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 6.8mm vs. 7mm vs. 6.5mm vs. 6mm - ballistics questions
DrEvil  [Member]
12/13/2003 12:05:14 PM EDT
Just a more general question than "hey did you guys know there was a new 6.8mm SPC round."

1) I don't know much about the 6mm SAW round but didn't it already have a lot of R&D behind it in the 70's/80's - so why go through the trouble to developing the 6.8mm SPC? Sounded like a great performer.

2) 6.8mn & .276 pederson & .276 british and .280 british are all ~7mm. And prior to WW2 the germans played around with a 7mm intermediate cartridge. What's so magical about the 7mm limit?

3) And why not ~.25 calibre? I vaguely remember reading some history where the US army(?) tested various rounds (I think .22, .256, .276) against anesthetized animals and the .256 performed the best, but decided to go with the .276 Pedersen mostly because of the positive psychologic effects on our troops of firing a "bigger" bullet.

No flames - just looking for enlightenment.
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TonyWilliams  [Member]
12/13/2003 11:08:26 PM EDT
You might find this of interest:

With 115 grains at 2,650 fps, the 6.8mm is very close in performance to one of the 'ideal' rounds suggested in the article.

Tony Williams: Military gun and ammunition website and Discussion forum
sloth  [Member]
12/14/2003 5:09:29 AM EDT
I personally think that abandoning the 6mmSAW was s ignificant mistake on the part of the military. I'm not familiar with the type of bullet used, but it would be lethal if it was prone to 5.45 type tumbling.
slidestop  [Team Member]
12/14/2003 10:17:02 AM EDT
When the military changes over too the 6.8x43 (6.8 Remington SPC ) What will this do the 5.56 ammo supply . Will it be as cheap as it is now or get more expenisive ? Something to think about for down the road.
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DrEvil  [Member]
12/14/2003 5:00:06 PM EDT - yeah, that was one of the things I read online that made me question why go to a ~7mm bullet. Seems like a 6.5mm round would have a flatter trajectory beyond 400-500m.

Or do we need to be at least 1mm bigger than the chinese?
imposter  [Team Member]
12/15/2003 11:03:05 AM EDT
If you think about it, all of the popular American big game cartridges are either 30 caliber or 270/7mm. Nothing smaller has ever caught on. The top five most popular deer cartridges are 30-06, 270 Win, 7mm Mag, 308 an 30/30. Those five account for like 80% of the total. 30-06 and 270 account for more than 50%.

Although I know many here hold hunters in disdain, hunters always want "enough gun" and they seem to be telling us that .264/.257/.243 calibers do not cut it.
TonyWilliams  [Member]
12/16/2003 5:19:43 AM EDT
To some extent the popular calibres may be down to 'who got there first', marketing etc.

I have heard that the Swedish 6.5x55 is highly regarded by its users as a hunting round, both in Europe and the USA.

Tony Williams: Military gun and ammunition website and discussion
juslearnin  [Member]
12/19/2003 2:13:16 PM EDT
Go to, look under the "terminal effects forum" at the thread "6.8x43 SPC rifles". The moderator there is a Dr. Gary Roberts, who supposedly has been testing and evaluating this round for the military, and there is a lot of information. He says that the 6.8 was arrived at after a lot of real world testing based on their criteria of ballistic performance and wounding ability and that it seemed to balance these two the best of all the options evaluated.
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