[deadduck357]

Mods please excuse if this is in the wrong forum, feel free to move, I am unfamiliar with this forum

Attached is a pdf for my 6.2mm OCC, would like some feedback

[Dr. Tad Hussein Winslow]

Needs some polish, but looks pretty sound. Need to add "full-auto controllability" in list of requirements.

I have long suspected that the "optimum" all-purpose combat round bullet diameter (a la 6.5 G and 6.8 S, etc.) should be either 6mm or .257, not 6.5mm or .277, for quantum leaps in bullet BC and SD, but yet with very little reduction in velocity (to maintain the bullet yawing result), and very little added to overall cartridge weight.

In other words, the optimum caliber (if there IS one better than 5.56x45) is much closer to the current 5.56 round than the current leading "contenders". 87 grains whizzing along past 2700 is gonna hurt, I guarantee ya, if you can actually obtain that!

The caliber should be .243 or .257, seems to me. The rest (case design) is nitpicking details, but it's obviously gonna be in the 40-45mm case length range, to fit in current platforms.

Does your parent case (the SAW) have less case taper than the chinese round, as it appears?

[AeroDillo]

The 6mm Chupacabra lives. :D

[mshootnit]

Amen brother. I think I posted a few years ago several times that the 6mm is it. You've really worked out what I have had rattling in my skull for awhile. Where can I buy one? You should have the rifle and 100 rounds of ammo made and shipped to the proving grounds.

[Maverick223]

I like it, but you need to call it the 6mm OCC...the 6.2mm is misleading and just about turned me off from the sound of it (lack of boolits). Also I think the 6.5Grendel will have you beat for LR trajectory...prove me wrong and the world will soon follow. :D

...and Welcome to THR! :)

[rangerruck]

with the bullet nose coming that close to the front of the mag, you are asking for probs; mainly from gi's in a hurry trying to load them, especially in combat situations, and messing them up, having them jam up, having the tighter clearances getting jammed up with debris, etc. etc.
Otherwise, I am all about a 6mm 70 to 80 grain bullet do 3k. what about the old Savage hipower, either the case or the bullet?

[deadduck357]

Dr. TAD, yes the taper is quite a bit less.

[deadduck357]

Ranger, Maximum COAL for a m16/AR-15 mag is 2.260", I have it loaded at 2.250" plenty room to spare.

[deadduck357]

Maveric, the .243 is 6.17mm, 6.2 is closer to correct than 6mm. Plus there are way to many 6mm cartridges out there, thought it may stand apart.

[Maverick223]

Maveric, the .243 is 6.17mm, 6.2 is closer to correct than 6mm. Plus there are way to many 6mm cartridges out there, thought it may stand apart.Right you are, but it sounds like a new boolit...which would be a problem. It may become a hangup with marketing.

What about external ballistics...I want numbers! :D

[JASmith]

Good start!

I think you're right -- the case capacity should be somewhat greater that that of the 6.8. Have you measured or calculated it? How much greater than for the 6.5 and 6.8?

The case capacity will give a slightly more quantitative indication of any ballistic advantage the 6.2 OCC might bring.

The marksman load should be compared the the Mk262 (77 gr Sierra Matchking).

What ballistic advantage does the new cartridge bring?

The Grendel yields impressive ballistics -- trajectory equal to or better that the 7.62 NATO, especially at long range. The OCC promises more powder, so might do even better in the 6.5.

-- Would be nice to get velocity and trajectory estimates for the OCC in 6.2, .25, and 6.5 bullets. The comparison would help cement selection of a particular caliber.

[Jaws]

Whenever there was scientific effort to find the ideal combat cartridge they always came to 6.8-7mm. 6.2mm won't make much difference to worth the change.

As a combat cartridge you need a bit of wiggle room in terms of terminal performance. You can't put all your eggs in one basket.
A larger caliber, heavier bullet will have good terminal performance even beyond fragmentation. You can't base all your killing on fragmentation. We know how things work with military bullets. The ones that fragments good, won't penetrate good and vice versa. That's why I think this days people place too much weight on fragmentation and speed.
The higher the speed, the more barrel wear you'll get.
I think what you have there is a good cartridge for civilians. For military I don't think you get much over the 5.56mm to justify a change. The 5.56 can use 75 gr. bullets already.
So far the best new military cartridge for AR15 is the 6.8Spc. It could have been a lot better but this is pretty much the best you could get out of the AR15.

In my opinion, the next military cartridge shouldn't be limited by the 40 year old rifle you are going to have to replace soon anyway.
Is like buying a processor, for your next computer, that has to work in the old computer you have to replace. You waste money and get very little in return.
Once in a while you need to bite the bullet, start from the scratch and build something from the ground up. Something that looks in the future, not something that brings over half the shortcomings of the old design.

Every attempt to get the "next combat cartridge" was wasted by the same AR15 mag/magwell. Both, 6.5 Grendel and 6.8 Spc, are not everything they could have been, because they had to work in the small AR15 magwell.

I'm looking forward to the 7x46mm Murray. He may release the full specs in a couple of months.:)

[Jaws]

the case capacity should be somewhat greater that that of the 6.8.

I don't think so. 6.8Spc. has thicker and longer case.

[deadduck357]

Jaws, how are you Quoting ? am I going blind caus I cant find a quote icon ?

But you are right my 6.2 OCC has less case capacity than the 6.8. But its not needed as its ballistics will exceed the 6.8spc. The 6.2 is pushing a lighter, smaller diameter bullet with better BC than the 6.8.

[Maverick223]

Jaws, how are you Quoting ? am I going blind caus I cant find a quote icon ?Like this. :neener:

It is the "cartoonish" text bubble icon at the top of the quick reply (or advanced reply).

:)

[deadduck357]

A larger caliber, heavier bullet will have good terminal performance even beyond fragmentation. You can't base all your killing on fragmentation. We know how things work with military bullets. The ones that fragments good, won't penetrate good and vice versa. That's why I think this days people place too much weight on fragmentation and speed.
The higher the speed, the more barrel wear you'll get.
I think what you have there is a good cartridge for civilians. For military I don't think you get much over the 5.56mm to justify a change. The 5.56 can use 75 gr. bullets already.

Once in a while you need to bite the bullet, start from the scratch and build something from the ground up. Something that looks in the future, not something that brings over half the shortcomings of the old design.

Every attempt to get the "next combat cartridge" was wasted by the same AR15 mag/magwell. Both, 6.5 Grendel and 6.8 Spc, are not everything they could have been, because they had to work in the small AR15 magwell.

.:)

Jaws, you are both right and wrong.

When we do go with a new platform then the selection of a new cartridge will be broader, but until then we are stuck within the limits at hand.

As for the military, they dont see it your way, I do, but no they dont. DOD has looked at the 6.8spc and decided against it mainly because of its poor velocity. The military likes/wants velocity. Some ammunition companies have tried to fix the 6.8 poor velocities by loading lighter bullets, yes it has increased its velocity but because of the diameter of the bullet its BC has gone to shyt. This is why I decided to go with a 6mm bullet, my ideal bullet would be 6.5mm if we had the option of a different platform. 6mm will produce good BC and velocity.

[deadduck357]

thanks Mav

[Maverick223]

Np, dd357.

:)

[Big_E]

Pretty impressed with the work you put into this.

One question, what bolt face does it use? (5.56? 6.8?) Because it looks like the base is a little larger than the 5.56.

[deadduck357]

Also I think the 6.5Grendel will have you beat for LR trajectory...prove me wrong and the world will soon follow. :D

...and Welcome to THR! :)

MAV223, I must have miss this, you are correct, but the 6.5Grendel was designed of a benchrest cartridge, it uses a modified benchrest case. The military will not go with it.

[deadduck357]

Pretty impressed with the work you put into this.

One question, what bolt face does it use? (5.56? 6.8?) Because it looks like the base is a little larger than the 5.56.

Bolts are easy to manufacture and cheap. Possible to just ream out a 5.56 bolt.

[JASmith]

Jaws, how are you Quoting ? am I going blind caus I cant find a quote icon ?

But you are right my 6.2 OCC has less case capacity than the 6.8. But its not needed as its ballistics will exceed the 6.8spc. The 6.2 is pushing a lighter, smaller diameter bullet with better BC than the 6.8.
What has been shown to date is a largely intiutive comparative assessment. The focus in justification appears to have largely been on the aesthetic and emotional - e. g., "more than," "smaller than," etc. In spite of this, things look interesting.

My technical side begs for numbers, e. g. "grains of water" compared with the alternatives, trajectory estimates, etc.

Moving to path forward:

The current acquisition standard is "capabiliites based," meaning that the new thing MUST fill an identified gap in military capabilities. The gap needs to be documented and justified.

An eternally frustrating part of capabilities based analyses that is demonstrating that the the gap can't be overcome by changes in tactics or other work-arounds.

So: Questions to be thinking about, but not necessarily posting are:

1. What capability gaps exist in infantry weapons that aren't already covered?

2. Can the proposed alternative fill in the gap at lower cost than the alternative or existing workarounds? (e. g., more liberal use of artillery, air-strikes, TOW, etc.)

[mshootnit]

I have nothing new to add except to address the thought that the 6mm is not enough bigger than the 5.56 to make a real difference in terms of terminal balistics. In reality there is a huge difference between the 22's and 24's in terminal balistics, and at not that much more of a weight. Here you have an effort to come up with a cartridge that is clearly better than the one in use now, which could be retrofitted into existing rifles with minimal cost. You can see it now in the middle east, M4 carbine equipped infantry are utilizing 77gr MK262 Mod1 ammo, hence the 1/7 twist but the velocity of this round is slow. The 5.56X45 case was never designed with that long of a bullet in mind. If you want to run it you should have a new case! Here you have the closest thing to a solution I have read yet.

[Maverick223]

...the 6.5Grendel was designed of a benchrest cartridge, it uses a modified benchrest case. The military will not go with it.I don't think the military really cares about the historical lineage of the cartridge...they use a varmint cartridge right now (not to suggest it is ineffective).

:)

[AeroDillo]

True. But how does a 6.5 fare with machine gun belt links?

[Maverick223]

True. But how does a 6.5 fare with machine gun belt links?True, I wasn't trying to suggest that the military would adopt 6.5G (or 6.8SPC), as I don't believe they will...just that the parent case isn't the issue.

:)

[AeroDillo]

I got you.

As for my response, there's a whole list of problems this thing address. I know - I've been hearing about the OCC for weeks now. I could probably recite most of the sales pitch in my sleep with a...reasonable degree of accuracy.

Plus, as long as I keep working with Deadduck he keeps buying me Mexican dinners. :D

[benzy2]

I think a 6mm bullet is the way to go when retrofitting current equipment. If starting from scratch I'm not so sure, but if we are trying to fit in a standard m16 type rifle I have always thought a 6mm would be the best option overall. For the relative maximum velocity you can get out of the m16 sized cases, the 6mm, to me, has always seemed like the best weight/diameter for the energy delivered. Good luck. I certainly have been looking at 6mm options for a while.

[deadduck357]

The 6mm is the optimal solution while working with the existing platform. If there were to be a new platform the caliber selection would be broader. My ideal caliber would be 6.5mm but this would require a longer case which we do not have the fortune. 6mm is ideal giving the restrictions, it gives you good weight + length = good BC.

[Jaws]

High BC bullets don't work that good at killing skiny enemy combatants. The longer the bullet, the more chance it will zip right trough the bad guy.

[Maverick223]

High BC bullets don't work that good at killing skiny enemy combatants. The longer the bullet, the more chance it will zip right trough the bad guy.How do you figure that?

:)

[deadduck357]

The military is finding that the 77gr is more effective than the 62gr. While my cartridge does have good BC its not the greatest, I do agree with you, I was not looking for the greatest BC, just good. Better BC would require a heavier 6mm projectile, say 100gr+, but this cartridge was not designed to be a benchrest round, so I tried to work in the medium. 100gr+ projectiles would diminish the performance, this is why I went with 75--90gr projectiles.

[OKLA Shooter]

Just an observation .. but all of this seems to be more simply necking down an existing cartridge case and slamming a 6mm bullet in it. A no-brainer. BTW and JFYI ( since you like acronyms :) ) Also, it is somewhat " naive " if not and/or " arrogant" to call an unfired, untested " round " .. the " optimum combat cartridge " when it has never even been fired from a test barrel .. or worse, never been tested by the military or used in combat! I'm sure military experts and/or real veterans would enjoy that unjustified optimism. :) However, there seems to be quite a bit of " plagarism " in the accummulated information, and, lacking in theory from true ballistics testing. Where is the accurate information on interior and exterior ballistics that pertains to; chamber pressures, headspace, throat erosion on test barrels, if any... velocity, energy, trajectory, penetration,expansion, comparative ballistic coefficients, sectional density, wind vector-wind drift at varying distances, effects of barometric pressure, altitude, temperature .. on and on ... that would justify even remotely calling this " unknown " cartridge the " optimum combat cartridge" ? Doesn't come across with much merit to call a cartridge " optimal " that has not been tried and tested.

Maverick is right on one thing. Numerically and mathematically a 6.2mm is a 6mm ! Maybe the developer doesn't know, but, anything between 6.0 and 6.999999999 is a 6mm. We don't say we have ten and half cents do we ? We say we have 10 cents .. same concept numerically. So, no need to quibble over a cartridge that is significantly 6.2mm or 6.258mm .. right ? I mean, there is this thing called " infinity " in numbers. Pi is the ratio of the circumference of a circle to its diameter= 3.14159265358979323846. ... and it repeats itself .. as do most measurements, if you want to be scientifically exact and precise.

1. It is expensive to correctly manufacture a mold, even in small quantities ( or machine from metal ) even something as simple as a key chain !

2. Does the developer have any combat experience or combat training in a military unit in his background ? Does he shoot .. or .. just like to " talk about shooting " .

3. Is he a mechanical engineer or a trained ballistics technician ?

4. Is he a distinguished shooter ( one who through " experience " has achieved success, reward or award ) ?

5. Has he discussed with combat and military veterans the effects of past and present military rounds in combat ?

6 Seems like the developer has never reloaded or target level reloaded for benchrest shooting. You can't seat a bullet in the case neck anywhere you want to just to reach a " convenient " overall cartridge length. There are parameters for bullet seating depth. ( if you seat it too deep, it can just fall into the case, as an extreme example ! )

Remember .... there is a world of difference between an " authority " and a " self-proclaimed " authority. The self proclaimed authority only has himself/herself to justify that authority . Most authorities have true experience and training , or , PROVEN ability that justifies them being called an " authority " ... by others . There are no shortcuts.

[mshootnit]

Does the developer have any combat experience or combat training in a military unit in his background ? Does he shoot .. or .. just like to " talk about shooting " .

Did Bell have alot of experience using telephones before he invented one? Did the Wright brothers have a lot of flight time when they drew up the first airplane?

[benzy2]

"Numerically and mathematically a 6.2mm is a 6mm ! Maybe the developer doesn't know, but, anything between 6.0 and 6.999999999 is a 6mm. We don't say we have ten and half cents do we ? We say we have 10 cents .. same concept numerically. So, no need to quibble over a cartridge that is significantly 6.2mm or 6.258mm .. right ?"

So then what do you call a 6.5mm bullet? Do you call them 6mm. What about 6.8mm bullets? Call them 6mm as well? What about 7mm, 7.62, and 7.7? While I do see your point that a 6.2 is accepted as a 6mm, the part about everything from 6.0 to 6.9999... isn't correct and isn't accepted by the shooting community. While we may not have 10 and a half cents we certainly have ten and a half dollars.

[Maverick223]

Maverick is right on one thing. Numerically and mathematically a 6.2mm is a 6mm !Not really what I meant, what I was referring to is that the "6.2mm" is pretty much globally recognized as a 6mm (or alternatively .243cal). OTOH 6.99∞mm ≠ 6mm.

Also, I think you were a bit harsh to the OP, that has a pretty decent idea IMO; especially considering it is your initial post here at THR.

:)

[OKLA Shooter]

Benzy .... abstract, I was talking about the " categories " of rounds .. 5mm,6mm,7mm,8mm,9mm. Uh, .. 6.9999 is a 6mm back when I was in college.

MNoShoot .... Alexander Graham Bell didn't take his untried, untested phone to a Verizon center with tried and tested modern technology and say " this is the optimum civilian telephone". The Wright Brothers would be considered morons if they took the Kitty Hawk to an air show today and said " this is the optimum combat fighter " . This is 2010 .. not 1905. You see, in their time .. it was the " only " phone and " only " airplane !

It amazes me that many on these forums don't understand how the military operates. And, I can tell from the comments on this forum that many don't .

This suggestion of " optimum " combat cartridge, ( after many weapons have served in past and present wars. e.g. M1Garand, M1 Carbine, M14, M-16 ) ..untested .. without specs .. never having been fired from a test rifle, without specs .., is like you building a car in your backyard without wheels on it yet and saying " this is the fastest car in the world " .

Good luck ...:)

[Maverick223]

6.9999 is a 6mm back when I was in college.Not a math major were you?...accounting miscounting perhaps? :neener:

[mshootnit]

2 posts and he is already calling folks names.

[deadduck357]

WOW, haven't been here in a while,WOW.

Looks like someone targeted my thread, joined THR and replied to this thread 2 times all in the same day. Hrmmm. Makes ya wonder.

Thanks to mshootnit, benzy2 & Maverick223

I never once stated I was an "authority". Be more thorough.

As for your problem with 'Optimum', again you should be more thorough.

Merriam-Webster - Optimum: Greatest degree attained or attainable under
implied or specified conditions.

If OCC offends, just call it 6.2 OCC (Optimum Chupacabra Cartridge).

[Maverick223]

NP deadduck, good luck on the project.

:)

[praharin]

At least it has a cool name. I'll be following this, as I am looking for an AR15 in a harder hitting caliber for 300-400 yards max. 6.8 has been the winner so far, but if the 6.2 performs as you say it will, i'll try to keep an eye on it.

If it works out, I may have to build one in a CZ 527 platform also.

[longdayjake]

I personally find this idea to be a FAIL.

Why?

1. The BC numbers presented don't beat that of the 6.8 bullet.
2. Requiring light bullets to go at high velocity is basically what we are doing right now with the 5.56.
3. The ability to use much heavier bullets in the 6.8 and 6.5 increases the amount of energy deposited on target.
4. The higher weight and bc bullets of the 6.5 help it to maintain killing power out to a much longer range even at lower velocities.
5. The 6.8 spcII has been achieving the higher velocities that the military dropped the spcI for not obtaining.
6. Velocity is not the only factor behind terminal performance.
7. I doubt that with less powder capacity you are going to get a 75 grain bullet to go much faster than an 85 grain bullet from the 6.8 with more powder capacity.
8. Because the 6mm bullet is longer it would require a faster twist rate to stabalize it. The faster twist rate of the spcI was known to dramatically reduce initial velocity.
9. Because the 6mm bullet is longer it will suffer from the same limitations of the 6.5 grendel. It will have more surface area on the body requiring more pressure to push them out at the same velocity of the 6.8 bullets. You will reach your pressure limit before you can reach your velocity goal.

I think its time to admit that the real following behind any ar intermediate cartridge is all based on the bullet itself.

Those that love the .270 will go with the 6.8
Those that love the .264 will go with the 6.5
Those that love their 6mms will like your idea.

Seriously though, all of you guys that said you liked this idea probably have a .243 in their safe right?

[praharin]

a 243 Win won't fit in a standard AR15 action though

[Maverick223]

Seriously though, all of you guys that said you liked this idea probably have a .243 in their safe right?No, not a big fan of the .243Win, or most other 6mm due to overbore/short bbl life. I generally prefer a 6.5/7mm, but do not care for the .270/6.8mm that much. That said, I feel that the caliber should be matched to the case capacity. .22s work well in a .223Rem./5.56NATO case size, 6.5mm is good for a .308 case size (.260Rem.), 7mm is good in a .30-06 case size (.280Rem.), and .30cal is well suited to a magnum case (.300WM), anything over .338cal needs to be underbore to be controllable, but that is acceptable for the applications that it is suited for. Personally I believe that the "6.2mmOCC" has a good caliber/capacity relationship so I rather like the idea (though I prefer the 6.5Grendel for civilian use).

:)

[deadduck357]

No, not a big fan of the .243Win, or most other 6mm due to overbore/short bbl life. I generally prefer a 6.5/7mm, but do not care for the .270/6.8mm that much. That said, I feel that the caliber should be matched to the case capacity. .22s work well in a .223Rem./5.56NATO case size, 6.5mm is good for a .308 case size (.260Rem.), 7mm is good in a .30-06 case size (.280Rem.), and .30cal is well suited to a magnum case (.300WM), anything over .338cal needs to be underbore to be controllable, but that is acceptable for the applications that it is suited for. Personally I believe that the "6.2mmOCC" has a good caliber/capacity relationship so I rather like the idea (though I prefer the 6.5Grendel for civilian use).

:)

How are you doing that, reading my mind, thats just not right.

[Maverick223]

How are you doing that, reading my mind, thats just not right.I didn't read your mind I hacked into your computer. :uhoh: :neener:

[deadduck357]

1. The BC numbers presented don't beat that of the 6.8 bullet.
2. Requiring light bullets to go at high velocity is basically what we are doing right now with the 5.56.
3. The ability to use much heavier bullets in the 6.8 and 6.5 increases the amount of energy deposited on target.
4. The higher weight and bc bullets of the 6.5 help it to maintain killing power out to a much longer range even at lower velocities.
5. The 6.8 spcII has been achieving the higher velocities that the military dropped the spcI for not obtaining.
6. Velocity is not the only factor behind terminal performance.
7. I doubt that with less powder capacity you are going to get a 75 grain bullet to go much faster than an 85 grain bullet from the 6.8 with more powder capacity.
8. Because the 6mm bullet is longer it would require a faster twist rate to stabalize it. The faster twist rate of the spcI was known to dramatically reduce initial velocity.
9. Because the 6mm bullet is longer it will suffer from the same limitations of the 6.5 grendel. It will have more surface area on the body requiring more pressure to push them out at the same velocity of the 6.8 bullets. You will reach your pressure limit before you can reach your velocity goal.



Much of what you say is true, BUT at a LOSS of magazine capacity and mediocre velocities.

2) Military rounds have increased in weight. 55gr to 62gr and now 75 - 77gr.

7) I wouldn't compare the .277 85gr to a 75gr 6mm, the 75gr 6mm smokes the .277 85gr in BC. Heck, .224 55gr has the same BC as the .277 85gr. Might as well stick with the same old thing then. For the 6.8 to achieve velocities needed it requires such light projectiles that its BC has gone down the toilet.

8) I have no idea what your trying to get at with that ?

9) Same as #8 ?

Never have owned a .243win. in my life.

[deadduck357]

I didn't read your mind I hacked into your computer. :uhoh: :neener:

You SOB :D

[deadduck357]

I understand that most would use 6mm to designate a .243" bullet, But a 5.56mm is not really 5.56mm it's 5.6896, so it's closer to 5.7mm. .223rem is .224". This could go on and on and on. So 6.17mm = 6.2mm :confused:

[Maverick223]

I understand that most would use 6mm to designate a .243" bullet, But a 5.56mm is not really 5.56mm it's 5.6896, so it's closer to 5.7mm. .223rem is .224". This could go on and on and on. So 6.17mm = 6.2mm...but, the cartridge caliber designation is typically based upon the bore diameter which in the case of .223Rem./5.56NATO is actually pretty close to 5.56mm so that makes sense (at least to me). Same with many others such as .45cal. pistols and rifles, both have a approximately .450in. bore, though they shoot .452in. and .458in. projectiles respectively. In short there is no well accepted naming convention, but by military standards the bore is often the basis for the cartridge designation.

Fully confused yet? http://forums.nitroexpress.com/images/graemlins/smilies/general/confused.gif

[deadduck357]

Did everyone give the 5.7x28mm hell also for not calling it 5.56x28mm ?

It is very confusing when you dig into it.

.223 is really .224 and its 5.6896(5.7) not 5.56mm ?
.257 is really not 6.35, it's 6.5mm?
.264 is really not 6.5, it's 6.7mm?
.277 is really not 6.8, it's 7mm ?
.284 is really not 7mm, its 7.2mm?

[Maverick223]

Did everyone give the 5.7x28mm hell also for not calling it 5.56x28mm?No, I think they gave that hell, for having performance roughly equal to that of a .22WMR rifle. Haven't gotten around to how bad they named it. :D

It is very confusing when you dig into it.Yep. :)

[deadduck357]

I don't think that I have posted this yet. I sent one of my 6.2mm OCC prototypes to Superior Shooting Systems Inc. a few weeks back to run figures and measurements. I have been informed that David Tubb likes it and they are going to try and get brass produced for it, we'll see. I am curious to see what figures(ballistics) they come up with.

[Maverick223]

Congrats on your success, hopefully there will be additional good news to follow. http://forums.nitroexpress.com/images/graemlins/smilies/general/xyxthumbs.gif

[deadduck357]

We'll see. I figured they would know alot about the 6mm and could work with the development. Also figured they would have more pull in getting a brass manufacturer to produce some brass. Will see.

[deadduck357]

I talked with SSS inc. today and it has been sent to Silver State Armory.

[Maverick223]

Yep, not doubt he will soon be forgotten...Art will come along and banish him. :D

[longdayjake]

Here are some ballistics figures just to give an idea on how this will compare to the 6.8 and 6.5.

First, your 75 grain bullet with a claimed bc of .330 out to 600 yards starting at 3000fps.

Range Velocity Impact Drop ToF Energy Drift
0 3000 0 0 0 1499 0
25 2919 0.39 0.18 0.03 1419 0
50 2847 0.53 0.61 0.05 1350 0
75 2776 0.41 1.3 0.08 1283 0
100 2706 0 2.28 0.11 1219 0
125 2637 -0.7 3.56 0.14 1158 0
150 2569 -1.72 5.15 0.16 1099 0
175 2503 -3.08 7.08 0.19 1043 0
200 2437 -4.78 9.35 0.22 989 0
225 2373 -6.85 11.99 0.26 938 0
250 2310 -9.3 15.01 0.29 889 0
275 2248 -12.17 18.45 0.32 842 0
300 2186 -15.46 22.31 0.35 796 0
325 2126 -19.21 26.63 0.39 753 0
350 2066 -23.45 31.44 0.43 711 0
375 2007 -28.18 36.75 0.46 671 0
400 1950 -33.46 42.6 0.5 633 0
425 1893 -39.32 49.03 0.54 597 0
450 1838 -45.79 56.07 0.58 563 0
475 1784 -52.89 63.74 0.62 530 0
500 1731 -60.68 72.1 0.66 499 0
525 1679 -69.2 81.19 0.71 469 0
550 1629 -78.49 91.05 0.75 442 0
575 1579 -88.6 101.73 0.8 415 0
600 1532 -99.58 113.28 0.85 391 0

Okay, now a 110 grain bullet from a 6.8 going at 2600 fps with a bc of .32

Range Velocity Impact Drop ToF Energy Drift
0 2600 0 0 0 1651 0
25 2525 0.52 0.23 0.03 1557 0
50 2457 0.72 0.79 0.06 1475 0
75 2390 0.55 1.71 0.09 1395 0
100 2325 0 3.02 0.12 1320 0
125 2261 -0.96 4.73 0.16 1249 0
150 2197 -2.34 6.87 0.19 1179 0
175 2135 -4.18 9.46 0.23 1113 0
200 2073 -6.48 12.52 0.26 1050 0
225 2012 -9.31 16.1 0.3 989 0
250 1953 -12.66 20.21 0.34 932 0
275 1895 -16.59 24.89 0.37 877 0
300 1837 -21.12 30.18 0.42 824 0
325 1782 -26.31 36.12 0.46 776 0
350 1727 -32.17 42.74 0.5 729 0
375 1674 -38.77 50.09 0.54 684 0
400 1622 -46.14 58.22 0.59 643 0
425 1571 -54.35 67.18 0.64 603 0
450 1522 -63.42 77.01 0.68 566 0
475 1475 -73.44 87.78 0.73 531 0
500 1429 -84.45 99.55 0.79 499 0
525 1386 -96.54 112.39 0.84 469 0
550 1344 -109.74 126.35 0.89 441 0
575 1305 -124.16 141.52 0.95 416 0
600 1267 -139.83 157.95 1.01 392 0

Your cartridge never beats the 6.8 in energy at all even with an advantage of 400 fps!!!


And now a 123 grain bullet from the 6.5 grendel with a BC of .55 shot at 2500

Range Velocity Impact Drop ToF Energy Drift
0 2500 0 0 0 1707 0
25 2458 0.55 0.24 0.03 1650 0
50 2419 0.74 0.84 0.06 1598 0
75 2381 0.56 1.81 0.09 1548 0
100 2343 0 3.16 0.13 1499 0
125 2305 -0.96 4.91 0.16 1451 0
150 2268 -2.34 7.08 0.19 1405 0
175 2231 -4.14 9.67 0.22 1359 0
200 2195 -6.37 12.69 0.26 1316 0
225 2158 -9.06 16.17 0.29 1272 0
250 2122 -12.21 20.12 0.33 1230 0
275 2087 -15.85 24.55 0.36 1190 0
300 2052 -19.99 29.48 0.4 1150 0
325 2017 -24.65 34.93 0.44 1111 0
350 1982 -29.84 40.91 0.47 1073 0
375 1948 -35.59 47.45 0.51 1036 0
400 1914 -41.91 54.56 0.55 1001 0
425 1881 -48.83 62.27 0.59 966 0
450 1848 -56.36 70.59 0.63 933 0
475 1816 -64.53 79.55 0.67 901 0
500 1783 -73.35 89.16 0.71 868 0
525 1752 -82.87 99.47 0.76 838 0
550 1721 -93.08 110.47 0.8 809 0
575 1690 -104.04 122.22 0.84 780 0
600 1660 -115.75 134.72 0.89 753 0

As you can see the 123 grain bullet from the grendel beats the heck out of both of them for range, energy, and trajectory.

Now, why dont you just take the .223 casing and put a 6mm bullet in it? Cause its already been done!!!!! How much more powder capacity does the new casing give you? Looking at the dimensions, it probably wont get you any more at all. Sorry, but your idea would take way too much work to get it to perform the same as the 6mmx45.

[longdayjake]

Sorry if I sound like a jerk, but I just don't see an advantage to this cartride.

[ronbuick]

How can anyone improve or try to improve on an item, in this case a 5.56 to try and make it better, maybe it will or maybe not, but if a person has a dream to do something
like this you should not be knocking him, you ought to be applauding this person, you should give him your support instead of all your negative waves Moriarity.

Ron

[Maverick223]

Sorry if I sound like a jerk, but I just don't see an advantage to this cartridge.I somewhat feel the same way...however my desires (in a cartridge), and the needs of the military are two different things. I believe this may be a winner for general military use, while I would prefer a 6.5Grendel to meet my needs (in an AR-15 platform anyway). You see this as what can it do that the 6.5/6.8 can't (which is little), but it has some nice advantages such as approximating the speed of the 6.5Grendel, and the energy of the 6.8SPC, while doing so with less powder, less weight, smaller size (greater magazine capacity), and less drop at combat ranges.

It suits the role pretty well, I think the biggest hurdle is that the 5.56NATO does a reasonably good job...so why replace it at a fairly great cost? I think this would be a great option if (and when) we decide to replace the current M4, but until then I don't believe that the brass will be open to any cartridge.

:)

[Jaws]

I think this would be a great option if (and when) we decide to replace the current M4, but until then I don't believe that the brass will be open to any cartridge.

Nah. 70-75gr just doesn't cut it. You need a bigger chunk of metal.:D Just enough is not always enough.:D
The designer of the 6.8Spc, Mr Cris Murray just posted the specs for his 7x46mm UIAC. Case and chamber drawings and some specs.

http://cid-4e0b456cafea6a74.skydrive.live.com/browse.aspx/.res/4E0B456CAFEA6A74!147

That's a cartridge worth switching to. It could do the job of both 5.56 and 7.62NATO with one cartridge.
No strings attatched to the old platform. Designed from the ground up to combine both worlds in one package.
Basically, the 7.62x39mm Russian case extended to 46mm and necked down to 7mm. Pushing a 130gr, .411BC, projectile at 2650fps from 16.5" barrel. Plenty energy across the whole range and maximized terminal performance.:)
You would never feel outgunned again. :evil:

[Maverick223]

I have to say that 7mm sounds pretty tasty too...I would love to see the numbers (may have been in the link, but it didn't work for me).

:)

[Jaws]

You have there links to two .pdf and one power point docs. If you click for example on "7x46mmUIAC DOC1", a new page opens and you have on the left the "download" link. Is a pdf that contains case and chamber specs.

Here's some stuf on in those docs:



"The 7x46mm was designed as a single replacement for our current two cartridge system.
1. The 7x46mm UIAC is
a. Designed to used a 8,4 g. (130 gr.) FMJ projectile having a length of 28.5mm (1.1220 in.), having a BC of .411 or better.
b. Maximum cartridge over-all-length (AOL) 64.262mm (2.530 in.)
f. Designed for 7mm Mauser bore diameters of 6,98mm bore, 7,24mm groove, having 4 grooves at a 1:297mm (1:11 in.) twist rate.
g. Can be used in 7mm American bore diameters of 7,04mm bore, 7,21mm groove provided proper reamer bushings are used.
2. Pressure specifications of the 7x46mm UIAC are the same as 7.61x51mm NATO/EPVAT
a. Maximum Service Pressure (Pmax) 4150 bar (60,190 psi)
b. Peak Maximum Service Pressure (PK) 4772 bar (69,218.5 psi) Pmax + 15%
c. Proof Pressure (PE) 5190 bar (75,275 psi) PK + 25%



7x46mm UIAC

Sight Height: 1.5 inches Bullet Ballistic Coef.: .411
Target Range: 500 yards Muzzle Velocity: 2650 fps
Altitude: 500 feet Bullet Weight: 130 grains
Temperature: 50 Fahrenheit

http://img.photobucket.com/albums/v258/<FA>Jaws/7x46mm0.jpg

http://img.photobucket.com/albums/v258/<FA>Jaws/7x46mm2.jpg

http://img.photobucket.com/albums/v258/<FA>Jaws/7x46mm4.jpg

http://img.photobucket.com/albums/v258/<FA>Jaws/7x46mm1.jpg"

[JShirley]

Guys, if someone isn't fitting in with the polite culture we should have here, don't descend to their level. Don't call any names, just hit "report post" icon, and please be the example of what The High Road means.

Thanks,

John

[ronbuick]

One must remember how much ammo one can carry with them, lite weight is good, ala
5.56, this 6.2 appears to pack quite a punch both in close and at distance, but do not know what would be comfortable amount to carrry, it also seems to fit in existing mags
as well, so just changing out the upper is all their is, cost would be down as well, pluw the number that would come on the open market, just some thinking going on here.

Ron

[Jaws]

I don't know how well will fit in 5.56 mags. Remember, 6.8SPC and 6.5 grendel suposed to work flawlesly in regular AR mags.

[Maverick223]

Remember, 6.8SPC and 6.5 grendel suposed to work flawlesly in regular AR mags.Huh? If that is the case there are a lot of unnecessary and [comparatively] expensive magazines that are specifically designed for the aforementioned cartridges (and the only cartridge that I can think of that doesn't is the .458SOCOM). I don't think that designing a new magazine would be a big hurdle, heck you already have to swap the bolt and bbl.

:)

[deadduck357]

Now, why dont you just take the .223 casing and put a 6mm bullet in it? Cause its already been done!!!!! How much more powder capacity does the new casing give you? Looking at the dimensions, it probably wont get you any more at all. Sorry, but your idea would take way too much work to get it to perform the same as the 6mmx45.

I think Mav mentioned this, Magazine advantage goes to the 6.2mm. As I have stated I'm not comparing the 6.2 to the 6.5g or 6.8spc for the purpose that they will not be adopted by the military.

[deadduck357]

Nah. 70-75gr just doesn't cut it. You need a bigger chunk of metal.:D Just enough is not always enough.:D
The designer of the 6.8Spc, Mr Cris Murray just posted the specs for his 7x46mm UIAC. Case and chamber drawings and some specs.

http://cid-4e0b456cafea6a74.skydrive.live.com/browse.aspx/.res/4E0B456CAFEA6A74!147

That's a cartridge worth switching to. It could do the job of both 5.56 and 7.62NATO with one cartridge.
No strings attatched to the old platform. Designed from the ground up to combine both worlds in one package.
Basically, the 7.62x39mm Russian case extended to 46mm and necked down to 7mm. Pushing a 130gr, .411BC, projectile at 2650fps from 16.5" barrel. Plenty energy across the whole range and maximized terminal performance.:)
You would never feel outgunned again. :evil:

Case diameter is even larger than the 6.8spc,way less magazine capacity.

+Also more recoil, especially in full auto

[deadduck357]

It suits the role pretty well, I think the biggest hurdle is that the 5.56NATO does a reasonably good job...so why replace it at a fairly great cost? I think this would be a great option if (and when) we decide to replace the current M4, but until then I don't believe that the brass will be open to any cartridge.

:)

I don't know if you saw one of my previous posts, Superior Shooting Systems Inc. has sent the 6.2mm OCC to Silver State Armory for a work-up.

While talking to SSS they mentioned that the 6.2mm would have to be thoroughly tested and then would have to go through SpecOps in field before any considerations would be made.

[Jaws]

I don't see people carrying AK's complaining about mag capacity. 7x46mm uses the same brass just longer.:) About recoil I don't know. I shot few years ago an old czech rifle chambered in 7.62x45mm (130gr. bullet) and recoil was surprisingly mild. That was originaly proposed as base case for 7x46UIAC. Just necked down to 7mm.

[Jaws]

Huh? If that is the case there are a lot of unnecessary and [comparatively] expensive magazines that are specifically designed for the aforementioned cartridges (and the only cartridge that I can think of that doesn't is the .458SOCOM). I don't think that designing a new magazine would be a big hurdle, heck you already have to swap the bolt and bbl.



I was just joking.:) That's how they were advertized first. Of course they didn't quite work from regular 5.56 mags.

[deadduck357]

One must remember how much ammo one can carry with them, lite weight is good, ala
5.56, this 6.2 appears to pack quite a punch both in close and at distance, but do not know what would be comfortable amount to carrry, it also seems to fit in existing mags
as well, so just changing out the upper is all their is, cost would be down as well, pluw the number that would come on the open market, just some thinking going on here.

Ron

I agree with you about weight and quantity.

But it is not know if there will be a cartridge binding problem with the 6.2mm OCC. I only stated that the 6.2mm properly engage the feed lips of AR15/M16 mags. I only have a few prototypes, not 28-30 rounds to test. Blanks would have to be run to test.

[deadduck357]

I was just joking.:) That's how they were advertized first. Of course they didn't quite work from regular 5.56 mags.

I remember that also, shame on them. I'm not saying it will, it needs to be tested.

But the 6.8spc almost worked, the diameter was just a little to much. The interior bevels on the standard AR15/M16 mag had to be altered a little.

Now, if the 6.8spc almost worked but was a little to big and the 6.2 case is smaller in diameter than the 6.8 ???

[deadduck357]

I don't see people carrying AK's complaining about mag capacity. 7x46mm uses the same brass just longer.:) About recoil I don't know. I shot few years ago an old czech rifle chambered in 7.62x45mm (130gr. bullet) and recoil was surprisingly mild. That was originaly proposed as base case for 7x46UIAC. Just necked down to 7mm.

"People" = U.S. Military ? NO. Some Spec Ops ? Yes.

[Jaws]

I'm talking about the millions that carry AK47. The basic AK has 30 rounds. I don't see the problem with that mag.

Remember, 7x46 is not made for the AR15. Ar15 mag lenght is not important.

[deadduck357]

Nah. 70-75gr just doesn't cut it. You need a bigger chunk of metal.:D Just enough is not always enough.:D


You may be right. I was looking for velocity.

I was informed by SSS Friday that David Tubb said that a 90gr. would be the weight to go with because of its SD.

Could you explain why ?

[deadduck357]

I'm talking about the millions that carry AK47. The basic AK has 30 rounds. I don't see the problem with that mag.

Remember, 7x46 is not made for the AR15. Ar15 mag lenght is not important.

So, then it would require a completely new platform. Your getting us way off base here. The 6.2mm was designed for the AR15/M16.

[Maverick223]

I don't know if you saw one of my previous posts, Superior Shooting Systems Inc. has sent the 6.2mm OCC to Silver State Armory for a work-up.

While talking to SSS they mentioned that the 6.2mm would have to be thoroughly tested and then would have to go through SpecOps in field before any considerations would be made.I did, I just don't believe that the brass are willing to change cartridges at this point. Don't get me wrong, I think you have a good idea, and I wouldn't abandon it, but I think it will be quite a while before it is considered for adoption.

:)

[deadduck357]

I agree, not while they are stuck in the sand. But maybe some spec ops could run it.

[longdayjake]

Okay, tell me one more time what this cartridge can do that the 5.56 cannot. I read your little pdf on it and it is not quite clear to me.

[deadduck357]

longdayjake, could you run some figures ? 28gr. of IMR 8208 XBR with a Berger 6mm 90gr. MT BT (.411 BC) , Thanks

[deadduck357]

Also how about, same powder with the 6mm/.243 Lapua 90gr. Scenar (BC .420 )? Thanks

[Maverick223]

Will it accommodate (and maintain good ballistics) a 95gr. SMK. If so I would think that would be the ticket, as it has a very high BC (0.480).

:)

[deadduck357]

I have played with the 95gr SMK some and yes it will work but it does start to get back in the case some, also wondering how it would effect velocity.

[deadduck357]

Both Sierra and Lapua have a 90gr FMJBT with BC .387 and SD .218

While not as good as the Berger 90gr MT BT or Lapua 90gr Scenar it would make for a good FMJ round.

[longdayjake]

longdayjake, could you run some figures ? 28gr. of IMR 8208 XBR with a Berger 6mm 90gr. MT BT (.411 BC) , Thanks

Can your casing fit that many grains of powder and still have room for the projectile? It looks to me like it wouldn't have any more case capacity than the .223. Couple that with the longer bullets and you get even less powder capacity than the .223. I am unsure how to run those numbers since the casing doesn't really exist in any program that you can run.

[deadduck357]

Powder charge for the 6mm SAW was 28 grains with a 105gr projectile. The 90gr Sierra FMJBT, 87gr Hornady HPBT, 85gr Sierra BTHP do not impede case capacity. The 90gr Berger and Lapua do impede beyond the neck some, within a couple mm's. Just trying to get a rough estimate on figures till I get reports back from SSS and SSA. Could you somehow work up some rough figures ?

[longdayjake]

without knowing the pressures one could only guess. My personal guess is that with only 28 grains of powder you will probably get around 2700-2800 fps. You aren't going to get that much more velocity from the saw case just because you lightened the bullet by a few grains. Maybe 200-300 fps more. I would like to be wrong but my experience has always shown this to be true.

[deadduck357]

LDJ, original chamber pressure of the 6mm SAW was 47,700psi. How much velocity could be gained by jumping it up to 50,000 or 52,000psi ?

[longdayjake]

I couldn't say. You might try buying quickload and finding out that way.

[Bins16]

I know this might be a random bump, but I am interested in this, any news? Also, about how much KE is this putting out?

[JASmith]

I'm amazed at how time flies -- it's been two years since we had that very interesting discussion!

I'm hoping that deadduck357 was able to scare up dies and barrel so that he could get some experimental results. The timing is about right for him to report out if everything went well.

I know that wildcatting can use up a lot of calendar time -- I just passed the one year mark with an unrelated project. Dies, reamer, and so on are built. The barrel should be ready within two weeks. I have had one hiccup in the dies -- so will need to get an intermediate forming die to neck the brass down to the smaller caliber. I won't know if everything else will come together until the barrel comes in, gets mounted on the rifle and we do the first shots. Only then do we get to find out if the cartridge works as hoped. I'm looking at the beter part of another year before I can draw solid conclusions.

So, it is possible that his components and test campaign haven't come together yet.

Another major factor is the winding down of the current conflict is dampening excitement over new and better military cartridges.