New tech and advancements are here. Whats the new best AR15 cartridge?

[Yondering]

Well I can't argue with any of that except to say my fanboi for the 6.8 ends just past 500 yards. After that I become a 6.5 CM fanboi. And much past 1200'ish I'm totally open to suggestions.

OK, I guess that's reasonable enough to an extent, and I certainly respect knowing the limitations of your equipment.

But why make up all that other stuff about cartridges you know nothing about? You have to know at some level that it makes you look bad and is a detriment to the forum. It just smacks of the classic "Chevy vs Ford" arguments, which really boil down to immaturity and arguing to defend your own choice rather than looking at what's actually best.

Regarding that 500 yard limitation on the 6.8, that's probably about right depending on the load, but I wonder if you're aware that you can basically double that range with either a 6 ARC or 224 Valkyrie? (The trajectory and wind drift are really close between those two with the right bullet and powder choices.) You've commented that you think the AR15 is limited to shorter range, but you're confounding the limitations of your cartridge choice with limitations of the platform.

I own or have owned most of the rounds listed in the OP except the 300 Hamr and 22 Nosler, plus a number of other AR15 rounds that aren't covered here. (With the caveat that my 6mm rifles are an earlier Grendel wildcat rather than the official ARC, but performance and other details are nearly identical other than that .030" shorter shoulder.) Talking about good loads/bullets in each of course, in my experience the 224 V, 6mm, and 6.5mm Grendel are significantly easier to hit with than the 5.56 or 6.8 out past 500-600 yards or so, especially if there are unpredictable winds like when shooting across a canyon. The 6.5 Grendel has a lot of drop to account for, but the 224 and 6mm really stretch out the AR15's capability. My long 6mm in particular feels like cheating at 9000-1,000 yards and beyond, and even the short 12.5" 6mm SBR is easier to hit with in the wind at 600 than my best 16" 5.56.

As for the 6.5 Creed, I like and use that as well, but it's using about 50% more powder, more recoil, and is a fair bit trickier to tune right in a gas gun, and trickier to shoot well in a gas gun too than the small frame stuff. Regardless, if you're trying to make consistent 1,000 yard hits on steel or whatever, there are several good options in the small frame AR15 without needing to step up to the Creedmoor in a large frame or bolt gun.

 

[Yondering]

2.45" or 2.5 mags would be good with me

square out the receiver to where the notch is in mags.. sharpen the shoulder to 40 degrees

You can get to 2.355" or so just by cutting the front out of ASC stainless mags. I do that for 5.56 in a particular rifle to use the 70 and 77 gr RDF. But in the short fat Grendel-based cases, there's generally enough room in an unmodified mag that it's not needed.

 

[91Eunozs]

I voted 6.8 SPC, but what I shoot is a 6.8 SPC-II.

The ‘dash 2’ has higher pressures, and better terminal performance than the plain vanilla SAAMI spec round. Also to consider, the new .277/6.8mm (6.8x51 I think) round Uncle Sugar is going with may change the game for all of us, so this caliber …not the cartridge, as that’s more similar to an AR10 or SCAR17 than the AR15… may be the best for everyone in the next decade or so as US .gov supply chains switch over to that caliber vs. .223/5.56.

—

Long version of how I came to this result: I own more than a dozen ARs with at least two uppers for each, usually a 5.56 and then some other flavor in an upper that also matches the look/frame for that lower. I’ve built several for friends and family, but don’t personally own a single regular ‘black gun‘ AR; closest is a tan 16” with Magpul furniture or maybe my black 9” PDW. Four of my lowers are SBR’d, and yes, I have a couple ‘pistols’ too just to play with some of the uppers with the ability to more easily cross state lines.

Bottom line is I’ve shot the AR platform in almost every configuration possible; mostly just punching holes in paper, but several for pigs or coyotes, as well as the occasional deer or other high fence game here in TX. All have their place…horses for courses.

I count the AR10 and SCAR 17 in that mix too, but that’s definitely a different conversation, let alone rifles like the Petra, etc. in 300 Win Mag or other magnum calibers.

—

Results: If you can have only one rifle with only one upper? No question, the 5.56 every time. Many arguments listed so far, but the biggest being commonality of parts and ammo. This answer will likely change 10 years from now.

Add only one more upper? 300BLK for me…again, every time. I reload and shoot more of this round than all my others combined. It’s just a super easy round to tune to my needs and love shooting subs suppressed. My hearing’s shot from flying jets and working on airfield ramps most of my adult life, and trying to save what little remains. And I literally have thousands of once, twice, etc. fired 300BLK brass that I’m constantly cycling through the inventory.

If the 300 HAMR would have come to market sooner, or if I was just starting out, I’d likely pick that round over the 300BLK…better in every measurable way except availability and price.

These choices aside, for dedicated pig hunts, I always grab the 6.8 SPC-II. This is the best feral hog round that I’ve personally used; great balance between terminal performance and felt recoil, and it’s very flexible when it comes to barrel length…works great in 12.5” as well as 16+” barrels. You may give up some longer range performance with the shorter barrels, but it just flat works. Better performance past 100 yards than anything in my collection unless we step up to .308 or heavier.

I also considered the 6.5 Grendel (another fantastic round) but picked the 6.8 due to ammo and bullet availability.

If I know it’ll be in heavy brush, I sometimes grab my 450 Bushmaster upper. The Thumper’s pretty awesome within 50 yards or so, but very limited magazine capacity and the recoil make it a lot less fun for casual shooting. I personally believe the .458 SOCOM is a better round in this category, but I reload and shoot a ton of .45 ACP, and the simplified logistics of just buying one bullet type for both pistol and rifle makes it easier for my needs in this niche.

edit: also built a 350 Legend upper last year, but I’m still new to this round…I think it has a lot of promise for a higher capacity and quieter thumper type cartridge inside 50 or maybe 100 yards. I’m slowly cycling through factory ammo and some of my virgin brass to development a load something like my 300BLK subs, but maybe even quieter with better terminal performance at very short range. Still a wildcat in my mind though.

—

So end result from my perspective? Shoot what you want!

Beauty of the AR platform is having the ability to swap to an entirely different rifle for an entirely different need/mission with just the push of two pins, and maybe a magazine swap. Roll with it!

 

[TonyTheTiger]

Also to consider, the new .277/6.8mm (6.8x51 I think) round Uncle Sugar is going with may change the game for all of us, so this caliber may be the best for everyone in the next decade or so as US .gov supply chains switch over to that caliber vs. .223/5.56.

Except that it isn't an AR15 cartridge, so while it is ballitically interesting, it means nothing in this context of a conversation about AR15 cartridges.

 

[91Eunozs]

Except that it isn't an AR15 cartridge, so while it is ballitically interesting, it means nothing in this context of a conversation about AR15 cartridges.

Correct. I was thinking bullets, and maybe new powders for reloading

 

[TonyTheTiger]

Correct. I was thinking bullets, and maybe new powders for reloading

Maybe. I wouldn't be surprised to see all the latest greatest 6.8x51 bullets being too heavy for the SPC in the same way that all the new bullets designed to maximize 6.5CM are too heavy for Grendel. I'm not really arguing with you, just postulating for conversations sake.

 

[91Eunozs]

Maybe. I wouldn't be surprised to see all the latest greatest 6.8x51 bullets being to heavy for the SPC in the same way that all the new bullets designed to maximize 6.5CM are too heavy for Grendel. I'm not really arguing with you, just postulating for conversations sake.

No worries…we’re on the same page, and great callout actually.

Will edit my original post to better emphasize the ‘caliber’ vs. ‘round’ distinction.

 

[91Eunozs]

Maybe. I wouldn't be surprised to see all the latest greatest 6.8x51 bullets being too heavy for the SPC in the same way that all the new bullets designed to maximize 6.5CM are too heavy for Grendel. I'm not really arguing with you, just postulating for conversations sake.

also to consider, some of these newer and hopefully ballistically superior bullets may be able to be used with different twist rate barrels on the older platforms. I‘ve shot everything from 90gr up to 140gr bullets through my 6.8, and have landed on 110s as my preferred weight for the pig hunts I do here.

Will be very interesting to see what bullets and barrel twist rates the new cartridge likes at the 80K+ Chamber pressures they’re using. I’m pretty sure they’ll find (likely have already found) the upper limits of bonded or sheathed bullets; probably solid copper bullets, but I’m curious about terminal performance losses there.

Getting off topic though… LoL

Still voting .223/5.56 and a secondary 300BLK upper, with a preference for 6.8 … for now!

 

[Ndbowhunter]

You can get to 2.355" or so just by cutting the front out of ASC stainless mags. I do that for 5.56 in a particular rifle to use the 70 and 77 gr RDF. But in the short fat Grendel-based cases, there's generally enough room in an unmodified mag that it's not needed.

2.38 is about as short as you can go with 75gr eld-m and not have ogive inside of case mouth if you file down the red top slightly. you can actually flatten it down even more, but down range performance is very similar to 77gr tmk. bc is about .43 or so.

you can window the back of mags as well. numbers aren't in the head but it's 2.42 or so that h end up with. mag ended up looking like a m1 garand enbloc but works fine with steel mags.

best option tho would be to square out the mag and slightly hog out metal towards trigger group and run a true mid size action in the platform instead of weakening the bolt face by opening it up to run shorter/fatter cases.

 

[WindstormSCR]

Except that it isn't an AR15 cartridge, so while it is ballitically interesting, it means nothing in this context of a conversation about AR15 cartridges.

I wouldn't say it means nothing, the bimetal case tech and use of new alloys to handle higher chamber pressures while retaining existing form factors has some potential for improving on existing AR cartridges, giving small frames power and ability that was previously the sole domain of large frame sizes.

one example that has already been theorized is a revised 6mm ARC that gets very close to 6mm Creed levels of performance from a standard AR platform

 

[TonyTheTiger]

I wouldn't say it means nothing, the bimetal case tech and use of new alloys to handle higher chamber pressures while retaining existing form factors has some potential for improving on existing AR cartridges, giving small frames power and ability that was previously the sole domain of large frame sizes.

one example that has already been theorized is a revised 6mm ARC that gets very close to 6mm Creed levels of performance from a standard AR platform

I suppose that might be possible, and very interesting if it pans out. That said, the thought of a small frame that recoils more than a large frame and has shorter barrel life that may require expensive brass may not be as appealing in reality as it is in theory.

 

[Mocadon]

OK, I guess that's reasonable enough to an extent, and I certainly respect knowing the limitations of your equipment.

But why make up all that other stuff about cartridges you know nothing about? You have to know at some level that it makes you look bad and is a detriment to the forum. It just smacks of the classic "Chevy vs Ford" arguments, which really boil down to immaturity and arguing to defend your own choice rather than looking at what's actually best.

Regarding that 500 yard limitation on the 6.8, that's probably about right depending on the load, but I wonder if you're aware that you can basically double that range with either a 6 ARC or 224 Valkyrie? (The trajectory and wind drift are really close between those two with the right bullet and powder choices.) You've commented that you think the AR15 is limited to shorter range, but you're confounding the limitations of your cartridge choice with limitations of the platform.

I own or have owned most of the rounds listed in the OP except the 300 Hamr and 22 Nosler, plus a number of other AR15 rounds that aren't covered here. (With the caveat that my 6mm rifles are an earlier Grendel wildcat rather than the official ARC, but performance and other details are nearly identical other than that .030" shorter shoulder.) Talking about good loads/bullets in each of course, in my experience the 224 V, 6mm, and 6.5mm Grendel are significantly easier to hit with than the 5.56 or 6.8 out past 500-600 yards or so, especially if there are unpredictable winds like when shooting across a canyon. The 6.5 Grendel has a lot of drop to account for, but the 224 and 6mm really stretch out the AR15's capability. My long 6mm in particular feels like cheating at 9000-1,000 yards and beyond, and even the short 12.5" 6mm SBR is easier to hit with in the wind at 600 than my best 16" 5.56.

As for the 6.5 Creed, I like and use that as well, but it's using about 50% more powder, more recoil, and is a fair bit trickier to tune right in a gas gun, and trickier to shoot well in a gas gun too than the small frame stuff. Regardless, if you're trying to make consistent 1,000 yard hits on steel or whatever, there are several good options in the small frame AR15 without needing to step up to the Creedmoor in a large frame or bolt gun.

I know, and I don't have much experience beyond 6.5 CM and 308 in the larger frames. I've been struggling with reloading the 6.5 CM with StaBall and I guess I wish we lived in a world where I could just buy jugs of H4350 at every Circle K. I was in the shifting wind yesterday at both 600 and 1000 and my groups were more like random horizontal splatter. Grrr.

 

[WindstormSCR]

I suppose that might be possible, and very interesting if it pans out. That said, the thought of a small frame that recoils more than a large frame and has shorter barrel life that may require expensive brass may not be as appealing in reality as it is in theory.

The jury is out but so far commentary from several folks seem to indicate the alloys also provide reasonable barrel life (I think @Frank Green had something to say in that regard??) and recoil should be managable with other tuning (weight, gas regulation, etc)

brass might be expensive, but you could likely get away with neck sizing only for an increased lifespan

 

[TonyTheTiger]

The jury is out but so far commentary from several folks seem to indicate the alloys also provide reasonable barrel life (I think @Frank Green had something to say in that regard??) and recoil should be managable with other tuning (weight, gas regulation, etc)

brass might be expensive, but you could likely get away with neck sizing only for an increased lifespan

I wouldn't consider myself a master handloader, but I've never seen or heard of neck sizing only being viable for semi auto function.

Reducing recoil in semi autos is a bit of a hobby of mine, and it can certainly be done with large frames, but I've yet to see anyone beat physics and negate the recoil effects of doubling powder charge and/or bullet weight. Not saying a large frame is going to be completely uncontrollable, but I'll swerve out of my civilian, non operator lane and guess that for the type of fighting that AR's or average infantrymen are asked to do, speed wins more fights than ballistic horsepower, and a large frame heavier recoiling rifle will lose in the speed department. I could be wrong, again, I'm no body stacking badass. But I've tried to tune 6mm and 6.5 Grendel and 300BO to keep up with a 5.56 AR in speed and controllability and it can't be done, so I don't see a large frame doing it.

 

[WindstormSCR]

I wouldn't consider myself a master handloader, but I've never seen or heard of neck sizing only being viable for semi auto function.

The primary issue for neck sizing only in semis is expansion of the cartridge base (hence the common use of small base sizing dies) but with the cartridge base being stainless steel that ceases to be an issue, so as long as you’re shooting it from the same rifle it shouldn’t matter.

as far as recoil. I doubt this would be for military use (at least at first) but more of interest for those who want the weight benefits of a small frame without giving up performance. So my expectation would be initially strictly civilian until the market got the issues worked out. Its doubtful that you’d approach 5.56 levels of recoil, but you would certainly improve other cartridges with relatively minor increases in recoil

 

[Biggy]

Geissele should have their 6mm ARC rifles out in the next 1-2 months. They are using a barrel extension and mags that are specifically made for the 6mm ARC cartridge. It will be interesting to see how the new 6mm ARC shakes out in the AR15 platform in the next 1-2 years.

www.gunsandammo.com › editorial › hornady-6mm-arcU.S. Military Adopts Hornady's New Cartridge: 6mm ARC - Guns ...

New Sniper Support Rifle & New Advanced Rifle Cartridge

 

[357Max]

Dude, that is true for ALL small cartridges. Every single cartridge discussed here shares that same attribute.

That’s true. From what I’ve tried Lever is the hands down winner for ARC & Valk. I’ll take that velocity & deal with the temp sensitivity.

The only exception I can think of is 8208 for the 223. It doesn’t appear to be a great fit for the ARC. Maybe lighter wt in the Valk? I was actually thinking of trying some XBR with 60 Vmax’s in the Valk.

 

[montigre]

For my short to mid range do anything rifle, I still prefer 223/5.56...There's tons of the stuff out there, so very little worry for shortage and it gets the job done without beating you up (like the old Mausers). For specialty work, then the cartridge chosen is specific for that use. For me, it's 6.5 CM.

 

[RUTGERS95]

LOL. Or you can't articulate whatever you actually meant.
I read what you wrote, I can't read your mind.

you clearly cannot read. I suggest you take your trailer park education back to the kiddie table and continue reading 'see spot run'

 

[TonyTheTiger]

It will be interesting to see how the new 6mm ARC shakes out in the AR15 platform in the next 1-2 years.

You do realize that 6 ARC has basically existed for over a decade right? There's not really much to shake out, just more money to be made off of people that just recently became aware of it.

 

[RUTGERS95]

For my short to mid range do anything rifle, I still prefer 223/5.56...There's tons of the stuff out there, so very little worry for shortage and it gets the job done without beating you up (like the old Mausers). For specialty work, then the cartridge chosen is specific for that use. For me, it's 6.5 CM.

agree and I'll say it as it's got 4 variables that together means nothing beats it for 'performance', 'cost', 'weight', and 'application'. I could add controllability at high rates of fire for a 5th variable.

inside of 300 meters, it's absolutely top candidate

 

[knuckleballz]

The 6mm hagar case has the most powder volume of any case I know of that runs in an ar15 magazine. Necked down to .224(220 thunderbolt)allows you to run 77 grain bullets at 3200fps without any pressure signs. Guys are getting 3500fps with 55 grain bullets. This uses the same bolt and magazines as the 6.8spc/valkerie, and is much better than the 22 nosler. Padom has posted some great information on this cartridge.

 

[Evlshnngns]

The 6mm hagar case has the most powder volume of any case I know of that runs in an ar15 magazine. Knecked down to .224(220 thunderbolt)allows you to run 77 grain bullets at 3200fps without any pressure signs. Guys are getting 3500fps with 55 grain bullets. This uses the same bolt and magazines as the 6.8spc/valkerie, and is much better than the 22 nosler. Padom has posted some great information on this cartridge.

Tougher bolt than a grendel/arc, little more capacity in the mag. With quality bullets a 22 nosgar could do a lot of damage. Nosler should sell 22 nosgar brass, they are idiots for not doing it.

 

[thedarkknight]

I don't know who made the chart but it is clearly biased in favor of the 6mm ARC. If you get rid of cartridges like the 300BLK subsonic, 450 BM and 350 Legend that skew the averages of recoil and bullet drop and don't belong in this conversation and then used data from the same barrel length for all of the cartridges. I feel like the results would be much more balanced.

None of these newer cartridges are head and shoulders above the rest in my opinion. I'd also be willing to bet you could find a similar chart from a few years ago that "showed" how great the 22 Nosler and 224 Valkyrie compared to the others before 6mm ARC came on the scene.

Chart sourced from here https://www.shootingillustrated.com/content/the-complete-guide-to-ar-15-cartridges/

 

[Rocketvapor]

The 22 Nosgar, shortened from the 6mm Hagar/Thunderbolt holds less powder than a 22 Nolser but is a stronger case.
The 6.8 sized rim doesn't take much metal out of the bolt face over the 5.56 sized bolt of the 22N.
Body Die to resize (slowly), Modified Lee Collet .223 Neck Die, Trim, Use 22N barrel, 6.8 bolt.
I consider the 22N (Nosgar) the big brother of the 224V for long load slow fire

 

[RUTGERS95]

The 6mm hagar case has the most powder volume of any case I know of that runs in an ar15 magazine. Necked down to .224(220 thunderbolt)allows you to run 77 grain bullets at 3200fps without any pressure signs. Guys are getting 3500fps with 55 grain bullets. This uses the same bolt and magazines as the 6.8spc/valkerie, and is much better than the 22 nosler. Padom has posted some great information on this cartridge.

Interesting

 

[TonyTheTiger]

Chart sourced from here https://www.shootingillustrated.com/content/the-complete-guide-to-ar-15-cartridges/

That wasn't the worst article, even if it appears Captain Obvious wrote it. The part were he said 6ARC, 224V etc. may be ideal for 3 gun proves that he's writing from a position of theory more so than practice however.

 

[Rocketvapor]

6mm HAGAR necked down holds more powder than the 22 Nosler or 22 NOSGAR.

 

[Yondering]

You do realize that 6 ARC has basically existed for over a decade right? There's not really much to shake out, just more money to be made off of people that just recently became aware of it.

Agreed. For those of us who've been shooting some form of 6mm Grendel for years now, it's been both amusing and frustrating to see the flood of new adopters who all have something to say about it but know next to nothing, and are "waiting to see if it works".

Imagine if we had something called the internet, where information about something like this was freely available to anyone wanting to search for it...

 

[Yondering]

The 6mm hagar case has the most powder volume of any case I know of that runs in an ar15 magazine. Necked down to .224(220 thunderbolt)allows you to run 77 grain bullets at 3200fps without any pressure signs. Guys are getting 3500fps with 55 grain bullets. This uses the same bolt and magazines as the 6.8spc/valkerie, and is much better than the 22 nosler. Padom has posted some great information on this cartridge.

Powder volume doesn't help much when you can't fit longer bullets.
If the goal is to run the same bullets as 5.56 at higher velocity, it'll do that. If the goal is to greatly extend the range of your AR15 rifle, there are better options.

Single loading and giving up semi auto capability is a poor solution other than a limited niche for competition.

 

[Rocketvapor]

That's why you need more than one.
The best for this and one for the best for that.
The niche for competition.


I didn't expect anyone to agree.

 

[Frank Green]

I know, and I don't have much experience beyond 6.5 CM and 308 in the larger frames. I've been struggling with reloading the 6.5 CM with StaBall and I guess I wish we lived in a world where I could just buy jugs of H4350 at every Circle K. I was in the shifting wind yesterday at both 600 and 1000 and my groups were more like random horizontal splatter. Grrr.

What's your load with Staball?

 

[Frank Green]

The jury is out but so far commentary from several folks seem to indicate the alloys also provide reasonable barrel life (I think @Frank Green had something to say in that regard??) and recoil should be managable with other tuning (weight, gas regulation, etc)

brass might be expensive, but you could likely get away with neck sizing only for an increased lifespan

What's your question?

Later, Frank
Bartlein Barrels

 

[Mocadon]

What's your load with Staball?

I've been trying a few with 140 & 147 ELD-M's. The one that's working best is the 140 with 43.7 of StaBall loaded to a COAL of 2.800. But not great ES or SD. But it groups best. Later this week I'm going to reconfirm that's the case. I also need to try some new brass, probably will grab some more Hornady just cause that's what's available. Semi autos are hard on brass.

 

[WindstormSCR]

What's your question?

Later, Frank
Bartlein Barrels

there was a previous thread about the 6.8x51 that sig was playing with, and I thought you mentioned something about new alloys and durability, I couldn't find the exact exchange so I thought it better to summon you and see if you had any commentary on the rounds high pressure/velocity causing fast or premature throat erosion with the new alloys (if you're allowed to say anything at all)

 

[Paradox]

We all have 223/5.56 and it's been around long enough. Even the military wants a new cartridge. There have been many advances and discoveries is tech, powders, aerodynamics, etc. If cost and availability were not an issue, what do you think should be the next cartridge standardized for the masses? https://www.shootingillustrated.com/content/the-complete-guide-to-ar-15-cartridges/

Supposedly theyre about to settle on some plastic cased 6.8mm (all new) not related to any other 6.8. Odd round and the fun submissions are plain bizarre and honestly what good did all the extra ammo that coud be carried do?
Let everyone runaround full auto amd not hitting jack shit. It averaged out to 50,000 rounds of 5.56 to kill vietcong. That’s scary especially snd they only used 40-45000 per kill in ww2 by all the allies combined. Bigger is better, all the cops with 9mm laughed at tbose of us with 45s and 357s. But its quality, your odds of walking away from a 357 or 45 to the chest are almost zero, while the 115 grain silver tip remains one of the worst all time rounds to in one shooting a suspect vehicle took 10 to the windshield with only two getting through giving the susexf two little burn marks on his chest and where recovered off the seat.

 

[Paradox]

5.56 has been proven? At what? Being useless?
A 22 is a 22 at the days end. It was one stupid fucks brainstorm that more rounds were better, and that’s a big myth. Velocity only goes so far to make up for tiny bullets, the short barrels finished it off and they kept going shorter killing it more all the way down to the asinine 10.3 “ mk18 and the band aide 75 gr and buffer mods just so it will cycle. You cant even hand load a 223 to any great effect. And while some of the odd rounds out there promise they still miss the boat because not a one does it all. 224 has crazy range, 300 aac is quiet and hit hard from short barrels etc. but none will ever be a do it all 308, 243, 260, 7mm-08 and so forth. What short of magic is going to allow a 22 to outperform a 175 gr 308? A 1911 in 45 or 38
Super and an M1A in QCB stock and you’re solid, think about it, you design a gun with such. Shitty charging design that you need a forward assist to get the bolt closed just by thinking abiut dirt. I dont know a single person that hasnt used it at least a dozen times over the years. If the AK47 was actually built with advanced machining, and ditched the 762/39 and made it accurate it would be the world perfect military rifle.

 

[Frank Green]

I've been trying a few with 140 & 147 ELD-M's. The one that's working best is the 140 with 43.7 of StaBall loaded to a COAL of 2.800. But not great ES or SD. But it groups best. Later this week I'm going to reconfirm that's the case. I also need to try some new brass, probably will grab some more Hornady just cause that's what's available. Semi autos are hard on brass.

Your powder charge seems like your in the right area. One of the ammo makers is using Staball with his 6.5CM on a bolt gun we built him with our barrel. 135Atips at like 2900fps. Gun is shooting .5moa with SD around 5.5.

I've never loaded Staball in my guns. I've been lucky to keep getting my hands on H4350. Just recently been loading some Shooters World Powder and that seems to be working pretty good as well.

Who made your barrel is one question I have for you. Might not like the load and or bullets etc...also if it's a semi....your follow thru etc...has to be good. Can't be sloppy with your hold etc...vs a bolt gun. You can get away with a little more with the bolt gun vs. the AR10 type rifles.

What twist is your barrel? If it's a button rifled barrel the twist might not be true and or uniform. This will make it temperamental as well.

Later, Frank

 

[Frank Green]

there was a previous thread about the 6.8x51 that sig was playing with, and I thought you mentioned something about new alloys and durability, I couldn't find the exact exchange so I thought it better to summon you and see if you had any commentary on the rounds high pressure/velocity causing fast or premature throat erosion with the new alloys (if you're allowed to say anything at all)

The round was working pretty good in our new BB material.

Standard 416R and standard c.m. barrels that hot round chews them up like water. I'm going to keep the round count to myself for now from what I was getting on the barrel life on the ammunition test barrels. It was the first round of testing that I got data back on and it was in standard material. More testing is in process and I haven't heard of any new numbers yet.

The other thing I've heard is the steel case head/brass body is hard on the chambers as well. The steel doesn't expand/shrink back like the brass does.

 

[WindstormSCR]

The round was working pretty good in our new BB material.

Standard 416R and standard c.m. barrels that hot round chews them up like water. I'm going to keep the round count to myself for now from what I was getting on the barrel life on the ammunition test barrels. It was the first round of testing that I got data back on and it was in standard material. More testing is in process and I haven't heard of any new numbers yet.

The other thing I've heard is the steel case head/brass body is hard on the chambers as well. The steel doesn't expand/shrink back like the brass does.

Thanks, curious to hear more when you’re allowed/want to say more. Definitely lines up with what I expected though.

 

[Frank Green]

Supposedly theyre about to settle on some plastic cased 6.8mm (all new) not related to any other 6.8.

I'm not sure about that with the 6.8 and the plastic cases. Pretty sure it's going to be a steel case head and a brass body. Pretty sure it's a two piece case.

Kind of like these two piece cases in the attached picture. Steel case head with an aluminum body. Interesting thing I heard on these was that after firing you didn't have to resize the case. You could reload it right away due to the aluminum contracting back to size is how I understood it.

The attached picture was a 40cal rifle we made the barrels for testing etc...used the two piece cases. Barrel was like 40" long in that picture if I recall correctly. This was at Shot Show two years ago. Right before pandemic hit.

Later, Frank

 

[Paradox]

I'm not sure about that with the 6.8 and the plastic cases. Pretty sure it's going to be a steel case head and a brass body. Pretty sure it's a two piece case.

Kind of like these two piece cases in the attached picture. Steel and aluminum case heads with an aluminum body.

The attached picture was a 40cal rifle we made the barrels for testing etc...used the two piece cases. Barrel was like 40" long in that picture if I recall correctly. This was at Shot Show two years ago. Right before pandemic hit.

Later, Frank

I got the info from this article, but just seams like more government nightmares and after seeing this entry by General Dynamics, they need to stick with aircraft the links are below and interesting read if nothing else. it looks like they're trying to do another on gun fits all like when hey had the idea the M14 would double as a Full Auto Squad weapon, a 3 year old would know that would never work.

Actually the photos of he rounds appear to be plastic coated brass, with mention of all polymer, so i think youre' probably correct.

this thing here is one of the entries to supposed replace the M4, and the belt fed M249. In the end it always takes a regular individual to fix the convoluted minds of the mechanical engineer, now i thing highly of the abilities some of them have, but the moniker of "Educated Asshole" really does make sense when you see stuff like this or the 26000 pound Oshkosh truck that's supposed to replace the Humvee. lol

This Exotic Bullpup Rifle Is Competing To Replace The Army's M4 Carbines And M249 SAWs

This is the only entry in the Army's competition to use a bullpup configuration and it has other unique features, such as a recoiling barrel assembly.

www.thedrive.com

Ammo Firm Unveils 6.8mm Cartridge for Army’s Next-Gen Squad Weapon

A Texas-based ammunition company recently unveiled its new 6.8mm cartridge.

www.military.com

 

[Frank Green]

I got the info from this article, but just seams like more government nightmares and after seeing this entry by General Dynamics, they need to stick with aircraft the links are below and interesting read if nothing else. it looks like they're trying to do another on gun fits all like when hey had the idea the M14 would double as a Full Auto Squad weapon, a 3 year old would know that would never work.

Actually the photos of he rounds appear to be plastic coated brass, with mention of all polymer, so i think youre' probably correct.

this thing here is one of the entries to supposed replace the M4, and the belt fed M249. In the end it always takes a regular individual to fix the convoluted minds of the mechanical engineer, now i thing highly of the abilities some of them have, but the moniker of "Educated Asshole" really does make sense when you see stuff like this or the 26000 pound Oshkosh truck that's supposed to replace the Humvee. lol

This Exotic Bullpup Rifle Is Competing To Replace The Army's M4 Carbines And M249 SAWs

This is the only entry in the Army's competition to use a bullpup configuration and it has other unique features, such as a recoiling barrel assembly.

www.thedrive.com

Ammo Firm Unveils 6.8mm Cartridge for Army’s Next-Gen Squad Weapon

A Texas-based ammunition company recently unveiled its new 6.8mm cartridge.

www.military.com

They are one of the companies that submitted or are submitting a rifle and ammunition.

The round is a caseless ammo type round. Pretty sure it's not a polymer around a brass case body. I could be wrong.

 

[Mocadon]

Your powder charge seems like your in the right area. One of the ammo makers is using Staball with his 6.5CM on a bolt gun we built him with our barrel. 135Atips at like 2900fps. Gun is shooting .5moa with SD around 5.5.

I've never loaded Staball in my guns. I've been lucky to keep getting my hands on H4350. Just recently been loading some Shooters World Powder and that seems to be working pretty good as well.

Who made your barrel is one question I have for you. Might not like the load and or bullets etc...also if it's a semi....your follow thru etc...has to be good. Can't be sloppy with your hold etc...vs a bolt gun. You can get away with a little more with the bolt gun vs. the AR10 type rifles.

What twist is your barrel? If it's a button rifled barrel the twist might not be true and or uniform. This will make it temperamental as well.

Later, Frank

Good info, thanks Frank. I need to really focus on doing my part and see what I can get the gun to do with various COAL's at 100. I'm sure the barrel is shooting sub MOA based on sub MOA verticals at 1,000 and some good groups at 100 & 200, but I can't be more specific than that. With weather rapidly improving I should be able to get comfortable behind the scope and we'll see. It's the Adams Arms factory nitrided 4150 barrel and I've thought about swapping it out. But, it's a DPMS G2 format so hard to find. Craddock would be like $1,000 for a Bartlein.

I've got some loads to test so we'll see.

 

[WindstormSCR]

They are one of the companies that submitted or are submitting a rifle and ammunition.

The round is a caseless ammo type round. Pretty sure it's not a polymer around a brass case body. I could be wrong.

TV is a steel case head but full polymer body, I've done some experiments with the .308 commercially available stuff they sell, it's interesting but not really commercially compelling.

Basically while you *can* reload it, it's difficult and doesn't give as consistent a result as regular brass, and while the weight savings can be significant, the cost outstrips that and semi-autos beat it up pretty good.

if I were competition shooting with a large frame semi I'd be interested if it was sponsor money paying for it and not my own pocket, lets put it that way.

 

[HenryRed]

I've been trying a few with 140 & 147 ELD-M's. The one that's working best is the 140 with 43.7 of StaBall loaded to a COAL of 2.800. But not great ES or SD. But it groups best. Later this week I'm going to reconfirm that's the case. I also need to try some new brass, probably will grab some more Hornady just cause that's what's available. Semi autos are hard on brass.

Avoid the 147. Applied ballistics found consistentence issue them. Follow them on Facebook.

 

[Mocadon]

Avoid the 147. Applied ballistics found consistentence issue them. Follow them on Facebook.

I'll check that out. Thanks.

 

[Constructor]

6mm ARC vs 5.56 / .223

0-300-500 yds (12.5" inch -18-20" barrels) = 5.56/ .223 (30rd mags) = Okay
0- 600 - 800 yds+ ? ( 12.5" inch - 18-20" barrels) = 6mm ARC (25 rd mags) - Better penetration through barriers ? = *Overall* better ??
How does barrel life compare between the two ?

6mm at same speed but not on the Grendel case. If they wanted to design and build a new rifle like the LWRC SIX8 with a mag well wide enough to use pmags and allow the cartridges to stack correctly and use a bigger bolt then yes that would be a good performing round.

 

[Constructor]

I'm sure it's plenty reliable for the average civilians use, but shortly after it came out LWRCI and Magpul teamed up to make a proprietary intermediate frame rifle and magazines to "optimize reliability" if that tells you anything.
View attachment 7859089

Yeah is says Jordan told LWRC if they wanted the contract they (Jordan)wanted magpul pmags and Federal to produce the ammo. The 6.8 came out around 2003 and LWRC didn't sell it to Jordan and some other country over there until around 2010. With metal mags It works much better than the Grendel.

 

[Vynz]

This is a tough question. I’ve owned and used 300Blk, 458SOCOM, 6.5Grendel, and 6ARC. Can’t say I’d want to stock any of them over just having more 556 ammunition and more AR15s in 556. These cartridges were all fun and interesting for a while but once that ended I just buy ammo when I have the itch to shoot them.

300Blk was at peak fun running around with a 9" Silenced SBR shooting subs at targets 100yards and in. Mentally it was cool to have more power than 9mm and the option to use supers for even more range. Practically the paper targets were never deader compared to when I used a 9mm SBR, it was not more quiet, and the extra range of supers meant messing with zero on a red dot or prism when switching ammunition.

458SOCOM was also super fun running around with a silenced 12" SBR at targets 100yards an in. Again mentally it is cool to max out mass and therefore energy in a subsonic load, I even like how the extra recoil made its feel big and powerful. Practically speaking, making it a 5lb rifle probably wasn’t a great idea - it’s a total recoil and noise party even with a silencer.

Between the two I kept the 458 purely for fun as it maximized an experience unique from 556 while 300Blk tried to keep close to the 556 experience while adding some new functionality but compromising both to a degree.

6.5 Grendel seemed like a great all around cartridge and it is kinda. On paper it is more accurate at longer range than 556 and carried more power which is a total win/win. Practically, with a 16” AR-15 I was shooting better groups with 123gr 6.5 Grendel than I did with 77gr 223rem at 600yards prone or on a bench but at 800 yards the 6.5 Grendel experience was back to my 600yard experience with 77gr 223rem. The deal breaker was believing magazine makers about their Grendel magazine capacity - a 17 round magazine that only works reliably when loaded to 11 rounds is fine for stationary shooting at 600 - 800 yards but is silly when running around playing 100yards and in. I did find mags that worked loaded up to 25 rounds but once confidence is gone about a rifle loading reliably its gone.

6ARC looked new and shiny - everyone whines about the Valkyrie how its inconsistent/should have been 6mm, and large manufacturers actually want to make barrels for 6ARC unlike Grendel. So far it I’m happy with it - hell I’ve even had no issues with ASC mags loaded to full capacity. The only looming problem is 6ARC ammunition is availability; currently 6ARC is being produced by Hornady, Hornady, and I think Hornady has also announced they are making some 6ARC in the near future as well. I also have this recurring thought 6ARC really isn’t doing anything my DPMS Gen2 6.5 Creedmoor doesn’t do already.