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Sturgeon's House

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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I'm dubious.  British post-war arms development seems far more influenced by the FG-42.  Like the Americans, the British loved them some FG-42:

 

This is the Korsak EM-1, not to be confused with the other British bullpup automatic rifle that is also called EM-1:

 

Early-bullpups-13.jpg?resize=930x870%3E

 

Mechanically it's just a bullpupped FG-42, according to Collector's Grade Death from Above.

 

Sadly, the Collector's Grade book on the EM-2 is stratospherically expensive, having been out of print for many years and is also not very good.  It's thin, does not cover the material in a methodical manner, and wastes several pages reprinting word for word a rant by a British Communist biologist about giraffes.

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See, I'm not sure that that is the case at all. Your average wood clocks in at 0.7g/cm3, while raw nylon is around 1.1g/cm3. Reinforced plastics are even heavier.

No condescension either, I'm just explaining things carefully and not assuming that the audience all has the same material science knowledge as myself.

Fair enough, I did snap at you a bit. Regardless, these plastic guns tend to be heavy because their designers don't understand that a bigger rifle is a heavier rifle.

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The EM-2 Wikipedia article is polluted by someone claiming the Sturmgewehr influenced it. Or at least the "intermediate" cartridge.

Jajajajajaja

https://en.m.wikipedia.org/wiki/EM-2_rifle'>https://en.m.wikipedia.org/wiki/EM-2_rifle

According to my sources, the program that resulted in the .280 British was explicitly intended to be a performance improvement vs. the KzPtr 43.

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You can reaction injection mold fiberglass, but the cycle times are slower than thermoplastic injection molding due to cure times. Cycle times go down further if you want a proper fiber layup.

From what I understand, fiber-filled plastics aren't a huge PITA compared to regular plastics. You do need to dial in the cycle time, temps, etc, for ideal dimensional consistency, but that's the case with un-reinforced plastics too. The biggest issue is the abrasiveness of the glass fiber on that very expensive mold.

Do you have some materials property data sheets for fiberglass to compare with fiber-filled plastic? Just how much better are these things supposed to be?

The main issue with injectable reinforced plastics that I've heard about is that they don't play nice with your nozzles. I will happily be corrected on this, however.

Per material properties; my main reference is back at the office but you infer the relative properties by comparing chop strand gfrp with weave. Weave is, needless to say, much better for a similar proportion of glass:

https://en.m.wikipedia.org/wiki/Fiberglass

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I'm sure they tear the shit out of nozzles, but nozzles (and screws and lots of other stuff) are usually cheap compared to the mold.

 

The high-tolerance parts of the mold are made with EDM, which is spendy.  It's not unusual for the mold to be as expensive or more than the injection molding machine it's strapped to.

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I'm sure they tear the shit out of nozzles, but nozzles (and screws and lots of other stuff) are usually cheap compared to the mold.

The high-tolerance parts of the mold are made with EDM, which is spendy. It's not unusual for the mold to be as expensive or more than the injection molding machine it's strapped to.

Yup. Unless you go for an aluminium one, in which case enjoy your 10 000 maximum units.

The best possible material I can think of would be something like a tri-axial glass/carbon weave in epoxy, constructed as a sandwich (core tbd). You could make damn near the whole gun this way.

Edit: they also clog nozzles, which is way worse.

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Well, I feel silly since everyone here evidently knows more about materials science than I do.

In other news, SHOT Show day 2 went unimaginably well.

Looks like someone hooked up with the Russkie show girls and invited them to the tank demo show.

Or else you got your grubby hands on some obscure cartridge that no one has heard of.

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I'm sure they tear the shit out of nozzles, but nozzles (and screws and lots of other stuff) are usually cheap compared to the mold.

 

The high-tolerance parts of the mold are made with EDM, which is spendy.  It's not unusual for the mold to be as expensive or more than the injection molding machine it's strapped to.

While glass fiber reinforced plastics will wear more on the nozzle and screws than normal plastics, it's not that bad. With the production runs of firearms, it shouldn't be a problem at all. 

 

I know for a fact that the mold of the grille of an Audi R8 (the part that's chrome plated) costs over half a million euros. I've visited various factories, and one that made bottles stored their molds in a fireproof bunker/room. The machines themselves weren't all that well protected. Granted, moving a machine isn't something you'll do, but still. It wasn't so much due to the production costs of the mold, but more due to the molds being the only one of its kind. If they threw a mold away, and had to do a re-run of that part, the new mold would have slighly different dimensions from the old mold. They didn't want to risk parts not fitting properly.

With weapons you don't have these problems because you won't make millions of parts on one mould anyway.

 

 

I've decided to ban posting shit from /k/, because /k/ is shit.

k

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.50 BMG rifle, gift courtesy of the ATF, recovered in El Chapo raid.

 

This will have a very negative impact on American foreign policy.  Imagine now, someone in the State Department trying to upbraid the Russians about human rights or transparency.  They'll get some response like:
 

 

"Yes comrade, our government is of corrupt.  Is very sad.  As you know, living under corrupt government that gives guns to drug cartels for reasons they cannot be bothered to explain is sadness.  Oh well, perhaps commiserate with vodka while we invade former satellites?  Or maybe we bomb Middle East; that is what Americans do for recreation, da?"

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So? You gonna bitch about me talking about guns, just because they're on /k/, too?

 

no, i am gonna bitch when you bitch about someone putting something more gun than humor related on this specific thread, and having it shot down because "le /k/ meme'

 

bitchception 

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Stop it, this is silly.

 

 

New CZ stuff:

 

DSC02742_zps9stzwkts.jpg

 

NFA rules make for really silly looking pistol caliber carbines.

 

DSC02737_zpsjjil9plm.jpg

 

Cz 805 post '86 dealer samples.  Gotta wonder how many of these CZ is trying to move while they get the 806 moving.

 

If you look at the shape of the upper and lower, you can see that the 806 is a completely new rifle:
 

cz_806_bren.jpg

 

I'd wager that the 806 has an extruded upper receiver, like most other SCAR-clones.

 

The SCAR-clone is rapidly becoming the new Glock-alike, but for rifles.

 

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