[constructor]

Read this article, Kind of made me think about a 6.8x45 since I already have the barrel specs down.
I think this would hit the velocity of the Rem 6.8x43 SPC and use a 5.56 bolt, 5.56 mags hmm magpul
Ideas come from the strangest places.

http://www.militaryphotos.net/forums/archive/index.php/t-101511.html

 

[ron169]

You and your damn wildcatting! H, if the 6.8X45 can hit the same max velocities as the 6.8X43, why didnt they try that first? Seems like that would have made since.

 

[constructor]

You and your damn wildcatting! H, if the 6.8X45 can hit the same max velocities as the 6.8X43, why didnt they try that first? Seems like that would have made since.

Not the 6.8 as it is now but the 6.8 as it was with remington at the helm.
100gr bullet at 2670fps from a 16" barrel.

 

[ron169]

So after a few months of Hot Rodding, now you want to build a Sedan that fits in the mags and gets good gas mileage

 

[constructor]

So after a few months of Hot Rodding, now you want to build a Sedan that fits in the mags and gets good gas mileage

Months? I have been at the 6.8 for 4 years
Just covering all the bases, 6.8 necked down to .224 and .243 and the 6.8 itself
the .223 necked up to .243 and .277
it is funny how I skip that 6.5 every time

 

[ron169]

Lol, not just a little biased are you! Although the 6.8X45 does sound interesting, just seems a little pointless since the 6.8SPC already has a large supply of bolts, mags being made for them. What would be perfect is a new weapon platform with allowed a loadable mag length of 2.4-2.5 inches or so. Not quite an AR-15, and not quite an AR10 either. What is that complany that makes modular lowers with different mag lengths?

 

[joshuades]

How does the 6x45mm run? It would seem like a more reasonable alternative given the the case size of the 5.56.

 

[constructor]

Lol, not just a little biased are you! Although the 6.8X45 does sound interesting, just seems a little pointless since the 6.8SPC already has a large supply of bolts, mags being made for them. What would be perfect is a new weapon platform with allowed a loadable mag length of 2.4-2.5 inches or so. Not quite an AR-15, and not quite an AR10 either. What is that complany that makes modular lowers with different mag lengths?

MGI.
The mil trials are in July and Aug. I know someone who is submitting a 6X45.
The thing that makes that attractive is only the barrel and bullets are different, all of the old mags work, the web gear works, the links work, same bolts in supply.
Any new rifle, bigger mag will mean all new parts and web gear to fit the mags or links and belts to fit the
new case size etc, etc. and that is a lot of trouble to outfit the whole army.
With a 45mm case the bullets must be short to fit in the mag so that means light 6mms (see below) or .277s, IMO the 6.5 bullets are just too long.
I agree the 6.8 has much more performance but changing mags and bolts may be enough that they kick it out. The fact that SOF is using it and the big green is getting feedback from that is a good sign.
J,
the 6x45 is so long and mags so short that light 85gr and under bullets must be used and that isn't any better than the 77gr 5.56. so that's why I thought of the .277 bullets they are larger dia so they can be heavier and shorter but not too heavy like 30s would be.

 

[stanc]

Read this article, Kind of made me think about a 6.8x45 since I already have the barrel specs down.

You mean, something like this?
http://www.defensereview.com/68x45mm-kramer-urban-combat-cartridge-ucc-for-urban-warfare-ops/

 

[constructor]

You mean, something like this?
http://www.defensereview.com/68x45mm-kramer-urban-combat-cartridge-ucc-for-urban-warfare-ops/

Yes, I remember reading that last year sometime.

 

[stanc]

Yes, I remember reading that last year sometime.

So would yours be different?

 

[joshuades]

It just occurred to me that because of the smaller difference in the circumference of the round to the case, might it be possible to load a faster powder with this round and still be within safe pressures?

 

[stanc]

Although the 6.8X45 does sound interesting, just seems a little pointless since the 6.8SPC already has a large supply of bolts, mags being made for them.

When I first heard about the 6.8 SPC back in 2003, I also thought that necking up the 5.56 case to take the 6.8 bullet would be a better way to go. Almost the same effectiveness as 6.8 SPC, but without the drawbacks of requiring new bolts and magazines. Trouble is, interference between the mag's front reinforcing rib and the larger case neck diameter (compared to 5.56) screws up cartridge alignment and stacking in G.I. mags, so it's still necessary to acquire new, cartridge-specific mags. The only benefit of using 6.8x45 is that a new bolt isn't needed.

I considered that possibly shortening the case to ~41mm length would permit using 5.56 mags ( http://www.angelfire.com/art/enchanter/bullet.html#270arc ), but I'm not sure if that would work as I didn't assemble enough 6.8x41 (6.86 ARC) dummy rounds to test for stacking.

 

[constructor]

J,
The powders could be faster than the 6.8s overall, Win 296 and 4227 were at the top of the list.

If new mags are needed then it would not be worth it for just the bolt and the 6.8 is hitting velocities we need to defeat armor.

 

[marinesg1012]

I am going to stick to the 6.8 SPC