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A google search comes up with nothing........
 

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I was speaking with DocGKR on the phone last year trying to figure out what would be the best duty round for the 6.8 and he mentioned the 7mm Murray. I don't know much about it by he said it was a bad ass new round that surpassed the 6.8 and .308 and would be the shizzle! I get the impression it wouldn't fit in a standard 5.56 type mag well but probably required a new weapon. Maybe he could jump in here and give more details?
 

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IIRC it's the 7.62x45 Chech necked down. It's too long for the AR-15.
 

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It's another Murray/Holland round but this time they just designed the best combat cartridge with no restrictions like it has to fit in an existing AR platform.
 

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Yep Constructor has it.
Chechz 7.62x45 necked down to 7mm which actually makes it 7x46. It is looked to as being an overall replacement round if you did not have to meet the mag well restrictions of the AR. It can be loaded with a large variety of bullets to allow for both long Range crew served combat rifles etc... It would effectively be able to replace both the 5.56 and 7.62. But again this is not to fit in an AR mag well.Modified Robison XCR and Massads would work.
 

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Here is a posting from DocGKR on another forum (sorry the pics didn't turn out):

Interesting observations.

As discussed previously, while the 6.8 mm has repeatedly demonstrated outstanding terminal performance in JSWB-IPT testing, FBI BRF testing, USMC testing, and the recent CTTSO/TSWG MURG Congressional demonstration, keep in mind that the 6.8 mm design is a compromise that does not maximize assault rifle terminal performance, as it is constrained by the requirement to fit and function in the 5.56 mm M4/M16 magazine. The 6.5 mm Grendel is inhibited by this same limitation.

Primary focus during SPC cartridge design was to offer improved terminal performance, accuracy and flight characteristics from CQB range out to 500 meters from the M4 type platform compared to all existing 5.56 mm loads. The SPC was required to be easily retrofitting to current SOF 5.56 mm rifles (HK416, Mk18, M4, Mk12, M16) and be adaptable to proposed future systems (SCAR-L/Mk16, XM-8). The 6.8 mm SPC easily meets these criteria and has proven extremely reliable and durable in extensive functional testing.

Below is a 6.8 mm Horn 115 gr OTM shot fired from a 12” barrel into a bare gel block at 100m. MV = 2466 f/s, Impact Vel = 2263 f/s. Pen = 13.5”, NL = 1”, Max TC = 4.5” diam at 4.5” depth, extending from 1 to 9”. RW = 85.6 gr.


---------------------------------

If freed from the M4/M16 platform imposed design compromises that limit both the 6.5 mm Grendel and 6.8 mm SPC, an “idealized” combat rifle cartridge, can be explored. As noted, virtually every wound ballistic test in the last 100 years points to a 6.5-7mm cartridge as offering the ideal combat performance--be it the 1920’s era .276 Pederson, the post WWII .270 & .280 British cartridges, or the newer SPC program.

While at USAMU, Cris Murray, one of the co-designers of the 6.8 mm SPC simultaneously developed an “ideal” combat rifle cartridge, with none of the M4/M16 platform imposed design compromises that limit both the 6.5 mm Grendel and 6.8 mm SPC. Murray’s 7 x 46 mm, offers better range and terminal performance than 6.5 mm Grendel, 6.8 mm SPC, or any other common assault rifle cartridges, including 5.45 x 39 mm, 5.56 x 45 mm and 7.62 x 39 mm. Since the 7 x 46 mm is based on the proven Czech military 7.62 x 45 mm cartridge, it has an established record feeding and functioning in both magazine and belt-fed full-auto fire. Likewise, recoil appears manageable and weapons remain controllable in FA fire, just as with the Czech cartridge. Like the 6.8 mm, the 7 x 46 mm is optimized for shorter barrels and larger magazines than the heavier, bulkier, and harsher recoiling 7.62 x 51 mm/.308 cartridge. In addition to Murray’s 7 x 46 mm, the older FN 7 mm's (7 x 44 mm, 7 x 47 mm, and 7 x 49 mm), as well as the newer 6.5 mm Creedmore are worthy of consideration. For that matter, revisiting the British .270/.280 wouldn’t be a bad idea. Keep in mind that the OAL of these cartridges is a bit too long to fit into the M4/M16 or other 5.56 mm size weapons/magazines



As a result, these cartridges should ideally be used in all new rifle designs optimized for their characteristics.

Below is a 7 x 46 mm shot from a 16” barrel, using the 120 gr Hornady OTM fired into a bare gel block at 100 meters. MV = 2801 f/s, Impact Vel = 2529 f/s. Pen = 15.5”, NL = 1.5”, Max TC = 6” diam at 5” depth, extending from 1.5 to 9”. RW = 84.2 gr.



Hard armor of NIJ Level III/SAPI protective levels will stop ALL standard military OTM and FMJ, including mild steel core ammo, such as 5.45x39 mm M74 FMJ, 5.56 mm M193 and M855 FMJ along with Mk262 OTM, 7.62x39mm M43 FMJ, 7.62 x 51 mm M80 FMJ and M118LR OTM, 7.62 x 54 mm Type L FMJ, and .30-06 M2 FMJ. This same Level III armor can be easily be penetrated by any of the same calibers listed above when using common military AP ammo.

If you want to stop most rifle AP ammo such as the .30-06 M2 AP "black-tip, all you need to do is use NIJ Level IV/eSAPI type hard armor. Yet even that can be penetrated using the right ammunition... Penetrating armor is not about caliber--it is about bullet construction.


As I have publicly stated previously, we have three choices:
-- Adopt improved barrier blind 5.56 mm ammunition for our current weapons.
-- Adopt an improved intermediate assault rifle caliber, like 6.5G or 6.8 SPC, that can be retrofitted to our current and near term weapons.
-- Adopt a larger case capacity combat caliber, like 7 x 46 mm or an enhanced 7.62 x 51 mm load, along with a new modern rifle system.

A Mk16 SCAR-L in 6.8 mm would indeed be nice…how about a 7x46 mm Magpul Massood?
 

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Sound interesting :shock:

Just a question why cant you put it in the AR10 platform?? yea its Tad bigger but you can save weight im sure some where else..and would have plenty of room in there...far as i remember Ar10 was the grampa of the ar15..its been around long time like the m1a..so its proven system
 

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You can and it has been done. MGI with the magwell conversion for use with a mod M14 mag + the Oly WSSM upper. That gets you everything you need.
 

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7 x 46 mm could be put into an AR10/SR25, however weapons of this type, including the SR25, Mk11, M110, KAC SR25K, etc... have NOT proven to be very reliable in combat. In addition, if you are going to go to a large weapon like an AR10/SR25, you might as well stick to a .308 based system, be it 7.62 x 51 mm, 7 mm-08, .260 Rem, or 6.5 Creedmore.

As discussed previously, while the 6.8 mm has repeatedly demonstrated outstanding terminal performance in JSWB-IPT testing, FBI BRF testing, USMC testing, and the recent CTTSO/TSWG MURG Congressional demonstration, keep in mind that the 6.8 mm design is a compromise that does not maximize assault rifle terminal performance, as it is constrained by the requirement to fit and function in the 5.56 mm M4/M16 magazine. The 6.5 mm Grendel is inhibited by this same limitation.



Primary focus during SPC cartridge design was to offer improved terminal performance, accuracy and flight characteristics from CQB range out to 500 meters from the M4 type platform compared to all existing 5.56 mm loads. The SPC was required to be easily retrofitting to current SOF 5.56 mm rifles (HK416, Mk18, M4, Mk12, M16) and be adaptable to proposed future systems (SCAR-L/Mk16, XM-8). The 6.8 mm SPC easily meets these criteria and has proven extremely reliable and durable in extensive functional testing.

Below is a 6.8 mm Horn 115 gr OTM shot fired from a 12” barrel into a bare gel block at 100m. MV = 2466 f/s, Impact Vel = 2263 f/s. Pen = 13.5”, NL = 1”, Max TC = 4.5” diam at 4.5” depth, extending from 1 to 9”. RW = 85.6 gr.


---------------------------------

If freed from the M4/M16 platform imposed design compromises that limit both the 6.5 mm Grendel and 6.8 mm SPC, an “idealized” combat rifle cartridge, can be explored. As noted, virtually every wound ballistic test in the last 100 years points to a 6.5-7mm cartridge as offering the ideal combat performance--be it the 1920’s era .276 Pederson, the post WWII .270 & .280 British cartridges, or the newer SPC program.

While at USAMU, Cris Murray, one of the co-designers of the 6.8 mm SPC simultaneously developed an “ideal” combat rifle cartridge, with none of the M4/M16 platform imposed design compromises that limit both the 6.5 mm Grendel and 6.8 mm SPC. Murray’s 7 x 46 mm, offers better range and terminal performance than 6.5 mm Grendel, 6.8 mm SPC, or any other common assault rifle cartridges, including 5.45 x 39 mm, 5.56 x 45 mm and 7.62 x 39 mm. Since the 7 x 46 mm is based on the proven Czech military 7.62 x 45 mm cartridge, it has an established record feeding and functioning in both magazine and belt-fed full-auto fire. Likewise, recoil appears manageable and weapons remain controllable in FA fire, just as with the Czech cartridge. Like the 6.8 mm, the 7 x 46 mm is optimized for shorter barrels and larger magazines than the heavier, bulkier, and harsher recoiling 7.62 x 51 mm/.308 cartridge. In addition to Murray’s 7 x 46 mm, the older FN 7 mm's (7 x 44 mm, 7 x 47 mm, and 7 x 49 mm), as well as the newer 6.5 mm Creedmore are worthy of consideration. For that matter, revisiting the British .270/.280 wouldn’t be a bad idea. Keep in mind that the OAL of these cartridges is a bit too long to fit into the M4/M16 or other 5.56 mm size weapons/magazines



As a result, these cartridges should ideally be used in all new rifle designs optimized for their characteristics.

Below is a 7 x 46 mm shot from a 16” barrel, using the 120 gr Hornady OTM fired into a bare gel block at 100 meters. MV = 2801 f/s, Impact Vel = 2529 f/s. Pen = 15.5”, NL = 1.5”, Max TC = 6” diam at 5” depth, extending from 1.5 to 9”. RW = 84.2 gr.



Hard armor of NIJ Level III/SAPI protective levels will stop ALL standard military OTM and FMJ, including mild steel core ammo, such as 5.45x39 mm M74 FMJ, 5.56 mm M193 and M855 FMJ along with Mk262 OTM, 7.62x39mm M43 FMJ, 7.62 x 51 mm M80 FMJ and M118LR OTM, 7.62 x 54 mm Type L FMJ, and .30-06 M2 FMJ. This same Level III armor can be easily be penetrated by any of the same calibers listed above when using common military AP ammo.

If you want to stop most rifle AP ammo such as the .30-06 M2 AP "black-tip, all you need to do is use NIJ Level IV/eSAPI type hard armor. Yet even that can be penetrated using the right ammunition... Penetrating armor is not about caliber--it is about bullet construction.



7.62x33mm, 5.56x45mm, 6.8x43mm, 7.62x39mm, 7.62x45mm, 7x46mm, 6.5x47mm, 7.62x51mm, 7.62x63mm

As I have publicly stated previously, we have three choices:
-- Adopt improved barrier blind 5.56 mm ammunition for our current weapons.
-- Adopt an improved intermediate assault rifle caliber, like 6.5G or 6.8 SPC, that can be retrofitted to our current and near term weapons.
-- Adopt a larger case capacity combat caliber, like 7 x 46 mm or an enhanced 7.62 x 51 mm load, along with a new modern rifle system.
 

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Thanks DocGKR. Great informative post. I can see all these recent developments "confusing" the military evaluation and procurement system so much they'll end up doing nothing.
 

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Cris Murray has recently written:

"I've got factory made 7x46mm brass from Privi Partizan. Their brass is made straight from long 7.62x39 blank cartridge case they make and has the nice thick Russian rim, I want. Hopefully I'l be able to finish the pressure and powder tests this time, I'm trying to keep the speed at 2650 fps with a 130 gr projectile with pressure below 50K; all this out of a 16.5in barrel. Our last tests were good, but I need to document them with telemetry."
 

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That is awesome. The one thing that will make or break a cartridge, cases that are ready made not having to be formed by the end user.
 

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Thanks DocGKR-

While I haven't played with these, based on what I've seen/read, I would get that warm and fuzzy feeling if the Army adopted this cartridge and put it in a platform like the Magpul Masoud (like the Masada, but uses 7.62 x 51mm as it's baseline calibre). I'm sure that Magpul could manufacture PMags for the new cartridge/weapon system's magwell.

If Magpul were to set up a manufacturing agreement with LWRC, maybe they could also incorporate LWRC's OBA (Open Bolt Automatic) system into the design for use as a SAW. :wink:
 

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How about an "intermediate length" AR upper and lower receiver to handle this round? Would expanding the lower receiver in the magwell area and a similar expansion of the upper receiver be easy to do to get rifles in 7mm Murray in the market? We already have a proven platform available in DI and Piston configurations so why not just expand the AR receivers and other components to run this caliber? It wouldn't weigh as much as an AR10 either.
 

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A normal AR-15 upper will not work. The bolt barrel extension will not handle it. As I said before if you want to et they smaller package then the AR-10s for this you cna use the MGI lower whihc has the magwell intended for the 308 that they can;t et to work and then use a Oly WSSM upper. The only dif in the upper is made to handle the bigger barrel extension. They already have a bolt that will work I think and if not they can be made by PTG but would need volume to offset cost. Not sure if MGI has released the mag well yet but I know they have it.
 

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DocGKR said:
Cris Murray has recently written:

"I've got factory made 7x46mm brass from Privi Partizan. Their brass is made straight from long 7.62x39 blank cartridge case they make and has the nice thick Russian rim, I want. Hopefully I'l be able to finish the pressure and powder tests this time, I'm trying to keep the speed at 2650 fps with a 130 gr projectile with pressure below 50K; all this out of a 16.5in barrel. Our last tests were good, but I need to document them with telemetry."

That is pretty amazing! I hope this cartridge does get off the ground... In my mind, the .270 British cartridge closer resembles the Murray round than the .280/30 at least externally, but both are very close in terms of performance. 7mm keeps coming up throughout cartridge design history... In law enforcement, they would call that a clue!

Best of luck to Mr. Murray...


I wonder what civilians will think of this cartridge. What I love about this forum is that this discussion is taking place... Other places would not be so friendly about it!
 

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Good & interesting info here....
I always like the Privi Partizan brass :shock: ...i got a good stock for all my Favrt Cal. and its cheap also
:)
i wonder how far the project will go...a nice bullet is a thing of beauty

178gr Amax&pvri 300WM
 

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They are the only Hrdy bullet I really like. The A-Max is a very nice bullet. I wish Hrdy would realize that and stop making every bullet other then this line with spire or secant noses.There are hell to tune unless you care seating jamming into the lands. The A-max is very easy to tune.
 
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