AMU testing 6.5 based on Carcano case

[woohoo]

Edited- Sorry another false lead. It was presented at a the CTTSO meeting this last week but that doesn't mean it's going anywhere.


Seems the AMU is testing a 6.5mm based on the Carcano case. They are calling it the 264 USA.

The vague description just said between the AR15 and AR10 in length. It would be a good fit for a DMR or LMG round.

I know this has been talked about before but this didn't come from the internet.

[shooter545]

They have been for over a year now and recently briefed it at the TSWG AIM conference as well another.277 cartridge. Pretty interesting stuff.

[woohoo]

They have been for over a year now and recently briefed it at the TSWG AIM conference as well another.277 cartridge. Pretty interesting stuff.

The CTTSO last week? I wonder who was presenting it. I was asked to talk about my 2 designs in 6.5 and 6.8 but couldn't get all the data together fast enough. There were a few rumors out last year but the email I received Fri was from SOCOM HQ. The timing of that seems to be the connection.
Now I would like to see all the details to estimate the performance.

[lilharcher]

I assume you got this from H at 6.8 forums:

Here is the info from the source:
It seems the AMU is testing a true mid length cartridge based on the Carcano case .450" dia. The overall length is apx 2.5" it will be very interesting to see where this goes. Would be perfect for a DMR or LMG. Last year I posted this design. I wonder how close it is to the design being tested.

[woohoo]

I assume you got this from H at 6.8 forums:

Here is the info from the source:
It seems the AMU is testing a true mid length cartridge based on the Carcano case .450" dia. The overall length is apx 2.5" it will be very interesting to see where this goes. Would be perfect for a DMR or LMG. Last year I posted this design. I wonder how close it is to the design being tested.

I am H. incognito, of course everyone here knows that now.
I am trying to find out the specifics of the cartridge to estimate the performance. I have a few emails out to see where this is going.
the good thing is that this rumor from 2012 has been verified by someone in SOCOM.
This cartridge isn't one that would be used in 3 gun and it really isn't a sniper round when they have others they could use. The way I see it there is really only one use and that is why I'm interested.

[LRRPF52]

Would make a great replacement for 7.62 NATO. Get rid of the insane weight machine guns and cut the SASS weight down by at least 5 lbs.

A 45mm case would allow use of an expanded M27 link. Throw in a projectile with BC in the mid .5__'s, and you have over-match against 7.62 M80 and 7.62x54R.

Keep the pressures low, use purpose-built propellant for optimal burn time across the temp ranges, and it would be great.

[woohoo]

I received an email that cleared up some things. It appears the AMU is still pushing the same cartridge, it has apx 40gr cap. The person from SOCOM said the performance is good (better than the 308 with less weight)but the AMU guys did not consider the case taper and feeding issues. The case must have taper like the 308 to feed well from MGs. He thinks if it had the taper it would make a great LMG round. Also that the 338 Norma should become the new mounted MG. I don't think the 264USA is going further, at least not the design he saw but a similar version could. I was hoping that this was moving forward. Now I wish I would have gone with the Nexgen and 2 cartridges.

[stanc]

The dimensions noted in lilharcher's post indicate that the .264 USA looks like the 6.5x43* GPC prototype, second from left, below.



*Although case length was listed as 43mm in the photo caption, comparison to the other rounds in the pic shows the case length is the same as that of the 5.56x45 round at far right.

[shooter545]

I'm pretty sure that it was tested and briefed as a proof of concept and not necessarily a final form cartridge, simply to explore some of the possibilities. Regardless I believe that they on the right track with a medium caliber cartridge.

[woohoo]

I'm pretty sure that it was tested and briefed as a proof of concept and not necessarily a final form cartridge, simply to explore some of the possibilities. Regardless I believe that they on the right track with a medium caliber cartridge.

I know of 6 more, different but similar cartridges being tested now. I was hoping the mil was really looking and testing but after the third email from him I know they aren't. I don't like asking people at SOCOM HQ questions but I should have before I started this thread.

[JASmith]

You know that a new military cartridge will ignite another 60-year debate!

[stanc]

I'm pretty sure that it was tested and briefed as a proof of concept and not necessarily a final form cartridge...

Proof of concept could be much more easily done using downloaded 6.5 Creedmoor or 6.5x47 Lapua ammo.

It seems to me that if the AMU was going to the effort and expense of creating a completely new cartridge, they'd have given it the correct case taper so it could be demonstrated in machine guns. That's what Cris Murray did with his 7x46 UIAC.

Regardless I believe that they on the right track with a medium caliber cartridge.

I'm not sure that such moderate-velocity rounds are the way to go. Some fairly knowledgeable individuals think that the proliferation of hard body armor will pose a threat in the relatively near future. If this is true, the ability to defeat such armor may call for a much higher velocity round -- and possibly of smaller caliber -- than the 6.5-7mm cartridges currently being proposed.

[woohoo]

Proof of concept could be much more easily done using downloaded 6.5 Creedmoor or 6.5x47 Lapua ammo.

It seems to me that if the AMU was going to the effort and expense of creating a completely new cartridge, they'd have given it the correct case taper so it could be demonstrated in machine guns. That's what Cris Murray did with his 7x46 UIAC.

I'm not sure that such moderate-velocity rounds are the way to go. Some fairly knowledgeable individuals think that the proliferation of hard body armor will pose a threat in the relatively near future. If this is true, the ability to defeat such armor may call for a much higher velocity round -- and possibly of smaller caliber -- than the 6.5-7mm cartridges currently being proposed.

Exactly, that is why we were pushing the 85gr 6.8bullets so hard.
We tried to get Art to make 85gr frags,otms and 85AP so all 3 would have apx the same exterior ballistics. They ended up with a 97gr AP that would defeat L IV armor at 100yds. L IV will stop 308 and 30-06AP rounds. Speed is the key to defeating armorbut it must have enough mass to push through. M193 lead core does better against 1/2" plate than steel core M855.
Stan, you'll see my post on the other forum..".6.5 is it" they aren't changing calibers any time soon.

[shooter545]

Good points all.

[stanc]

Stan, you'll see my post on the other forum..".6.5 is it" they aren't changing calibers any time soon.

US mil in search of- PDW less than 6lbs, less than 18" long-CC, 5.56x45 cal

I guess that 18" length requirement rules out the Colt SCW.

[woohoo]

I guess that 18" length requirement rules out the Colt SCW.

yes, target is 16" and 5lbs but 18" and 6lbs is max. The SCAR PDW with a 6.75" barrel is too long.
There were 8 pages of things they are looking for. After reading it some seem more important than firearms but we tend to focus on the firearms. Seeing the arms requirements tells me they have no plans to change calibers anytime soon.

[stanc]

In case it's of interest, I happened upon a photo of Harrison/woohoo's Carcano-based 6.8x45 cartridge (second from right, below):

[stanc]

Happened upon a notice of solicitation for .264 USA cartridge cases:

https://www.fbo.gov/?s=opportunity&mode=...e&_cview=1

[stanc]

From the IAA forum:

"The .264 USA is one of the intermediate cartridges that will be tested in the current lightweight ammunition program, which also includes 7.62x51, 5.56x45 and a new .277, all using polymer cases. The proposed shooting plataform for those two new calibers is a AR-10 type rifle."

[stanc]

From: https://www.bids.tswg.gov/TSWG/bids.nsf/...4_TOS.pptx

[COLOR="blue"]Lightweight Intermediate Caliber Cartridges (LICCs)

Load and deliver mature test sample ammunition of 264 USA and 277 USA cartridges with lightweight (threshold); polymer (objective) cartridge cases with Sierra HPBT "MatchKing" projectiles.

Cartridges will function in modified, purpose-built AR-10 rifles and magazines in the semi-automatic and fully automatic modes of fire with and without the use of a muzzle-mounted signature suppressor.

Accuracy: 1.5 MOA (threshold); 1.0 MOA (objective) to 600 m (threshold); 800 m (objective).[/COLOR]