New 6mm AR-15 pressure tested wildcat cartridge! 6MM MAX

[bowfisher]

I applaud your efforts, keep up the good work.

Since the AR15 had been around for a few decades now, most of the possibilities have been tried and accomplished. Shouldn't be a complete surprise to folks that you aren't going to gain a 50% performance increase on a newly designed AR sized case.....duh..

But there are case designs that bring incremental performance increases with minimal cost and this seems to be one of those designs. I'm a huge fan of the Grendel case size, but this case will make sense for a lot of people. For me, I would set it up for the 70gr Nos BT , throat it specifically for that and run it hard for a hunting platform. Would be a winner, IMO

I like your spirit of entrepreneurship, don't get swamped by the negativity and the naysayers, keep on keeping on!! This is what made and will continue to make this country great.

 

[LiveFire]

I applaud your efforts, keep up the good work.


I like your spirit of entrepreneurship, don't get swamped by the negativity and the naysayers, keep on keeping on!! This is what made and will continue to make this country great.

Agreed. I like variety.

 

[Swift4Yotes]

If you throat it for a 70 bt many other varmint weight bullets will be way under 2.260 oal to stay out of the lands. I've been down this road more than once.

 

[Raptor]

Interesting concept. I have the 6ARC in both an AR and a bolt gun. I have been shooting the 87 Bergers in my AR and the 90 Bergers in my bolt gun. The AR is 18" and the bolt a 22". With LVR I am getting 3050fps with the 90s in my 22" bolt gun with no signs of pressure. With my AR I am getting 2870+ with the 87s. Both guns are consistent .5 and under for 5 shot groups. What do I actually gain by going with the 6MM Max?? Pictured below is the first three 5 shot groups load testing with my bolt gun. It took me 4 rounds to get it sighted in on my 3" paster that is below these 3 groups. I love the ARC but also like the idea of your round too!!

 

[BCPB6mmMAX]

Interesting concept. I have the 6ARC in both an AR and a bolt gun. I have been shooting the 87 Bergers in my AR and the 90 Bergers in my bolt gun. The AR is 18" and the bolt a 22". With LVR I am getting 3050fps with the 90s in my 22" bolt gun with no signs of pressure. With my AR I am getting 2870+ with the 87s. Both guns are consistent .5 and under for 5 shot groups. What do I actually gain by going with the 6MM Max?? Pictured below is the first three 5 shot groups load testing with my bolt gun. It took me 4 rounds to get it sighted in on my 3" paster that is below these 3 groups. I love the ARC but also like the idea of your round too!!

That’s a good question. In a bolt gun there’s not much difference. In a gas gun there are many differences. Curved mag vs straight mag, ability to load out in straight mag pouches, Mag round count per mag. 52k psi pressure cap( cartridge/ chamber limitation? ) vs normal 55k psi pressure cap. NATO rounds successfully tested much higher. Accuracy both sub-MOA dependent on components and load. Unmodified bolt at .378 vs modified bolt at .441 . This is just a few of the differences that would affect longevity and wear in the two different gas gun configurations in the AR-15 platform.

 

[RustyPin]

Hi all,
We are New to the forum and would like to introduce ourselves and our company . I’m Brian Cook and my partner is Mike Bueschel.
We are BC Precision Ballistics and our cartridge is the 6mm MAX.
We have unlocked the code for .378 bolt head performance. After 3 years designing and testing, to include lab pressure testing at EMRTC with Dave Emary, we knew we had a winner . Paul has given us the honor to introduce our cartridge first on accurate shooters .

Why The 6mm MAX?​

The 6mm MAX is pressure tested to SAAMI standards of 55k psi. It is a brand new cartridge designed for the unmodified mil-spec .378 bolt face, and a full mass bolt carrier group. The 6mm MAX holds 35 grains of water capacity which ultimately determines the energy potential of the cartridge. In this case, 1750+Lbs of energy. Why is that so significant? The 6mm MAX can launch an 87 gr Berger VLD at 3009 fps from a 24” barrel. This produces 1749 lbs at the muzzle, 1504 lbs at 100 yards, 1093 lbs at 300 yards, 775 lbs at 500 yards, 533 lbs at 700 yards, and stays supersonic past 1000 yards. These ballistics are at standard atmospheric pressure and temperature.

Cartridge designers have struggled with 2.26 OAL, and having enough room for increased case capacity. Until recently, there hasn’t been a .378 case head cartridge available that has a 35 gr water capacity. This amount of water capacity is the engine that can power heavier, and high ballistics coefficient bullets up to 100 grs. The 6mm MAX can do this within the constraints of the AR-15, and function flawlessly. So the end result is that the 6mm MAX can push bullets 55 gr to 100 gr, and do it with the same 2.30 OAL. Some designs have emerged shorter and fatter to accommodate a bullet with better BC and enough powder for useful velocities. 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? For the cartridges with .378 case head, powder capacity is less than the 6mm MAX. For the cartridges with larger case heads, you get the same amount of powder or less than the 6mm MAX. The end result is that the 6mm MAX (35 grs) allows for a .378 mil-spec bolt face with full lug integrity and powder to push the heavies at useful velocities.

The 6mm MAX has unlocked the code on the .378 bolt face AR-15 cartridge. We were able to increase the OAL to 2.30 with the .350 Legend parent case, and magazine, which were originally designed for the AR-15, and function flawlessly. With the OAL set at 2.30 for all bullets 55 gr to 100 gr, we were able to keep bullet jump relatively consistent for the inherent accuracy across all bullet weights. We have been able to achieve 1 MOA accuracy with most bullet weights, and sub-MOA with premium target bullets.

BC Precision Ballistics has spent 3 years and thousands of hours in research and range time to get the 6mm MAX perfected. Our case is only slightly rebated for a well balanced cartridge maximizing capacity and 100% reliability. We designed the chamber for functionality in a repeater and for accuracy. Sometimes those two requirements conflict with each other as reliability requires loose tolerances, and accuracy requires tight tolerances. We consulted with many lifelong industry experts throughout the chamber/reamer design and listened to what they had to say. We utilize carbide reamers for our builds, and our tolerances are kept exact for predictable performance.

Wondering about accuracy? On Aug 6th, 2022, I competed with the 6mm MAX in F-Class with my local club the Central Texas Silhouette Association or CTSA. Full disclosure on me? I’m an old F-Open High Master. My normal competition gun is a .243 30” Bartlein barrel running 105 hybrids at 3050 fps with a stout load of H4831SC. The 6mm MAX is not a competitive F-Open cartridge by any stretch of the imagination, but I wanted to see an actual real world test of accuracy in the hot south Texas switching winds at 500 yards. I used a 24” Bartlein barreled hunting rig. This is the same bolt rifle pictured on this web site. It has 2600 rounds of testing down range, and is till holding sub-MOA with a load of H4895 tested to SAAMI standards of 53,000 psi. The load was 26.6 grs of H4895, and 90 gr Lapua Scenar-L at 2.30 OAL. This load was straight from our loading chart on this web site. After the 3rd relay my score was 568-6X. Nothing to write home about by F-Class standards, but in the world of hunting and rifle accuracy these rounds would have HARVESTED GAME.

The 6mm MAX velocities/load chart can be found on 6mmmax.Net
We are scheduled for more lab testing in Sep. 2022 at EMRTC to expand our powders and bullets as it has been struggle to find components the last two years.

Thanks
Brian Cook
6mmMAX.net

I was Years ahead of you Mr. Cook.. I had approached a few Brass Manufacturers with my idea before you: https://forum.accurateshooter.com/threads/6mm-tcu-replacement.3976975/

 

[BCPB6mmMAX]

I was Years ahead of you Mr. Cook.. I had approached a few Brass Manufacturers with my idea before you: https://forum.accurateshooter.com/threads/6mm-tcu-replacement.3976975/

I applaud your efforts, we will see if a sharp pencil has any affect on politics vs performance in the near future. Never stop innovating, it’s what makes our country great.
Brian cook

 

[RustyPin]

I applaud your efforts, we will see if a sharp pencil has any affect on politics vs performance in the near future. Never stop innovating, it’s what makes our country great.
Brian cook

The original intention was to duplicate the old US military 6mm SAW from the late 60's-early 70's. Seeing Russia has since implemented nearly the same case in thier very own 5.45×39mm. In fact I had contacted Winchester and I'm sure others regarding a Case that mimicked the 9mm Luger but longer to be introduced into the US market for the sole purpose of using in the AR-15 as a replacement for the 5.56 in either .224 or .244 Calibers but first we had to get the Case into production. Winchester's marketing or developement team elected to use the rebated rim to match the Bolt in the 5.56 Cartridge. (Ammunition Developers like Winchester have many if not hundreds of Cartridge designs filed away in the dark recesses or super top secret locked down marketing Vault and I'm sure they're not going to be giving anyone else credit for what they invested to bring the 350 Legend to market let alone me for some random email or Facebood instant message I sent out).

The problem with the 244-350 Legend ("6mm MX" which I had coined it long ago with letters from my surname circa 2019) is the lack of room for the longer pills in the short 2.26" AR-15 Magazines. Sure you can put the shorter 60 Grain Pills into use and see interesting and exciting speeds, but the same can be had with the 6mm TCU using the old 5.56 case that preceeded it. ("AR-15 SUPER").

Now I obviously can't claim that I invented the 350 Legend as that would be absolutely proposterous as it would be the same as someone claiming they invented the 9mm Luger. I published an entire write up in my Facebook Wildcat Group regarding the 350 Legend case as soon as it became available. I had posted a diagram of what a .224 Caliber and .244 Caliber version would look like along with estimated Case Capacity and cross sectional information. Later I had to remove all my Wildcat information and temporarily close the Group due to what seemed like pilfering my Intellectual Property and perhaps I had been overzealous in pushing my agenda. As it was, I had done much ground work in the layout of many Cartridges.

However lets be honest and give credit to the original 6mm-SAW developed by the US Government for Military use and given the nearly exact overall size and dimensions of the 6mm-350 Legend's nearly identical in performance and case capacity, which has oddly if not questionably vanished into obscurity.

Here are some points regarding the actual cases that are in use:

The 9mm Luger having an advertised Base of .391, the original 6mm SAW developed by the US Government advertised @ .404 inches base diameter, the Russian 5.45×39mm listed as .394 and the Legend being listed as .390 and finally and lastly China's 5.8 x 42mm advertised @ .409 inches. Which without knowing the exact internal cross section used in the stamping of the brass during the manufacturing process would and can be only assumed within a few thousandths of each other.

I would also like to add as an example the "400 Legend" which is nothing more than the 6.5 Grendel Case that has been stretched and given a rebated rim the size of the 6.8 SPC & is nearly identical to the old 7.62x45 developed in Czechoslovakia prior to 1952 I might add. (Bet you guy's didn't know that did you?)
So who is going to "invent" the 6mm-400 Legend/7.62x45? I'm sure I can find my personal designed schematic of it somewhere or even maybe if you digged long and hard enough find one from the 1950's.

Now I realize this is not the intent of this Forum, as my intent is not to start trouble and finger pointing but rather to educate the masses of what actual facts or part of the facts given we had all the actual data available. Lastly why was the 6mm-SAW buried so well in fact so well the manufacturing plant and all the machines that were in use had reportedly vanished? Why wasn't the design of the 6mm-SAW case made available for public use in the 1970's after Congress denied the Military's request for the Cartridge? After all we've had to come a long round about way to duplicate what the Taxpayers already paid for once just to have again four decades later. Thanks everyone for reading and I do apologies for the extremely long post, but it's just something I felt needed to be addressed.

 

[wkndwarrior]

Interesting thread, I wonder how one of these compares to a 6mm BRX AR?
I don't see any complete uppers or packages on the website.