6.2mm OCC

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mattsbox99

Hunter
Joined
Jan 12, 2009
Messages
3,391
Our military is pretty broke to retool for so many new guns, although it seems a good venture. I like the 6.8 SPC, I'd really like a .257 SPC though.
 

picketpin

Buckeye
Joined
Jun 29, 2006
Messages
1,544
There is very very little new in the reloading/cartridge world.

You have done a lot of research and thinking and I appaud that.

A couple of "comments":

Ergonomic: (def) Especially refering to the work place, designed to provide optimum comfort and avoid stress or injury. I'm not sure of your intened use of the word when it comes to cartridge design???

Why such a long neck on your design? Once you have at least one caliber of length you usually have sufficient bullet grip, especially with a military bullet with a cannlure. You could cut the neck length in half and increase the case capacity significantly.

If I were going to use a 6mm as quick look shows that the .224 Weatherby necked to .243 as is will drive a 100 grain 6mm to 3000 fps.
That's without the modern ball powders or any other newer powders since the 50s.

The case has some issues but none that can't be solved. There is no reason for the belt, it was/is a marketing tool. There is no reason for the radiused shoulder, it to is/was a marketing tool and really does none of the things that Weatherby originally claimed for it. It would be simple to simply use a 28 degree or better a 40 degree shoulder.

The case capacity as is is a full 25% greater than the .223 in it's military version. The .223 holds 31 grains of ball powder and the .224 holds 41 grains. As a quick comparison the .223 will drive a 60 grain bullet 3100 fps but a .224 WBY will drive the same bullet to 3600 fps.

The odd case head size on the Weatherby will actually fit the bolt face of a AR15/M16 but if it's an issue it could simply use the standard .223 head size with a rebate.

If shortening the case to achieve the correct AOL to work in a magazine reduces the case capacity to where to desired 3000 fps with a 100/105 grain bullet is lost one could simply form the case with nearly straight walls and take a bit of the taper out and replace the lost case capacity grain for grain.

The increase in case diameter of .039 inches would reduce the magazine capacity as it exists by one round. One could probably design a spring or follower that would negate that as an issue.

Like I said there isn't much new.

It's sort of like the short mags for all the hoopla, most were designed about 40 years ago in one form or another.

It is fun though to play with this stuff and design cartridges.

Many years ago in my teens I spent a lot of time designing a new 22 centerfire based on the 257 Roberts case. Mostly because I hunted with a Roberts. I got it designed and figured out and sent my drawings to Clymer to make a reamer along with a check. They were really nice when they called and asked if I "really " wanted them to produce the reamer for my 22-4000? Why not, is there a problem? No , but is seems that except for the difference of a .224 bullet versus a .228 bullet, you have reinvented the 22 Newton!! I bought a 220 Swift. ;-0

The best and have fun, that's what it's all about.

Of course I personally think the should have used/accepted the 222 Mag in the Armalite rather than the .223 in the M16 to start with. Better rifle, better cartridge design, higher velocity.

Ross
 

deadduck357

Single-Sixer
Joined
Jul 2, 2007
Messages
404
picketpin":1rwwbb1y said:
There is very very little new in the reloading/cartridge world.

You have done a lot of research and thinking and I appaud that.

A couple of "comments":

Ergonomic: (def) Especially refering to the work place, designed to provide optimum comfort and avoid stress or injury. I'm not sure of your intened use of the word when it comes to cartridge design???

Why such a long neck on your design? Once you have at least one caliber of length you usually have sufficient bullet grip, especially with a military bullet with a cannlure. You could cut the neck length in half and increase the case capacity significantly.

If I were going to use a 6mm as quick look shows that the .224 Weatherby necked to .243 as is will drive a 100 grain 6mm to 3000 fps.
That's without the modern ball powders or any other newer powders since the 50s.

The case has some issues but none that can't be solved. There is no reason for the belt, it was/is a marketing tool. There is no reason for the radiused shoulder, it to is/was a marketing tool and really does none of the things that Weatherby originally claimed for it. It would be simple to simply use a 28 degree or better a 40 degree shoulder.

The case capacity as is is a full 25% greater than the .223 in it's military version. The .223 holds 31 grains of ball powder and the .224 holds 41 grains. As a quick comparison the .223 will drive a 60 grain bullet 3100 fps but a .224 WBY will drive the same bullet to 3600 fps.

The odd case head size on the Weatherby will actually fit the bolt face of a AR15/M16 but if it's an issue it could simply use the standard .223 head size with a rebate.

If shortening the case to achieve the correct AOL to work in a magazine reduces the case capacity to where to desired 3000 fps with a 100/105 grain bullet is lost one could simply form the case with nearly straight walls and take a bit of the taper out and replace the lost case capacity grain for grain.

The increase in case diameter of .039 inches would reduce the magazine capacity as it exists by one round. One could probably design a spring or follower that would negate that as an issue.

Like I said there isn't much new.

It's sort of like the short mags for all the hoopla, most were designed about 40 years ago in one form or another.

It is fun though to play with this stuff and design cartridges.

The best and have fun, that's what it's all about.

Ross

Ergonomic def 2 -http://www.merriam-webster.com/dictionary/ergonomic

Neck length is 6.2mm = .244 in.

.224 Weatherby case diameter is way to large, its very close to the 6.8spc. The 6.8spc has lost 5 - 6 rounds in the standard M16/AR15 magazine. There would be no gain in mag capacity over the 6.8spc.
 

picketpin

Buckeye
Joined
Jun 29, 2006
Messages
1,544
Not to argue I really don't care and doudt very seriously that this is something that will fly but that is something you can deal with if you want.

As far a diameter. The larger diameter of the Weatherby case is the belt. I already specifide lose the belt. After that the width of the case at the widest point is .415. Widest point of the .223 case is .376 a difference of .039. Divide that into the diameter of the existing 223 case and it seem you would lose 1 case out of ten due the increased diamter or in a 30 round mag, 3 rounds. Some of that surely could be accomadated by a redesign of the mag itself.

I can make it as a modern case of standrd configuration, little or no slope, sharp shouder and adaquit neck and easily get enough powder capacity to launch 100/105 at 3000 fps from the AR platform.

Oxford English Dictionary does not show a second definition for the word and I have to admit I've never heard it used in relationship to cartridge design in the last 40+ years. But I could certainly be wrong

Good luck

RWT

So did you want comment or simply a blanket endorsement of your concept/idea??
 

deadduck357

Single-Sixer
Joined
Jul 2, 2007
Messages
404
I would like to see your cartridge, we need to do whatever we can to try to get our boys over there in the sand something better than the 5.56.
 

picketpin

Buckeye
Joined
Jun 29, 2006
Messages
1,544
Duck: I was reading your information and simply went out and looked through my reference stuff when I ran across the 6mm/.224 Weatherby.
I actually knew it was in the Ackley books. I shoot a weatherby .224 in an original Weatherby "Varmintmaster" and have killed some deer and antelope with it using 60 grain Noslers.

The rest was just a quick look at the two cases and miking them and measuring case capacities.

I have a question about using a 6mm bullet. It should be possible to use the modified .224 case to fire a 90 grain VLD .224 bullet at least 2800 fps. I shoot 90 grain Bergers and some custom 105 grain bullets in custon #1s in 22-250 Ai with a 1;7 twist and another 22-6mm Remington with a 1:6.5 twist at varmints at ranges out to 500 -700 meters. They kill coyotes pretty well and have a B.C of over .500 which is at least double the ballistic coefficient of the besy 55=60 grain .224 bullet. They in fact have a higher B.C. than the 6mm 100-105 bullets. Just a thought.

It would be easy to chuck a .224 Wby case in the lathe and turn the belt of and rebate the rim and get the right length. It would be a little harder to get the shoulder modified with a chambered rifle or a hydrolic press.

I am going to try and move the should back a bit. I have enough different dies that I think the 22PPC or 22 BR dies are fat enough I can run the Weatherby brass up into them and moving the shoulder back.

I'll spend a little time this weekend and do an engineeering drawing of the case/my idea and e-mail it off to you.

the best

Ross
 

deadduck357

Single-Sixer
Joined
Jul 2, 2007
Messages
404
You could e-mail to me but more importantly it would be better served sending it to someone that could manufacture brass so it could be tested. The faster the better, the sooner a round could get out there so the military could look at it, the better for our boys.
 

picketpin

Buckeye
Joined
Jun 29, 2006
Messages
1,544
Well the goverment/mlitary has the money and the resources to do it in a week or less if they were inclined to due so. If they aren't addressing it with goverment resources the question would be, does the goverment/military really consider it all that important.

I'm pretty knowledgable after 50 years of this shooting/reloading game but suspect the goverment has one heck of a lot of resources and expertise than ole Ross.

The best
 

Sig685

Single-Sixer
Joined
Oct 21, 2003
Messages
177
Is this a private conversation or can anyone come out and play?

Duck, I like your thinking and I know your heart is in a good place, and I truy hate to rain on your parade, but you're on the planet here. There is absolutely NO way .mil is going to change caliber for their primary issue weapon in the middle of shooting wars; that is pure insanity and a surefire recipe for disaster.
There is nothing wrong with the 5.56 cartridge, there is plenty wrong with the bullet. The 62 gr M855 loading is just a little less than useless; it is spun too fast and does not create enough trauma on the target. This round was designed to defeat light body armor in Soviet block countries.

In actuality the M193 has more wounding capacity than the M855 by virtue of the fact it yaws on impact and fragments. However, this effect if dimished to some degree bythe 1:7 twist of the current issue M16.

However, the .mil has been acquiring and issuing the Mk262 mod 1 which consists of a 77gr OTM bullet, and reports indicate this loading is a lot more effective on target. It has greater ranger, higher BC and SD and hits harder that tne 62gr M855. What is does not have is barrier penetration and for that you simply need more mass.

Your 6.2 OCC is simply not incrementaly better than the MK 262 mod 1 loading and would require vast amount of changes (and chaos) with respect to logistics, equipment, training and use. All that effort for virtually no improvement over the Mk262 mod1. I would also suggest that switching calibers during shooting wars will cause some of our people to be killed and that's really not what you want.

Beyond that, your predicted velocities are less just say, optimistic at best, especially in shorter barreled rifles. The little extra weight you mention is nice, but not at the expense of so much velocity.

If I were in the .mil and in charge of looking for the next weapon/round, I would definitely grow the magwell of the next issue weapon some; the one of the AR-15 is too constrictive. But I would not go as bing as the one for the AR019, that's too big. Just like in the story of the three bears, we need something "just right".

Also, just so you know, this season I hunted with one of my AR-15s loaded with 75 gr hunting bullets; the bullet performed extremely well. It's too bad our guys are constrained by the stipulations of The Hagues treaties, which of course have no application when dealing with terrorists.
 

deadduck357

Single-Sixer
Joined
Jul 2, 2007
Messages
404
SIG685, please, I am looking for replies. I understand everything you have stated, I have done much research. If I didnt think there were no advantage to this cartridge it wouldnt hurt my feelings. But I do feel it has some advantage over the 5.56 . The 6.2mm CR ballistics will be superior to the 5.56Nato and the 6.2mm MR ballistics will be superior to the MK 262 Mod 0 or Mod 1.

I have run some figures on my 6.2mm OCC albeit they are my figures. I have sent a prototype to Superior Shooting Systems Inc., Tyler and David Tubb are going to run figures, was told they were going to take to the Shot Show. I'm not sure what their figures are but they said they will let me know after the Shot Show. Will see what they came up with then.

I see the point if we were to go to a new platform then any new cartridge would be possible. But if were stuck with whats at hand then we need to try something. Both the 6.8spc and 6.5 Grendel have tried.

The problem with the 75 - 77gr projectile out of the 5.56 case is it's impeding into case capacity, the 6.2mm up to 90gr does not impede into the cases powder capacity.
 

Sig685

Single-Sixer
Joined
Oct 21, 2003
Messages
177
Duck, I'm not sure you understand what I said. While I agree that you cartridge may have better performance that a regular 5.56mm cartridge, the huge expense that would be incurred in barrel swaps, possible magazine swaps, probable bolt swaps and the logistics train to suppoer tall this, only to gain a small increment in performance is sinply not worth it. Add to that the fact your cartridge wouldbeat up the rifle more, and then you have other issues.

On top of that, the .mil acquires and stockpiles M855 and Mk 262 in large industrial quantities; to ramp up production of your round at the same level would require some time and of course would require contracts and royalties and so on.

I simply do not think that your cartridge represents much of an increase over the Mk 262 to warrant such a huge fuss. Good luck with presenting it at SHOT show.
 

deadduck357

Single-Sixer
Joined
Jul 2, 2007
Messages
404
Sig685":ognwvvce said:
Duck, I'm not sure you understand what I said. While I agree that you cartridge may have better performance that a regular 5.56mm cartridge, the huge expense that would be incurred in barrel swaps, possible magazine swaps, probable bolt swaps and the logistics train to suppoer tall this, only to gain a small increment in performance is sinply not worth it. Add to that the fact your cartridge wouldbeat up the rifle more, and then you have other issues.

On top of that, the .mil acquires and stockpiles M855 and Mk 262 in large industrial quantities; to ramp up production of your round at the same level would require some time and of course would require contracts and royalties and so on.

I simply do not think that your cartridge represents much of an increase over the Mk 262 to warrant such a huge fuss. Good luck with presenting it at SHOT show.

SSS inc. will be taking it to Shot Show.

I realize what you have said and know the odds against it. But some SOCOM have fielded the 6.8spc in Iraq & Afghanistan. So there could be some possibility for this 6.2 round.

You may be right about the amount of increase between the 5.56 & 6.2, I will not know until some figures and tests are run. But if there were a couple hundred FPE of difference wouldn't that make a difference ?
 

Sig685

Single-Sixer
Joined
Oct 21, 2003
Messages
177
Lots of people take a lot of things to SHOT show, so let's wait and see.

I just spent some time at JBM doing some numbers. I am NOT comparing your 6.2 OCC to the 5.56 NATO, I am comparing it to the Mk 262 load. I would think that you would agree with me that is is FAR easier and FAR cheaper to mass issue the Mk262 (and with no deadly logistical consequences to boot,) than to introduce a new caliber for the existing equipment. If you do not agree with that, then stop reading right here.

I used a figure of 2500FPS for the Mk262, even though I know it's higher in 16 and 20 inch barrel, but the M4A1 now rules. At the muzzle, the energy is 1068ft/lbs, at 100yards, it's 920 and at 200 it's 788.

Using a 75gr 243 bullet as you mentioned in your paper yields energy figures that are smaller than the MK262 for the same velocity; in fact, I had to add 200FPS to exceed the Mk262's energy level. Increasing the bullet weight is probably not an option as the bullet will get longer and dig into the case more; that 2.26 mag limit is a Rosie O'Donnell. (Note: I used a more colorful word here, rhymes with 'witch', but the software changed it automagically (and for the better, I think.)

So as you can see, you have an uphill fight.

Some people might say, well SOCOM uses the 6.8, maybe they can use the 6.2 also, or instead. The answer to that is a simple "why would they want to do that?"

The (very) slight and dubious improvement of the 6.2 over existing loadings is simply not worth the huge associated costs and possible loss of life.
 
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