Monday, December 06, 2010

Stepping boldly into the 1930s...

The four-column magazine is not really anything new, of course. I had a SITES Spectre pistol back in the mid-'90s that ate out of 30- or 50-round sticks, and the concept's use in modern firearms apparently runs back at least to the Finns and Argentinians in the 1930s.

The metallic cartridge firearm is really very mature technology, and there is very little new under the sun.

Nice idea, but I'm guessing that the point where the 4 columns turn into 2 will bind up something fierce when sand or debris gets in there. The Finns got rid of their Swedish coffin mags for similar problems, I believe. I read that regular double stack magazines that feed from a single position tend to suffer from the same thing.

Judging by the illustrations, the followers on the AK mags had to perform some strange contortions at that point too, which probably doesn't help matters.

And yes, what Matt G said -- great post! I knew almost nothing about the HAFDASA burp-guns before this.

Tam; another problem with caseless is how do you EXTRACT the round when it fails to fire??? I know some are presently attaching a brass base with an extractor groove to their 'caseless' ammo, but that more or less defeats the purpose of the whole thing, doesn't it?

Personally, I'm waiting for perfect electrical conductivity at room temperatures; then we will be able to man-portable rail gun technology off current battery techology.....titanium needles at HYPER-Velocities???

Or one of Luke Campbell's portable laser designs-see http://www.projectrho.com/rocket/sidearmenergy.php#Design~Luke_Campbell's_Lasers.

I'm especally fond of the "battle laser". In his words"The beam energy is 10 kJ per shot, made up of 50 pulses of 200 J each, spaced 10 microsecond apart. This puts each pulse in the range of a big firecracker. The total beam energy is about the same as a .460 Weatherby magnum bullet..."

The quad column mag looks interesting, but I'll pass. Would be fun in a full auto, but to me, I see the following barriers to adoption:1) A 60 round mag is the same price as TEN Pmags (or other quality 30 round STANAG). 2) When it breaks, you're out a lot of cash. If it chooses an inopportune moment to break, a large amount of your ammo load out just crapped out on you.3) Weight... these rifles are getting heavy enough without doubling or tripling the weight of the ammo loaded in.4) It's going to take forever to load. Spring tension seems like it's also likely to be fairly epic if it's going to be powerful enough to present a round for feeding fast enough when fully loaded.

Now, there's times when one might be nice (as I said, full auto, and then in a defensive situation), but even if I channel my inner mall ninja and crank him up by a couple orders of magnitude I'm not sure I could convince myself to get one.

And yeah, it seems like everything new in the world of firearms lately is mostly revisited ideas with new manufacturing materials and techniques. Not that there's anything bad about that, but you're right Tam- the modern firearm is a very mature technology, and it would take a major leap forward (directed energy weapons, for example) to really make current designs obsolete.

With current technology, a liquid propellant gun that has performance similar to solid propellant guns is most likely possible.

I imagine that if compressed pure oxygen was used, it wouldn't be a problem to make a high performance liquid propellant gun. After all, diesel has ten times the energy density of TNT . Anything in pure oxygen burns very rapidly. Injected under high pressure, the chamber needn't be very large.At 100 atmospheres, one cubic centimeter weighs ~ 0,15 gramms..

...so, 2 gramms of diesel with 8 gramms of oxygen could all combust in a spherical chamber no bigger than 2 inches in diameter.

Now, 2 gramms of diesel give about 100 kilojoules when burned. Even if only 10% were utilized to power the projectile, it'd have a kinetic energy of 10 kilojoules...

Sure, such a gun would be a fire hazard, heavier than current guns, and it'd be harder to achieve constant muzzle velocity due to temperature changes..

I used to think like Aussenseiter, but all the solid stuff I've heard about in trade bull sessions or read of in industry journals about liquid fuel leaves me to think it can't scale safely, and actually isn't much more than a liquid form of caseless with the problems of sealing wildly increased.

The stuff is scary dangerous to handle, and has all kinds of dangerous and exposed tankage, valves, and tubing.

The oxidiser, in addition to being corrosive as hell, makes it bulk up to proportions quite similar to smokeless powder.

I gather the biggest operational problem they have, after the fact that the metering and sealing elements get eaten away at a foolish rate, is that pulling a charge often results in a life threatening situation. Bad enough in a go-down at Ft. Sill, suicide in a counter-battery situation on the battlefield.

What Frank James said. Railguns with fin stablised darts, someday in the future.

I still have a couple of SPECTRE magazines in 9mm, from the time, about 5 years ago, when I was doing some R and D work for Mack Qwinne, up at MGI in Maine.

He was thinking that, since the 5.56mm and the 9mm parabellum have essentially the same head and extractor groove, we could lenghten it and make a 4 into 2 mag for the AR.

Again, it didn't scale. No way to control the longer cartridge. We just couldn't stabilise the frigging follower(s).

Also, we made up a bushing for the SPECTRE and shot it in a Colt 9mm rock and roll carbine, and it's performance in the original 9mm was less than stellar. A lot of energy lost to friction in the merges, even when they're thought out pretty well (and the original wasn't).

Split followers have their place. The setup Barry Bergin uses in the CProducts 5.45mm AR mag he makes for Smith & Wesson is amazing in it's simplicity. Something about the devil being in the details. I remember what he went through to make his contract deadline, and it wasn't pretty.

Bottom line is that smokeless powder is about 93% efficient, essentially identical to liquid propellant, without the strong chance of the breech erupting.

The primary interest the artillery boys had in it was the ability to choose the charge with a simple push of a button. They've long since decided it isn't worth the risk.

High pressure oxygen isn't exactly 99% nitric acid.. and a variety of oxyacetylene torches are sold quite cheaply.

@Tam..Sure, it's fairly obvious. I think it's been patented in like.. 1915 or so. No practical implementation so far. The thing is that designs that used to be impractical or uneconomical in the past are possible now that CNC machining enables good precision at lower prices.

BTW, there already is a liquid fuel gun, in prototype phase it seems.http://www.popularmechanics.com/technology/military/weapons/toymaker-turned-weaponmaker

More of a stun gun, though, and it seems sort of dodgy. It doesn't have extra oxidiser, which makes me wonder about the power output.

Caseless seems to work great; in low velocity, low pressure designs if the 9mm AUPO and Russian 40mm grenades are anything to go from. It's only when you want to do something silly like make a caseless rifle cartridge that the sealing, thermal and ammo integrity start being serious problems.

Of course, there are barely any weight savings in the low-pressure, low velocity side of things since a cased design would have been pretty small and compact anyhow.

The only reason those things sell in places like Russia is because people want guns.

If you seriously want to deliver OC or CS on a target, a 9mm projectile is about the most useless way to do it I can think of, which is why nobody other than unarmed Russian civilians uses the damn things. It's a lot more efficient to use an aerosol spray or, if you need range, something like an FN303.

"I don't mind agreeing with you on occassion, but here the cause seems to be insufficient caffeination on your part."

Or perhaps I was just reading past you? ;) Sorry, 'bout that. We obviously both enjoy arguing on the internet, and this time I was apparently too eager to joust.

Anyhow...

Yeah, baton rounds from a 12 gauge are unpleasant; the concept doesn't scale down well, but I guess there's no need for a marketing department to point that out to some poor Russkie buying a 9mm wheelgun.

No, not caseless. I think plastic-cased is way more promising, but the innovation I was talking about was mostly things like electrically-driven actions, electrical priming, that sorta thing.

One thing that is pretty consistent is that if something is widely used in aircraft guns, it'll probably trickle down and be used by infantry rifles sooner of later. Red dot sights are essentially the same thing as reflector sights from WWII, for instance.

"One thing that is pretty consistent is that if something is widely used in aircraft guns, it'll probably trickle down and be used by infantry rifles sooner of later."

Generally, yes.

The big difference being that a/c guns are rarely required to perform after being submerged in frozen slush at the bottom of a shellhole; witness the 70-year gap between WWII reflector sights and the first red dots rugged enough to serve on serious infantry rifles...

Personally, I think the next step lies in a weapon where the driving mechanism is water with a little electrolyte, in a plastic capsule attached to the back of the projectile.

Feed a capacitor-stored burst of electricity into the capsule and watch the bullet go... or not watch, as you could dial in pretty much any velocity you wanted up to the maximum of the system, though I'd recommend keeping the minimum at or above the level where all the water is vaporized and expelled.

As a bonus, capacitors light/dense/rugged enough to power such a beast would serve wonderfully in the pumping circuits of any laser weapons to follow.

Also, if you have a laser, could you not mince/mix tech and have an 'attachment' with a laser target built into a large projectile i.e. grenade, to slip over the 'muzzle' and blast over the top of your enemy's shielding? It'd be like a bullet trap grenade, but furnished with a vented tube stuffed with "magic soot" or whatever color powder absorbs the laser beam best, vaporizes, and via reaction lobs the thing skywards...