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Posted: 9/10/2005 9:38:58 AM EDT
Just think...if sometime in the 1950's when the new US (and by default Free Word) miltary cartridge, if some brave engineer would have squeezed the .308 case down to 6mm, what would the result have been?

Would the M-14 have been more successful than it was?

Would the M-16 have been short-circuited?

Could the .243, given the proper weight FMJ bullet preform in the Machine Gun role also?

Would it have been controllable in full-auto fire out of a nine-pound rifle?
Link Posted: 9/10/2005 9:47:25 AM EDT
Link Posted: 9/10/2005 10:38:02 AM EDT

Originally Posted By Aimless:
I think the initial proposal for the Garand was supposed to be a .243 (or something like that) but the Army said they had too much 30-06 to switch.



It was a .276 cartridge.
Link Posted: 9/10/2005 11:16:48 AM EDT
Link Posted: 9/10/2005 12:06:41 PM EDT
.243 wouldve been much better than .223 is, too bad they didnt see it back then.
Link Posted: 9/10/2005 12:09:54 PM EDT
Link Posted: 9/10/2005 1:39:12 PM EDT
6.8 SPC Has about the same bullet diameter are a .243
Link Posted: 9/10/2005 1:57:43 PM EDT
But the .243 has lots more oomph...

Maybe TOO MUCH?
Link Posted: 9/10/2005 2:01:13 PM EDT

Originally Posted By AyeGuy:
But the .243 has lots more oomph...

Maybe TOO MUCH?



Maybe, but it would still be pretty viable downloaded.

I think it would have been successful.
Link Posted: 9/10/2005 2:12:57 PM EDT
.243 doe snot have too much oomph........


It was th efirst firearm I EVER shot, bolt action and I was 8 at the time. It is anice light cartridge that gets the job done, far and away better than .223....


that all said, I love 30 cal rounds, and think the Garand and M14 are great rifles
Link Posted: 9/10/2005 2:13:48 PM EDT
Although it would have worked well at long range, assuming you used a proper bullet, .243 is still MUCH too large to be used in a lightweight automatic weapon, and the weight and size of the cartridge basically make it much inferior to the 5.56mm.
Link Posted: 9/10/2005 2:15:23 PM EDT
Where does it fall closer to balistically at longer ranges and penetration: .223 or .308?
Link Posted: 9/10/2005 2:34:49 PM EDT

Originally Posted By Combat_Jack:
Although it would have worked well at long range, assuming you used a proper bullet, .243 is still MUCH too large to be used in a lightweight automatic weapon, and the weight and size of the cartridge basically make it much inferior to the 5.56mm.



+1

Any weapon chambered in .243 would require .308-sized magazines, and would probably be limited to 20rds capacity. I'm pretty sure the .243 cartridge is dimensionally identical to a .308, except for the neck.
Link Posted: 9/10/2005 2:48:27 PM EDT
60 rounds of 5.56 in mags weighs the same as 20 rounds of 7.62.
Link Posted: 9/11/2005 9:53:59 AM EDT
The 6X45mm is a cartridge based on the 5.56X45 by necking up to 6mm. While this is not as big of a jump as the .243 it does allow the same weapons platform to fire a 10 grain heavier bullet at the same velocity. The big advantage is that all parts of the AR15/M16 stay the same except for the 6mm barrel.

Many do not see this as much of an improvement, hence the appearance of the 6.8 SPC and 6.5 Grendal.

Joe
Link Posted: 9/11/2005 1:05:39 PM EDT
In the military required FMJ form, the .243 would not be as effective as the 5.56mm.
Link Posted: 9/11/2005 6:05:26 PM EDT
[Last Edit: 9/11/2005 6:07:03 PM EDT by bishopm14]

Originally Posted By triburst1:
In the military required FMJ form, the .243 would not be as effective as the 5.56mm.



The constuction characteristics that make 5.56 deadly could be applied to any other caliber as well. A 90 to 110 grain 6mm FMJ with the same fragmentation tendencies as M855 would truly be a miniature version of "Shock and Awe" to see in action.
Link Posted: 9/11/2005 7:28:32 PM EDT

Originally Posted By AyeGuy:
Just think...if sometime in the 1950's when the new US (and by default Free Word) miltary cartridge, if some brave engineer would have squeezed the .308 case down to 6mm, what would the result have been?

Would the M-14 have been more successful than it was?

Would the M-16 have been short-circuited?

Could the .243, given the proper weight FMJ bullet preform in the Machine Gun role also?

Would it have been controllable in full-auto fire out of a nine-pound rifle?



I have always wondered this as well...
Link Posted: 9/11/2005 7:39:24 PM EDT

Originally Posted By JaredB:
6.8 SPC Has about the same bullet diameter are a .243



No, the 6.8 SPC shoots a .277" projectile.
Link Posted: 9/12/2005 6:28:08 PM EDT
There is one way I know of that you could do some
tests and answers some of your own questions.

JLD Enterprises currently produces a barrel calibered
in .243 that will fit into a HK-91 receiver.

They haven't sold many ,mostly because people want
it in the standard .308 to use surplus ammo for
cheap shooting.

If I had the $$$$ I would be interested in paying a builder
to press in a .243 barrel for me.

It might be interesting to be able to really compare it.

They've sold a few of these ,so somebody's tried it ,or is
considering it enough to shell out the cash for one.
Link Posted: 9/12/2005 11:35:05 PM EDT
I think that the brief answers are:

Yes, it would have been an effective military round given a well-designed bullet. There might have been a case for two different loadings: a heavy, long-range bullet for MG and sniper rifle use, and a lighter one with less recoil for the rifles. The lighter recoil would have made the rifle much more controllable in full-auto fire than the 7.62mm guns.

The main technical problem would have been that the size and weight of the ammo and the guns would have been much the same as the 7.62mm weapons, as already mentioned.

Even worse would have been the political difficulties in getting this adopted. The British, Belgians and Canadians all argued strongly for the adoption of a lower-powered .280 cartridge but the US Army Chief of Staff refused to contemplate anything other than a full-power .30 calibre round to replace the .30-06 - resulting in the 7.62mm NATO.

Tony Williams: Military gun and ammunition website and discussion forum


Link Posted: 9/13/2005 12:59:46 AM EDT
I don't think the .243 has anything to offer over the 7.62 NATO. They both are too much for any type of light automatic weapon which is required to fire fully automatic with any great effect.
Magazine capacity in the magazine is abysmal for both rounds, compared to literally twice as much in some 5.56 weapons. Much has been made of reverting to the 6mm bullet for a military cartridge. 6mm cartridges were used by several militaries and were eventually discarded for larger bullets. In most cases, lethality was inferior. The concept of a 6mm combat weapon is by no means new. Engineers and Commanders are always fighting the last war...After WWII it was detachible magazines for rifles chambered for heavy rifle rounds.

After the Korean war we realized that nearly all combat was at ranges under 300 yards and many soldiers were reluctant to engage targets at 100 yards. Vietnam reaffirmed this principle and proved that our current 7.62 battle rifles were woefully inadequate to fight a modern war. Current warfare is fast and fluid. The days of storming a beach and punching a Nazi are over...Now its about generating an overwhelming amount of fire to eiether break contact, manuver against an objective or defend your position until a B-1B or an AC-130 can help a few cave dwellers

find Jesus. An extremely small percentage or all combat killed is from small arms fire. Even a M2 in .50 BMG cant compare to a 2000 lb JDAM or precisely massed, GPS directed artillery. Our current 5.56 weapons provide soldiers to carry a maximum amount of ammuntion which can be fired rapidly and accurately with increased effect. Lethality with the 5.56, especially the MK262, under ideal conditions is actually superior to that offered by the M80 7.62. *I am not saying every 5.56 is better than every 7.62, just that the M193, M855 and Mk262 are superior to standard M80 ball* The 5.56 offers an acceptible level of lethality when used within its envelope.
If the 5.56 was so ineffective or there was a better alternative for modern warefare it wouldn't be in service with just about every major military power...save China and Russia, whose rounds are arguably better due to more extensive development however, the concept is the same.

Afghanistan is the exception to the rule requiring a "band aid" solution, such as the Mk12, MK262 and reissuing M14's, not re-equipping our entire military with a larger bullet base on "percieved" deficiencies and isolated condtions which occured in a unique theatre. The 6.8SPC will continue to find favor in the spec ops community, but will never be adopted as a standard service round.
Been there done that. I belive the next round we adopt will be under 6mm and will utilize a more advanced bullet, perhpaps blended metal technology.
Link Posted: 9/13/2005 3:28:50 AM EDT

Originally Posted By Ryno_the_wyno:
I don't think the .243 has anything to offer over the 7.62 NATO. They both are too much for any type of light automatic weapon which is required to fire fully automatic with any great effect.


Assuming a 100 grain bullet at 3,000 fps, the recoil factor generated by the .243 cartridge would score around 80, compared with 142 for the 7.62mm M80 ball, 59 for the 7.62x39, 71 for the 6.8mm Rem, and 90 for the British .280 EM-2. This is assuming that the rifles they are fired in are all equal. So while it would kick a bit harder than an AK round, it would be a lot more controllable than any 7.62x51 rifle.


Much has been made of reverting to the 6mm bullet for a military cartridge. 6mm cartridges were used by several militaries and were eventually discarded for larger bullets. In most cases, lethality was inferior.

Nearly all of the early small-calibre rounds used round-nose bullets which zipped straight through without tumbling. Anyway, the priority then was for long-range MG fire, not short-range fire from automatic shoulder guns.


Lethality with the 5.56, especially the MK262, under ideal conditions is actually superior to that offered by the M80 7.62. *I am not saying every 5.56 is better than every 7.62, just that the M193, M855 and Mk262 are superior to standard M80 ball* The 5.56 offers an acceptible level of lethality when used within its envelope.

I think that there might be some dispute about the relative effectiveness as conditions tend not to be "ideal". But in any case, the question was about whether the .243 could have been an effective military rifle round, not whether it would have been the best possible. As it happens, I think that a more compact, lower-powered 6.5mm would have been better, with ballistics similar to the 6.5mm Grendel (although ideally with a longer and slimmer case).


Afghanistan is the exception to the rule requiring a "band aid" solution, such as the Mk12, MK262 and reissuing M14's, not re-equipping our entire military with a larger bullet base on "percieved" deficiencies and isolated condtions which occured in a unique theatre.

You can't get two theatres much more different than Afghanistan and Iraq, but I've read a number of criticisms of 5.56mm performance in both places.


I belive the next round we adopt will be under 6mm and will utilize a more advanced bullet, perhpaps blended metal technology.

I thought that the claims for that design had been - shall we say - robustly criticised on this forum, among other places?

Assuming that the stalled selection process for the next generation of US small arms gets under way again, whatever calibre they are bought in is likely to remain the standard until Star Trek's Phasers are perfected.

Tony Williams: Military gun and ammunition website and discussion forum
Link Posted: 9/13/2005 3:44:39 AM EDT
On a historical note the USMC issued a 6mm Lee Navy rifle back in 1895. It was a straight pull rifle that at the time eroded barrels. The Marines used it in China during the Boxer Rebellion.

CD
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