5.8mm vs. 6.8mm

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5.8mm vs. 6.8mm

Postby JOHN THURSTON » Fri Mar 07, 2008 3:47 am

While the Chinese army, as reported, has adopted the 5.8mm calliber for its new line of assualt rifles, as reported, the US appears to be leaning towards the 6.8mm cartridge for its new M-8 Assault rifle.

The British conversely but historically intended to adopt a 4.25 mm round and/or a 4.85mm for its own army.

This was done away with when the 5.56 mm Nato round was officialy adopted by the alliance.

The M-8 AR is reported to be more reliable and require much less maintainance than the M-4 Carbine or the Standard M-16 A1 and A2.

In the interim period, also as noted, new upper assemblies could and may be produced in the 6.8mm cal. as the new Assualt Rifle is phased in and/or goes through the teething in period typical of most new weapons systems.

Although this .270 cal round is quite diferent from that considered by the Army in the late 30's (the .276), if I recall correctly, for which which the Pedersen weapons system was originally designed.

Ironically, the Army did not consider the round powerful enough.

Also as noted the base (physical case head)for the new cartridge appears to be the 1906 vintage 30 Reminington cartridge and the development cartridge appears to be the "6.8mm Secial purpose cartridge.

The .30 Remington rifle wasa semi auto of odd design and mediocre hunting power-whose report even sounded odd in the field.

l originally thought that the US and the PLA would be adopting, at least diameter wise, the same caliber weapon.

The 6.8mm SPC could launch a 90 grain pill at about the smae velocity as the present 5.56mm launces its 55gr m185 and ss109 projectiles.

I Am still re researching this mattes, it is a bit tangled..

Don't mistake me, in most arenas the 5.56mm have proved its mettle, but the thought of a more effective cartridge which would fit both the new M-8 design and stilll be usable (albeit with new upper asemblies) in present US small arms seems the best of both worlds---except in the area of logistics should both calibers be fielded at one time.

Well, of course, at one time,during WWII)--the Army had to supply the .45 acp, .30 M2, and.30 Carbine qmmo at the same time to the troops in the fieild, so it is a problem that has been met and dealt with before.
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Ugly duckling

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Postby JOHN THURSTON » Sun Mar 16, 2008 6:39 pm

The XM8, for whom the 6.8mm SPC may have been intended has been cancelled, apparently.

The Caliber is not dead.

Ar-15 "Uppers" and, I think, complete Rifle are available commercially and the rumor mill is that the army has Ordered 15,000 "uppers" in this caliber for the M-16.

This is hedgeing one's bets for sure.

If a new assualt rifle is adopted, at some point, It will, in all likelihood, been compatible with the 6.8 SPC and the 5.56mm Nato.

Many US "ugly ducklings', have been turned around in the past.

The Marines were not hot about the M-1.

the F-16 hqad a bad crash record and suffered from "fraying" of it's wiring harnessees in the "fly by wire system.

The Bardley IFV still mystifies me, too big to be called a scout vehilce, too much space occupied by the 25mm chain gun for carrying more than 6-8 troops.

It original specs also called for it to be amphibious.

I am not sure about that one. It is too large to be readily airtransportable and the 25mm main gun probably too small to engage 'thick skinned' vehicles.

this is one case where just copying the Soviet BMP would have been a good idea (opposing opinions welcome)

The Stryker armored vehicle is, on the other hand, something of a success story and has shown its ability to takepunishment and navigate the narrow streets of Iraqi citie and stll carrry more troopers than the Bardley.

of course the M-16 itseld showed many teeething problems--related imho to the change in powders from the test cartridge, the quirky Llungman Gas system, the lack or a forward assist, the misinformation (or non info) giwen to the troops when first issued---etc.

The F-111 had several unexplained crashes in Vietnam when operationg from Thailand.
(One I think crashed in the White Moountains when I was young(er) and that site was sealed off very quickly.

At the time the ANG was still operating the venerable F-84 Trunderstreak--and we used to seee then fliying been mountains back in the day, so it could have have been and F-84 that went down--no real way for me to tell, but the "East Branch" road near No. Conway was closed for twon weeks.

The Abrams evolved out of the snake bitten MBT70 Program.

I guess one never knows how things will turn out.

I do apologize for thinking the M-8 was still in development---my bad.

It should be noted that the British Enfield Bullpup design had problems that had to be straighten out, allegedly, by H&K.

It is very heavy for it's size.

The (imho) ideal gas operating system is perhaps that type used by the SKS and The FN slr/FAL--in these systems a piston is pushead against the bolt face.

As noted the piston and bolt assembly in the AK are basically one big moving part---and the short sight radius is not lieable to most Americans.

The M-14 system was somewhat similar and did not, like the M-16, allow burning propellant gases to derectly enter the bolt system.

The only flaw in the beloved m-1 was the somewhat overlarge Operating rod and the fact that dirt could enter the rifle down thru the turnbolt system.

The first flaw was coreccted in the M-14, but not the second.

Still, both systems worked once understood.
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