From Evan Marshall - a new military round is ready to replace the 5.56x45, or .223, the 6.8x45. It is said of a 120 gr. 6.8mm bullet at 2700+ fps. Fuzzy stories of long shots from m16s beeing stopped/slowed down by those voluminous clothes people use around Iraq may have some substance, after all. Only barrel replacing in current m16 would be necessary, because the new round fits original magazines. I keep wondering, if those ballistic numbers are real, about the pressures involved, unless a really new breed of propellant has been develloped. But enough of this. would it not be a wunderbar cartrige for a little streamlined svelte really lightweight short actioned bolt action sporter?
What I have heard is the 6.8X45 cartridge is under development as a special operations caliber option in AR-15/M-16 type rifles.
The 6X45 is a very successful wildcat in South Africa that has recently been granted factory status by one of their ammunition makers. The usual rifle for such is built on a small bolt action, and they are really trim and light.
Wildcatters have been fooling with the .223 Remington case for years, for example the TCU series of cartridges. (I have a 6.5 TCU Contender).
jim dodd
Posts: 4166 | Location: San Diego, CA USA | Registered: 14 November 2001
I played with a contender in 6.5 TCU for a while. It was a very fun little round. Very accurate and decent velocity. With 120 grain bullets it should have very good penetration also. I think it would be a great improvement overthe .223.
The problem with the 5.56 failing to stop enemy combatants in Afghanistan is caused primarily by the use of the SS109 round. It penerates well, too well. Military cartridges don't expand, they achieve their greatest wounding potential by swapping ends after impact. During its yaw, the stress exerted on thre bullet may cause it to break up, this fragmentation will destroy tissue in the temporary stretch cavity thus increasing wound effect. This property is limited by the SS109 cartridge, it'll penetrate a steel helmet at 600m, but has achieved a pretty poor record in our latest military confrontations.
I played with the numbers trying to convert inch calibers to there metric equivlent and have found that they certainly round alot of calibers off.
.243" = 6.1722 mm .264" = 6.7056 mm .277" = 7.0358 mm .284" = 7.2136 mm .308" = 7.8232 mm Yep thats a 7.8232mm .323" = 8.2042 mm .366" = 9.2964 mm
As you can see alot of military calibers have been rounded off. like the 308 which I believe is called 7.62mm by the military. As far as I know Lazeronni is the only one calling there 308's 7.82mm's. So I would not be surprised at all if they were going to be using .264" bullet for this new round. Could be a good thing for all of the 6.5mm shooters out there.
Posts: 968 | Location: British Columbia | Registered: 29 May 2002
Unfortunately, this is the second go around for such an idea. The had the .276 Pederson, or the Brit equivalent been adopted, we probably wouldn't have these problems now. There have been several studies of the ideal infantry cartridge and they all end up declaring a bore diameter in this neighborhood, a MV of 2700 FPS and a bullet about 130 grains in weight to be ideal.
I have a .276 Pederson in my possesion, it's a really neat round. It's slightly longer than a 5.56NATO, short neck, considerable taper in the case body and a very generous rim. It looks like it's designed for reliable feeding and extraction in automatic weapons.
Imagine a FN FAL chambered in this caliber with an 18" barrel, mounting modern military optics i.e. Aimpoint or ACOG, modern accesories like a Vortex flash hider and a Surefire white light... Kind of makes the M-16a2 / M4 look pretty anemic huh?
If they do develop it, I doubt it will be standard isue to all troops. It comes down to weight.
If you increase the weight of the bullet by more than 200% (55 gr to 120 gr) you will reduce the number of rounds ground troops can carry. The case and dimensions may remain the same, but not the weight. The weight of ammo was one of the reasons the US military did away with 30 caliber rounds for the troops.
Probably work for special circumstances though.
Mac
Posts: 1638 | Location: Colorado by birth, Navy by choice | Registered: 04 February 2001
quote:Originally posted by markus: I played with the numbers trying to convert inch calibers to there metric equivlent and have found that they certainly round alot of calibers off.
.243" = 6.1722 mm .264" = 6.7056 mm .277" = 7.0358 mm .284" = 7.2136 mm .308" = 7.8232 mm Yep thats a 7.8232mm .323" = 8.2042 mm .366" = 9.2964 mm
As you can see alot of military calibers have been rounded off. like the 308 which I believe is called 7.62mm by the military. As far as I know Lazeronni is the only one calling there 308's 7.82mm's. So I would not be surprised at all if they were going to be using .264" bullet for this new round. Could be a good thing for all of the 6.5mm shooters out there.
Markus,
This little discovery is the root of a lot of confusion, even with inch designations. You are figureing the bullet size, which is also the groove size. The metric designations are the bore size. This is the same reason that a .300 mag. uses the same bullet diameter as the .308 Win.
Of course, there are a lot of cartridges where this doesn'y even explain the oddities. Some cartridges are just named for whatever the designer dreamt up. (E.G. .38-40 Win., with a .401 bullet dia.)
Mac: Czech "standard" troops carry 150 rounds (4 reserve 30 round magazines + 1 magazine in rifle) of 7.62x39 ammunition without problem. Also battle calculations say that there is no reason for more ammunition because limited troop life. I belive if there is no problem with 150 rounds of 7.62x39, there will be no problem the same ammount of 6.8x45. Or do you think troop will needs more ?
quote:Originally posted by J.W. Blute: The 6.5 TCU (A 223 necked up AND IMPROVED) only produces 2200fps with a 120gr bullet. I don't see them getting 2700+fps out of a case this size.
2700+fps is more in line with what a standard loading of the 6.5X55 produces.
In a pistol, 14". In a rifle length barrel you should get about 2500 fps.
Posts: 2324 | Location: Staunton, VA | Registered: 05 September 2002
There was once a 6.9X57mm Chinese military round, probably for a Mauser action rifle. Some believe that the .270 Winchester was an outgrowth of this experimental Chinese cartridge. I am assuming here that this 6.8X45 is a necked-up 5.56mm case shooting a .277" bullet? Is that what we're talking about? If so, it would be somewhat comparable to the experimental .280 caliber the Brits were pushing at the time we forced the 7.62X51 on NATO, not too long before we switched to the 5.56mm!!
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(E.G. .38-40 Win., with a .401 bullet dia.)
