New Cartridge, 6mm MAX

[Shadow9mm]

Found a video here, explains just about everything. https://www.youtube.com/watch?v=UqfpMxci168

My synopsis,

6mm MAX (is SAAMI)
designed by Brian with BC Precision ballistics
Being marketed through Sons of Liberty Gun works
Partnering with Starline for brass
supposed to be available to the public in november 2023

uses standard 223/5.56 bolt face (only needs a barrel change)
350 legend is the parent cartridge
Geared towards PRS
designed around a 20in barrel

58g v-max 3528fps
85g Speer BTSP 3015fps
90g eldx 2826fps

Seems they considered the 6.5 grendel type 2 bolt face used by the 6mm arc to be problematic and wanted something with a standard 223/5.56 bolt face size. They said whey wanted to increase case capacity and burn more of a slower powder to keep pressured down. 6mm max has slightly better water capacity, but based on the shape of the cases I would wager actual capacity for powder will be significantly reduced due to how far the bullet is seated into the case.

[stagpanther]

It took me many years to learn this lesson: let others blow their guns up first upon new cartridge roll-out, wait at least a year is my new mantra. they don't call it bleeding edge for nothing.

[Shadow9mm]

Originally Posted by stagpanther

It took me many years to learn this lesson: let others blow their guns up first upon new cartridge roll-out, wait at least a year is my new mantra. they don't call it bleeding edge for nothing.

My dad always said, "Be not the first by whom the new is tried, nor yet the last to lay the old aside."

[stagpanther]

Dave Kiff of PTG fame designed a 234 nosler out of the 22.

[Pumpkin]

Does this mean that the 6mm REM is a Super Max?

[Shadow9mm]

Originally Posted by Pumpkin

Does this mean that the 6mm REM is a Super Max?

Sounds too much like a prison.

[Pumpkin]

Especially if you have a 6mm (I do) and don’t reload for it. I stocked up on WW brass 30 years ago. The new cartridge sounds sweet, I guess names have to be catchy these days.

[taylorce1]

I haven't watched the video yet, but I will. They might have geared it toward PRS, and that means the 90 grain ELDX is really the only bullet shooters will want. The biggest issue is and always will be with AR-15 is magazine space.

[stagpanther]

I watched the video; I have to be honest they laid a bit much on the "what's wrong with grendel" bit and a bit heavy on the super-magic of their cartridge attaining 3000 fps (I'm stunned)--I'm suspicious when I see that kind of stuff--but that's just my gut reaction and would love to see the latest greatest slice of bread come true.

[ammo.crafter]

I'll stick with my 6 m/m Rem that I built on a German Mauser 98k re-barreled to the 6.

Hits thumb tacks at 100 yards.

[44 AMP]

So, yet another wunderpatrone intended for match shooting from an AR-15,,,how many of those do we have now???

Probably something fun for the people into those games, but pretty much a yawn for the rest of us.

[taylorce1]

I know the .350 Legend case is a little larger at the base than the .223 Rem. However, I wonder the difference in case capacity. The guy claimed more powder capacity with the Legend case. BC Precision claims 35 grains of water, that seems optimistic.

I shoot the 6X45 and 6X47 Rem, getting over 3000 fps with 70 grain bullets isn't hard. I can also run 85 grain bullets in the high 2900 fps. I know a grain or two of powder is significant in a small case, but I'd think to run the ELDX in an AR-15 mag they'd have to shorten the case a little.

[gwpercle]

If the new "wonder cartridge" is still around after 10 years ... I'll take a look at it .

So many wonderful rounds have jumped out , made a big splash and promptly faded into oblivion ... I don't need something I can't get ammo or cases or even loading data for .
Gary

[Shadow9mm]

Thats why i went 6arc. Good load data, some factory availability, and i can make brass from a few other cases if worse comes to worse. Plus its been a few years since the release, more manufacturers are making it, and theres a government contract attached. It might die off, but i have what i need to keep shooting it for a long while.

[FrankenMauser]

Meh. Stubby neck and not much room for an ogive.
Gonna have the same problems as 6x45mm (and .25-45 Sharps).

I built my 6x45mm thinking it could be a dual purpose rig - small big game, and 'walking varminter' kind of role.
Turns out that I can't really use a hunting bullet heavier than 85 gr without the ogive being half way down the neck.

It gets a lot of varmint bullets now. It does great with them, and they leave the muzzle at higher velocity than the same weight would in a .223/5.56. But the 'big game' role is a one trick pony: 85 gr Partitions, or even lighter cup-and-core bullets from other makers.

Unless Hornady offers a stubby-nosed (non-ELD) ELD-X, I don't see that working out very well.
(Same for ELD-M.)

[taylorce1]

Originally Posted by FrankenMauser

I built my 6x45mm thinking it could be a dual purpose rig - small big game, and 'walking varminter' kind of role.Turns out that I can't really use a hunting bullet heavier than 85 gr without the ogive being half way down the neck.

What action did you build your 6X45 on? I built mine on a Savage, and I can feed 105 gr BTHP bullets from the mag with no issues of the ogive being inside the case mouth. Now my 6X47 Rem is a different story I used a slow twist barrel so I'm limited to 70 grains for the most part, I've shot 80s but the groups always open up larger than I want.

I hope this 6mm Max takes off. I might rechamber my 6X45 since it has a 7 twist barrel and more mag space than an AR. I might be able to run some 105-115 gr bullets as well. I really don't need that ability, but I like options.

[FrankenMauser]

My 6x45 is an AR. So, a more appropriate comparison to 6mm Max.

One of these days, I'll rebuild a short action bolt gun for the cartridge.
I bought a Marlin XS7 in .223 for the job, but it had a lot of extractor problems because it was a Remlin from Mayfield (somewhere in the transition from North Haven, Remington made the extractor slot wider in the bolt heads and it caused a lot of binding and jamming). So that got converted to take AR mags and was sold off with a bushel of spare bolt and magazine parts -- to a guy building the old 6x47 (.222 Rem Mag version), who was insistent that he could fit it into AR mags.
(He was unsuccessful, of course, and went back to the box mag. )

[44caliberkid]

Originally Posted by stagpanther

It took me many years to learn this lesson: let others blow their guns up first upon new cartridge roll-out, wait at least a year is my new mantra. they don't call it bleeding edge for nothing.

Agree here. I jumped on the 22 Nosler train when it first rolled out and six months later the 224 Valkyrie came out and the support for the Nosler fell flat. Mine never shot that well anyway, I had 223/5.56 AR’s that were much more accurate.

[MarkCO]

Originally Posted by taylorce1

I haven't watched the video yet, but I will. They might have geared it toward PRS, and that means the 90 grain ELDX is really the only bullet shooters will want. The biggest issue is and always will be with AR-15 is magazine space.

Yep.

I suspect the 6mm Max won't do well as the PRS shooters want (need) 105 to 115 6mm bullets, not 85 to 100 grain bullets. When I pass 107 in the PCC, just not enough velocity to matter anymore.

It took me many years to learn this lesson: let others blow their guns up first upon new cartridge roll-out, wait at least a year is my new mantra. they don't call it bleeding edge for nothing.

Agree. That is why the .450BM, .450Corvette, 300BOs, 224Valkyrie, .350L, and several other calibers for the small and Large frame ARs are gone.

Small Frame, 223/5.56, 6.5PCC, 9mm (blowback) and 10mm are all I have left. 6.5CM and .308 in large frame.

I've spent enough of my own money, and that of clients doing testing and R&D of parts and cartridges on the AR patterns that I could retire if I had it all back.

[44 AMP]

uses standard 223/5.56 bolt face (only needs a barrel change)
350 legend is the parent cartridge
Geared towards PRS
designed around a 20in barrel

Seems to me to be tailor made for a very specific application, and in an AR-15 class rifle.

I have a couple questions, since I'm not familiar with some things,

PRS is what? Is it Precision Rifle Shooting?? (and what precisely is that??)

If it is long range shooting, why the focus on 20" barrels??

[MarkCO]

Originally Posted by 44 AMP

Seems to me to be tailor made for a very specific application, and in an AR-15 class rifle.

I have a couple questions, since I'm not familiar with some things,

PRS is what? Is it Precision Rifle Shooting?? (and what precisely is that??)

If it is long range shooting, why the focus on 20" barrels??

PRS is a league, Precision Rifle Series. They used to have a Gas Gun series, but that went away, they are trying to bring it back. Almost no-one shoots an AR in PRS, or NRL (National Rifle League which is a similar, but different format). AR15s are, for precision shooters, almost entirely used in Team matches for the Carbine Shooter. Most of those style matches are not PRS or NRL matches. Personally, I use my 16" 3Gun rifle with a 3-15 optic as the Carbine shooter, and I am usually near to top among the carbine shooters. Carbine shooters, in those matches, typically shoot the closer of 6 to 8 targets. Like in Team Safari and the Sniper Adventure Challenge, the carbine shooter shoots 4 targets and the bolt gun shooter shoots 8. Those targets can be from 200 to 1200 yards. Most times, the carbine shooter is shooting the 4 closest, so maybe 200 to 800 yards. At times, I will shoot the furthest target first so my bolt gunner can get a wind read and prepare while I shoot the closest three.

20" is a bit short for bolt guns and a bit long for gas guns.

It is really not "tailor made" for PRS in any way that I can see. It will, at best, be an outlier make it work option, if any.

PRS is typically 2 to 10 targets on a stage. You get to see the stage, range the targets, make a plan prior to the start. Then you have 2 minutes to hit the targets. Stages vary. In some, you have to hit a target to move on, in others targets can be skipped. Points can vary as well, but are typically 1 point per hit.

Competition Dynamics hike, spot and shoot matches require the competitors to shoot blind stages where they have 4 to 6 minutes to find, range, and engages 4 to 8 targets. 1 point per hit, carbine unlimited rounds, bolt gun 1 round per target only. They can have pistol and assault stages as well.

NRL is 4 targets, also a hike and spot, blind stages. They can be 1 position, 2 targets and 2 positions or 1 target and 4 positions. 1st round hit is 2 points, 2nd round hit is 1 point, then move on.

[bamaranger]

I'm lost in the acronyms. I thought PRS was "practical rifle shooting", a sort of IDPA shoot on steel at rifle like distances (whatever that is)? If PRS is a league, is their such a thing as PR (Practical Rifle) being a type of competitive shooting style/match? I thought the unknown distance shoots from improvised field positions on steel with time were PR matches. A semi seems it would offer some advantage on multiple targets or mutiple hits required stages, a sort of Designated Marksman Rifle offering.

[44 AMP]

That you for the explanation and context for that abbreviation used here.

Context helps, but context alone is seldom enough for accurate understanding when the abbreviation comes from a specific, and narrow field.

PRS could stand for "pretty ripe squash" and perhaps, somewhere it does, but the context was rifle cartridges, so squash was a low order possibility.

The best practice when writing using abbreviations and acronyms (abbreviations which spell a pronounceable word, such as RADAR, or LASER) is to spell out the full name or definition the first time in the document that the abbreviation is used. After that using only the letter abbreviation is acceptable.

SO, other than perhaps being a slightly better "mousetrap" for certain specific marksmanship games, does the 6mm Max have anything to recommend it over several other cartridges that have better ballistic performance??

Other than fits in an AR 15, I mean??

[stagpanther]

"Missed it by that much."

[taylorce1]

Well I looked at the reloading data on BC Precisions (BCP) website. The trim length on brass is 1.715", so they maximized case capacity. 2.26" is the what the case overall length (COAL) is for an AR-15 magazine.

BCP claims 35 grains of water capacity vs.

Originally Posted by BCP

When comparing the water capacity of 24 Nosler (29 grs), 6.8 SPC (35 grs), 5.56 x45 NATO (28.5 grs), 6×45 (29 grs), 6 ARC (34 grs), 6.5 Grendel (35 grs), .224 Valkyrie (34.5 grs), and what do we get?

BCP talks about the issues of a 2.26" coal, but also states a COAL of 2.3" for the Max. This may, or may not work in certain AR magazines. More than likely you'd have to modify a magazine to work with that COAL. I'm doubtful it is as plug and play as they talk in the video, especially with bullets that exceed 1" in length.

I just really don't see this cartridge making a big splash. I will say, I do like the concept. It would be a lot of fun to play with in a bolt action rifle with 2.4" or longer COAL capacity magazine with a proper throat for the extra length of seating. However, in a bolt action the ARC fits that role nicely.