New Cartridge, 6mm MAX

[MarkCO]

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]

PRS v. PR

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.

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.

 

[MarkCO]

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.

PRS is certainly Precision Rifle Series. Practical Pistol encompasses USPSA, IDPA, GSSF, even SASS and others. Some sub-groups such as "action" or "tactical" pistol can be used by some folks. Practical Rifle also encompasses many formats.

PRS, like USPSA has become a race gun competition...less practical and more about the gear specifically used therein, and nowhere else. NRL used to have a "Race Gun Series" but dropped it and focused on the Hunter series, that is as I described above. It is more practical, but the PRS shooters have come over to it and it has, to some degree, become a little less demanding gear driven sport as well.

Yes, there are absolutely "Practical" rifle matches. The NRL is still close and Competition Dynamics runs many of them such as the Steel Safari, Burris Optics Team Challenge, Team Safari, Sniper Adventure Challenge. Back Country Extreme is a collaboration match between CD and NRL. There are also several stand alone matches that are practical, long range matches. IPSC (USPSA) has rules that allow for practical rifle matches, both MOR (manually operated rifle) and Gas gun and there are matches that use those rulesets. NRL22 is a thing as well and one of our young ladies from the US just placed 2nd Lady at the International 22RF match. Some clubs run matches, such as the AR vs AK matches, one held local to me this week in fact. Some smaller, local or regional matches do offer an unknown distance match, some a bipod and a bag only, from improvised field positions, but there are few, if any, national level matches that run that old school style anymore.

 

[Jim Watson]

My cynical view is that if you are a frequent shooter you can buy the Cartridge Of The Month and will shoot out the barrel before it is obsolete and supplies get scarce.
Then you can rebarrel for the current fad round.

 

[USAF Ret]

My cynical view is that if you are a frequent shooter you can buy the Cartridge Of The Month and will shoot out the barrel before it is obsolete and supplies get scarce.
Then you can rebarrel for the current fad round.

This comment wins the internet for the day.

 

[MarkCO]

My cynical view is that if you are a frequent shooter you can buy the Cartridge Of The Month and will shoot out the barrel before it is obsolete and supplies get scarce.
Then you can rebarrel for the current fad round.

Um, there is some truth there. I know several guys who have had 5 or 6 cartridges in barrels spun up for the same rifle.

I've done it a few times.

 

[44 AMP]

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.

I understand "fun to play with", and we each have our own definitions of "fun". And I understand putting these "max for AR size" rounds into a bolt gun so you can get a little more out of them by choosing actions with more magazine room, and barrels throated the way you want.

What I don't get is WHY BOTHER??

When you go to a custom bolt gun (or single shot) your options open up tremendously. You are no longer limited to things that fit, and run in an AR.

And, since you're not, why NOT go to a cartridge that is more flexible and can provide a significant ballistic improvement?? You can also go to a longer barrel easily and get even more performance.

OR you can keep a short tube and still get more, I've got a couple of Remington rifles, a .243 with a 20" and a 6mm Rem with an 18.5" and both of them will beat the specs given for the 6mm Max for velocity with given bullet weights. Now, they are old hunting rifles, neither is throated for the extra long match bullets popular now, but they could be, and if I were building a new bolt gun I'd have it throated to handle the bullets I wanted to shoot, if the standard throat wasn't optimal.

The 6mm Max holds what?, 35gr or so, of powder? IF you're in a bolt gun, I don't see any disadvantages to using a cartridge that holds 50gr of powder, and numerous advantages to one that does.

Do what makes you happy, I have several niche rounds I really enjoy using, finding out for myself what they do, and don't do well.

 

[FrankenMauser]

The trim length on brass is 1.715"

Interesting. I trim to 1.750" for 6x45mm.
I honestly don't know what "standard" is. That's what I ended up needing to trim to for uniformity.
Anyway, 6mm Max is only .035" shorter. That doesn't do much for increasing bullet selection.

2.300" COAL adds another 0.040". That might be enough to get into bullets like the 95 gr SST, but it still has the secant equivalent of a 6S ogive, I believe. That is still nowhere near VLD/ELD territory.

And I have still not found a good magazine that lets me run more than about 2.273" COAL. (And I have moved back to 2.255-2.260" for reliability, anyway.)

ASC was once renowned for their mags allowing up to 2.290" COAL. But the magazines that I got from them were absolute garbage. Sure, I could run about 2.280" COAL, but they also had oversized reinforcing/guide ribs stamped into the body, which caused rim-lock by pinching the bases together. Rim-lock with a rimless cartridge!

It is more practical, but the PRS shooters have come over to it and it has, to some degree, become a little less demanding gear driven sport as well.

I have been seeing this in NRL22, as well. The PRS guys are always trying to turn NRL22 stages into PRS stages; and club/bonus stages are nearly always going to seem more appropriate for a PRS match than an NRL22 match.
PRS22 never went anywhere, because it was just regurgitated PRS stages in a more compact, but even more challenging, form. But now they're trying to push it into NRL22.

We had two this past Saturday, in fact. One was approximate ranges - targets within +/-10 yards of specified distance. Locate and engage 5 targets (scattered over the range) of varying sizes and shapes, two shots each, in order, from about 107-350 yd, no rangefinder allowed. (One of the targets was more than 20 yards, and one almost 40 yards, farther than the distance specified. )

The other was unknown ranges, known size, no rangefinder allowed, 5 targets, two shots each. "Use your scope reticle to range, or just guess and hope." Ended up being something like 104, 117, 141, 171, and 187 yd. Easy with a centerfire. Not so easy with .22 LR and a reticle that isn't meant for ranging.

In my case, I also had a cognitive freeze and couldn't remember *how* to range with MoAs. So I used dope where I could and just guessed [mostly unsuccessfully] on the rest. My eyeballs had the ranges pretty close. I just didn't have enough dope for that rifle yet.
Most squads saw performance increase as more shooters shared what they dialed for each target, and subsequent shooters benefited from the knowledge. But our squad started small and had people leave, and ended up with only myself and an airgun guy on that stage. Our dope and feedback were not useful for each other.

 

[taylorce1]

What I don't get is WHY BOTHER??

To give stodgy old guys like you something to complain about!

Then there is also the fact that experimenting with cartridges keeps me interested. Then there is a real world application for any 6mm cartridge, here in Colorado. Simply a .224 calbier isn't legal to hunt big game with, and a diminutive cartridge like the 6mm ARC and this 6mm Max is perfectly capable of handling deer sized game.

Then there is also the fact that this a forum for discussing everything firearms. It's a natural progression going from an AR‐15 cartridge to other platforms. Do you think the .223 Rem/5.56X45 was going to stay exclusive it semi-auto firearms?

And I have still not found a good magazine that lets me run more than about 2.273" COAL. (And I have moved back to 2.255-2.260" for reliability, anyway.)

You'll need to modify a magazine, like in this picture from the Daily Bulletin.

 

[44 AMP]

To give stodgy old guys like you something to complain about!

I don't know if it is stodgy or not, what I'm looking for when I say "why bother" is you dang kids explaining why you're interested in, and doing it.

Ok, so using the small "diminutive" 6mm for deer IS a valid reason, to me. I tend to favor the more is generally better end of things, but finding out what is the lower end of reliably and legally taking deer is entirely something I can understand.

Doesn't seem like that round is intended for hunting, but if it works, it works.

play on dude!

 

[FrankenMauser]

You'll need to modify a magazine, like in this picture

I am aware of various window and slot modifications, but uninterested.
I've seen too many issues with feed lip flex.

I run what works in the magazines that I use.

 

[Pumpkin]

I would be happy if I could just keep up with all the acronyms, not just in the firearms world either! Seems like every day there is a new acronym or new word to describe the same thing. I wonder, how many of the old dogs, 243, 270, 30-06, etc would equal so many of these new calibers if just given a longer throat and a faster twist.

 

[taylorce1]

I don't know if it is stodgy or not, what I'm looking for when I say "why bother" is you dang kids explaining why you're interested in, and doing it.

Then what is the point of The Firing Line?

 

[MarkCO]

I would be happy if I could just keep up with all the acronyms, not just in the firearms world either! Seems like every day there is a new acronym or new word to describe the same thing. I wonder, how many of the old dogs, 243, 270, 30-06, etc would equal so many of these new calibers if just given a longer throat and a faster twist.

And a 40 degree shoulder for the case (AI), and there you go.

PS: AI = Ackley Improved.

 

[Pumpkin]

My bad, I had an old friend (in the 80’s) that had a 700 BDL with a 26” 280 Ackley Improved with a faster than normal twist. The barrel contour was also a little heavier if I remember.

 

[stagpanther]

The problem with AR's is that they were designed for standardized cartridges; it's really the length of the magazine well in the receiver that limits the variety/performance of new cartridges. some cartridges will not play nice with existing magazines when stacking, thereby bulging the magazine sidewalls and increasing the chances of a failure to feed. There have only been a few rare attempts (like Remmie's AR30) to introduce alternative mag well size receivers and they have generally flopped with the possible exception exception of ultra-expensive big cartridge custom guns like Noreen's (which as far as I know you cannot customize yourself).

 

[FrankenMauser]

I wonder, how many of the old dogs, 243, 270, 30-06, etc would equal so many of these new calibers if just given a longer throat and a faster twist.

I have had that conversation many times - especially in regard to the 6.5 wonders.
They're just .270s with longer throats, (sometimes) faster twists, and an actually useful bullet selection.

In about 2010, I had a gunsmith rebarrel a Ruger 77VT to .243 Win. Except we kept the chamber super tight, gave it a loose neck, used a 9 twist barrel, and throated it just a bit longer than usual.
It spits out fired cases that are under SAAMI minimum and have no measurable expansion, except in the neck.
It does everything that 6mm Creedmor does, but at slightly lower pressure. I have to burn about 4% more powder, because of the greater case capacity; but that is the cost of being ahead of its time.

Feeding that rifle is now a little tricky, because the chamber was cut based on Remington's brass with notoriously sub-minimum SAAMI dimensions, and that brass is no longer available. But that is another subject.