New Cartridge Developments and Implications for Dismounted Infantry Soldiers

[stanc]

Otherwise, I need to try some of the 140gr military-compatible bullets that are available in my .260, and I'm having a hard time finding them. I just checked Midway, but couldn't find any 140gr 6.5mm FMJ's. I wonder if we could locate a source for just the 140gr Swedish military projectiles, separate from the loaded cartridges.

Midway offers the Lapua 144gr FMJ.

I don't know of sources for Swedish military 140gr FMJ bullets only. If you specifically want such, probably have to buy mil surplus ammo and pull the bullets.

The S&B site does show that they have 140gr FMJ projos (in boxes of 100), but I couldn't find a source for these in the US. Also, they look to have a slightly rounded tip, where the Swedish mil bullets are much more pointed.

http://www.sellier-bellot.cz/ammo-components-bullets.php

Wolf and Prvi market 6.5x55 w/139gr (flat-tipped) FMJ.

[LRRPF52]

stanc,

Thanks for that. I just requested some sourcing for those Swedish Military 140's via contacts in Finland. That's a pretty popular cartridge over there, and Europe as a whole of course. I'm looking at the 6mm BR, which has a water capacity of around 38-39.5grains. I'm thinking a more ideal cartridge for what we're looking at would have a narrower base diameter like the Grendel at .444", with more cartridge length for powder capacity, and would give a better over-bore relationship for barrel life if used with a .264" bore. Basically, a longer base-to-shoulder Grendel would seem ideal at this point, given that we aren't limited by mag-length. If closer to 40 grains of powder could be used, that would get the 6.5's going much faster.

The .260 is way too spacious in case capacity for long bullets at least, and a slightly-narrower case would help with barrel life as mentioned, in addition to soldier carrying capacity for space.

LRRPF52

[stanc]

I'm thinking a more ideal cartridge for what we're looking at would have a narrower base diameter like the Grendel at .444", with more cartridge length for powder capacity, and would give a better over-bore relationship for barrel life if used with a .264" bore. Basically, a longer base-to-shoulder Grendel would seem ideal at this point, given that we aren't limited by mag-length.

6.5x45 Czech?

[Tony Williams]

Basically, I'm thinking of testing the 140's versus the M80 ball at 500m, 600m, and 700m on some common mediums. Then we could work backwards in bullet weights with 6.5's if the 140's prove superior to the 147gr 7.62.

That sounds great, but it might be as well to spread the ranges somewhat to give a more complete picture: something like 200m, 500m and 800m. Logically, the performance of the 6.5mm relative to the 7.62mm should get steadily better with increasing range.

That 6.5x25 is an answer to all my concealed carry dreams.

One of my favourite guns is the B&T MP9 in 6.5x25. I had the chance to shoot it in Sweden a couple of years ago (Carl-Bertil Johansson invited me over, because I had suggested that it might be a good combination). I wrote an article about it which was published in the Fall 2010 Small Arms Defense Journal. There's also a brief note about it at the end of this article: http://www.quarry.nildram.co.uk/PDWs.htm

I have that piece of armour with a hole blown through it on my desk (see below):

[Tony Williams]

6.5x45 Czech?

Or, to put it another way, Cris Murray's 7x46 necked-down to 6.5mm?

[stanc]

Or, to put it another way, Cris Murray's 7x46 necked-down to 6.5mm?

That, too.


I wonder if Murray is still working on the 7x46 project? Last I heard -- about a year ago -- was that he was starting to convert an MG42 to fire the 7mm UIAC. But, his web site seems to no longer exist, and a search only turned up this year-old article: http://www.thefirearmblog.com/blog/2...ult-cartridge/

[Tony Williams]

I wonder if Murray is still working on the 7x46 project? Last I heard -- about a year ago -- was that he was starting to convert an MG42 to fire the 7mm UIAC. But, his web site seems to no longer exist, and a search only turned up this year-old article: http://www.thefirearmblog.com/blog/2...ult-cartridge/

I met Cris last year at NDIA, and last heard from him in November when a test of his converted MG 42 was imminent. I've sent him an email to enquire about progress.

[Tony Williams]

I've heard from Cris. He's fine and trying to finish a prototype assault rifle. Microsoft stopped his Windows live web service and he hasn't got around to replacing it yet, but he's happy to answer question directly.

He'll be at the Indianapolis NDIA meeting next week, if anyone's going (I won't be this year).

[LRRPF52]

Tony,

Do you know if Chris worked at the AMU at Benning? Was he ever in the National Guard? This guy sounds a lot like someone I knew who was involved with the 6.8 SPC development, but I lost his contact info. You can PM the response.

The 7x46 would seem ideal for a case, pushing a 6.5 of sufficient weight at a sufficient velocity to give good downrange performance. It would require strong brass, and if a small rifle primer could be activated reliably in extreme cold weather conditions, that might be the ticket.

LRRPF52

[Tony Williams]

I've PM'd you.

[LRRPF52]

Gents,

Reading about the 7x46mm some more, it looks like the choice of 7mm might have something to do with the pressure limitation objectives of keeping it under 50k psi with a 130gr going 2650 fps out of a 16.5" barrel, which is a sensible objective for a repeating rifle or machinegun.

A 6.5mm would add a lot more pressure than a 7mm due to the increased bottle neck, but it remains to be seen what characteristics this 46mm length case with a narrower base would have. It's worth looking into I think.

LRRPF52

[BluntForceTrauma]

LR, yes, the Cris Murray in question, with the 7x46, is also the one involved in 6.8 development.

John

[LRRPF52]

I've emailed back and forth with him. He has converted that MG42/3 to 7x46, and is using non-disintegrating metallic links from the RPD I think. He has a good sense about managing the pressures at lower levels to keep longevity for the firearms and component parts. The 7x46 has less over-bore, so it is lower-pressure, with less recoil.

He also has an assault rifle design roughly worked-out with some 3D drawings.

We both agree that there should be a test and evaluation board of engineers with combat arms backgrounds, who will actually have to deploy to hostile-fire zones with any new designs before giving a stamp of approval, rather than the retired Colonels and Generals who have to train their gag-reflex not to function when they push whatever company's horrible products as a lobbyist or contractor to grease the Pentagon system. It's pretty much SOP in that demonic town of D.C.

I saw a lot of it first-hand when I was stationed there, especially at AUSA and other conventions. A guy with a huge salary that was an O-6 or above retires after 25 years on active duty, jumps right into work for one of the numerous defense contractors, drinks the company cool-aid after seeing his salary, and pushes whatever system they are selling like it's good as gold.

A few years later, when I was in LRS, we had these defense contractor types come issue us some silly field heater pack gizmos, and they mentioned that they had been involved with the LBV design. I proceeded to let them know what a piece of crap it was with the maybe 300 denier fabric it was made of, the tiny mag pouches that could only hold a candy bar or pens after being soaked and dried, and some other issues with it. One SGM (Ret) who was part of this committee tried to tell me how those inboard pouches were set-up for lying in the prone, and that they didn't need to be capable of holding two mags. I had already cut them off of mine and sewn on some 1000 denier Cordura Woodland Camo GP pouches that could hold plenty of mags, SAW ammo, 203 rounds, NOD's, etc. regardless of what duty position or weapon system I needed to fill.

Anyway, an active prototype and field test engineer team would really make a lot more sense. Have students in Ranger School and the Q-Course evaluate products after that for durability, and then make necessary improvements. The PEO system is pretty weak, if you ask me. I looked at their site recently, and they couldn't even get the nomenclatures correct on their own systems, which were in the hands of Military District of Washington soldiers in pristine kit. The new systems seem to be bulkier and heavier than what they're replacing, especially the grenade launcher that is supposed to bump the 203 out of the system. Major fails...

LRRPF52

[Mav714]

What's amazing to me is that my dad and other relatives carried either the Garrand or .30 carbine all over WII and got the job done. Countless soldiers carried the 30:06 all over with a 9+ lb rifle plus the gear. what I especially don't understand about our military is why they want to stay with a varmint round. I know it's a NATO round etc, but putting combatant down quickly vs multiple shoots doesn't make sense. Don't even get me started on the 9mm vs the 45 acp! Once again a heavier bullet will do more damage as well stop a vehicle.

[JASmith]

Mav714,
You've nicely captured the essence of the debate!