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The Small Arms Thread, Part 8: 2018; ICSR to be replaced by US Army with interim 15mm Revolver Cannon.


Khand-e

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Been thinking about hi-lo mixes for next-generation small arms ammunition, specifically the "hi" part of such a mix. One line of inquiry deals with the 8-8.6mm caliber range, but I also wanted to investigate the 7mm caliber range as an alternative. I've been playing around recently with a necked-down 7.5x54mm French to 7mm, with the case essentially providing a reference point for weight estimations. Capacity is 4.135 ccs, with a steel case. Operating pressure would be about 57,000 PSI.

I have designed a 134gr steel-cored lead-free AP bullet for it, which the dimensions given in the JBM BC calculation screenshot below. You can see their stability calculation for the round as well; I'm curious whether that's accurate or not.

 

MNSVpMG.png


JBM estimates its i7 FF at 0.938, which ain't bad. Its core is the same diameter as .30 M2 AP's core, but is 9% longer and 10% heavier. So the projectile carries a penetrator that is disproportionate to its size, and if the bullet proved feasible it would theoretically provide superior armor penetration to .30 M2 AP at comparable velocities.
 
lA0uU6O.png

With that bullet, the 7mm would according to Powley attain a muzzle velocity of 3,000 ft/s, which gives the round 950 meters of range above Mach 2, and a supersonic range of 1,130 m, according to JBM. It has at 1,300 m the same energy M80A1 has at 1,000 m, and retains the same specific as M80A1/1,000 m at 1,500 m. 
 
L0Udn5U.png
 
ACN3fQZ.png
 

Round weight would be 22.5 grams with a steel case or 24.8 with a brass case, very similar to the Russian 7.62x54mmR and 7.62x51mm, respectively, while round overall length (conventional cased) would be 3"/76mm. With a brass/polymer composite, cartridge weight would be about 20.5 grams. CTA 7mm is estimated to weigh below 18 grams.

 

hEIsYTK.png

 

The idea here is to try to get superior performance to 7.62mm, optimized for penetration and accuracy, with less weight than other solutions. A part of my brain thinks that going above 7-8mm caliber doesn't help very much, because fundamentally the projectiles being fired are inert, so it may be better to standardize a smaller, lighter caliber capable of doing the same jobs.

 

Like the Russian 6mm Unified, this would be a round designed only for the GPMG and marksman weapons, not for infantry rifles or squad automatic weapons. It's too big for that. I think though, if anyone has any reservations about the .338 caliber as the "big" caliber in a next-generation 2-caliber system, maybe something like this would help assuage that concern.
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What is this exactly?

 

I've sort of lost track of all of the nouveau-AKs.  I'm also fairly skeptical about the use of a stock AK bolt carrier.  Look, the AK was well designed for mass-manufacture... by the standards and using the techniques that prevailed in the 1940s in the Soviet Union.  Mikhail Kalashnikov was (probably) not the Kwisatz Haderich and could not see into the future.  Things are a bit different in 2016 anno domini; particularly as far as parts interchangeability goes.  Maybe if all of the bolt carriers are supplied from a single factory in a single country, they will be up to what US designers would consider standard tolerances.  But AK parts picked at random?  Um, no.  Even if they are excellent in all other ways, AK parts simply have more dimensional variation in them than, say, AR-15 parts.

 

Also, it's not like the AK bolt carrier is a particularly easy bolt carrier to manufacture by modern standards.  Sure, it's way better than the op-rod on a garand, but look at the idiot-proof stuff that has been designed since then:

 

H1Wkape.png

 

It's a friggen piece of steel billet cut to length with some holes and a cam track drilled in it!  It's much simpler than an AK bolt carrier:

 

sM6bc3t.jpg

 

And that goddamn FAL gas system.  Are people aware that there are, in fact, other adjustable gas systems out there?  Including designs that have a low propensity to distort under heat, unscrew themselves and launch themselves downrange, thereby converting your self-loading rifle into a bolt action?  If the FAL gas system was all that, why the hell doesn't the FNC use it?  On top of being more robust, you can actually use the FNC gas system without burning yourself!

 

I'm not saying the last 70 years in small arms design have been great, but there have been a few good ideas.  I don't understand the reluctance to use them.

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Not written by Christian Lowe - a good start.

His basic premise I - and others - agree with. However, he is a COMPLETE SHIT writer. This?
 

While Russia was hurriedly developing its first true assault rifle, the AK-47, NATO was still hung up on the concept of a battle rifle. Though this makes perfect sense in retrospect.

 

I call that the "gets a C in grade school" writing level. More:
 

The vaunted DMR bridges the gap between the M4 and dedicated sniping weapon systems like the M24.

 

The vaunted DMR? That's like saying "the vaunted pickup truck". Please, folks, read your writing out loud before you publish it.
 

Seriously, disturbing the gun’s bedding – the way it’s glued into a stock — doesn’t just shift point of impact; it reduces overall accuracy.

 

 

I mean, like, seriously, you guys, totally. What, was this written by a valley girl? I might use writing like this in a forum post, but in an article that I (presumably) got paid for?

15652797.jpg

 

In details, this guy's article is equally shit to Christian Lowe's amazingly bad list of weapons the military "should" bring back. This big, for example:
 

The one thing the M14 has going for it is its method of operation. It’s a long-stroke, piston-driven action that’s very similar to the most prolific assault rifle in history: the AK-47. Like the AK, the M14’s action can tolerate debris and fouling better than the direct-impingement M16. 

 

Been debunked scores of times going all the way back to 1940. I'm seriously:

http://www.thefirearmblog.com/blog/2015/02/20/the-m1-garand-dust-mud-1950/

http://www.thefirearmblog.com/blog/2016/02/24/tangofoxtrots-rifle-dust-tests-mini-14-aug-arx-100-scar/

http://www.thefirearmblog.com/blog/2015/12/23/inrange-gets-dirty-m1-garand/

http://www.thefirearmblog.com/blog/2015/02/05/inrange-tvs-heinous-m1a-abuse/

 



The M1 family cannot tolerate significant amounts of foreign debris, and can we PLEASE let go of this idea that having a "piston" makes your gun super duper reliable automatically?

 

Also,

 

Accuracy is a measure of consistency when it comes to rifles. Given that a DMR must, by definition, extend the effective range of a squad, its DMR needs to reliably hit targets beyond the reach of the infantryman’s standard rifle or carbine. Yet, according to military standards, acceptable accuracy from the M14 is 5.5 inches at 100 yards – a full inch larger than the M16’s standards. While the M14’s 7.62mm round is great for this, the gun is not.

 

Quoting the "military standards" you're talking about is apparently for suckers. What standards? Standards for the rifle? The ammunition? The shooter-rifle-ammunition combination? I agree that the M14 is not a particularly accurate rifle, but this whole argument is ignorant of even the way standards work

 

In all fairness, the Global War on Terror presented a combat theater the US military wasn’t prepared to fight in. Plus, the M14 wasn’t meant to be a sniper or DMR platform when it was developed in the 1950s. Even still, Armalite had been producing civilian and military AR-10 rifles since the late 1950s, and could have just as easily been pressed into service.

Better yet, since the AR-10 shares its method of operation with the M16, advancements on one could likely be applied to the other. And the guns shares the same manual of arms, so no additional training is required for soldiers transitioning from one to the other.

 

 

...Really? And who would have manufactured the AR-10 in the 1950s? Colt? They hadn't bought the design from Amalite yet. Armalite? They weren't set up for mass production of anything. Springfield Armory? They wouldn't have touched it, not with how vulnerable their own project (the M14) was during this period. How would this procurement have occurred, also? The US government had just spent millions of dollars and a great deal of pain and heartache to bring the M14 into production, and what, they were just going to abandon it?

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