without actually needing it), hunters will stick with the 6.5 or 6.8 they already have, and the next really measurable step comes when a truly intermediate sized gun/magazine is developed.

[FromMyColdDeadHand]

What is the cheapest blaster ammo for this caliber?

[rainman]

The 6.5G was never part of the SPC project. Bullets from 6mm to 7mm were tested as I recall, .270 being the best compromise for terminal performance with OTM and reasonable trajectory. I'm not convinced the 6.8 would be a .270 caliber if bonded or all copper bullets were part of the mix. But it was designed for military use with the best approved bullet of the time.

I think some target shooters will find this useful, people into the latest thing will become long range trajectory experts to justify it (without actually needing it), hunters will stick with the 6.5 or 6.8 they already have, and the next really measurable step comes when a truly intermediate sized gun/magazine is developed.

Many thanks for the correction and information. The matter of an "intermediate sized gun/mag" is something that seems to be inevitable.


-Rainman