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Old 11-08-2017, 10:23 AM   #11
malloyd
 
Join Date: Jun 2006
Default Re: Making more ammo stuck on a low tech world.

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Originally Posted by Fred Brackin View Post
Making brass from scratch would indeed be difficult. One page I googled a few years ago had it be a 17 step process with multiple forming dies and 3 trips through an "annealing oven" which I'm not quite sure what is. Some sort of heat treatment.
For brass you do that to relax the work hardening (which all copper alloys suffer from). It's not a real precise target temperature, several hundred degree range for brass, though of course the minimum time you need to hold it there is temperature dependent.

Annealing is usually something you do to relax internal stresses like work hardening in metals or differential cooling in glasses, though it presumably means something different in iron metallurgy.
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Old 11-08-2017, 11:08 AM   #12
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Default Re: Making more ammo stuck on a low tech world.

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Originally Posted by AlexanderHowl View Post
Modern firearms do not use black powder and the rifling would probably erode quite quickly due to the acidic nature of the remnant propellant (shotguns are probably the only exception). Current propellants of nitrocellulose (single-base) or nitroglycerin and nitrocellulose (double base) and neither of them are going to be produced outside of a late-TL5 industrial base.
People have been making nitrocelluose since the 1850s, and the primary components (nitric acid and sulfuric acid) have been made since at least the 13th or 14th century. It doesn't look like it would be that hard to make in small batches, though it might be time consuming to start from scratch.

Setting up a full chemical plant with Ostwald and Haber processes so you can make enough nitric acid for millions of rounds probably requires a late TL5 or TL6 tech base. But if you only need 1 lb of nitrocellulose - which is 7000 grains of powder, enough for 100 or so rifle bullets - you can probably do that with stuff made from a TL8 Factory module and a couple of weeks' work in a lab. Making ammonia at 4 oz/hr is going to be tedious, but 6 pints of the stuff should hopefully be plenty for both the nitrocelluose and the mercury fulminate.

Are the kinds of brass cartridges, mercury fulminate primers, and nitrocelluse powder that a single guy makes in a lab going to be of less than commercial quality? Sure. Would I expect to see a lot more misfires and corrosive gunk in the barrel? Definitely. Is it better to have 100 somewhat unreliable bullets than 5 reliable bullets? I'd expect so.
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Old 11-08-2017, 11:20 AM   #13
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Default Re: Making more ammo stuck on a low tech world.

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Originally Posted by Kfireblade View Post
Assuming the character had access to a large vehicle (SM+7) with the TL 8 Mining and Factory systems from spaceships what would they need to find, and how hard would it be?
So one thing that hasn't been mentioned so far, but that is relevant, is that a lot of the chemistry works best when the chemist has access to abundant levels of electricity and/or heat. Depending on how much stuff he wants to make and how his vehicle is powered, one the steps might be "drill for oil, make a dirty-tech refinery (High-Tech p 16)". This is less of a concern if he's a time or space traveller with a fusion plant on his vessel, though you still might want to do some fractional distilling of petroleum to get useful feedstock chemicals like methane.
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Old 11-08-2017, 12:30 PM   #14
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Default Re: Making more ammo stuck on a low tech world.

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Originally Posted by mlangsdorf View Post
So one thing that hasn't been mentioned so far, but that is relevant, is that a lot of the chemistry works best when the chemist has access to abundant levels of electricity and/or heat. Depending on how much stuff he wants to make and how his vehicle is powered, one the steps might be "drill for oil, make a dirty-tech refinery (High-Tech p 16)". This is less of a concern if he's a time or space traveller with a fusion plant on his vessel, though you still might want to do some fractional distilling of petroleum to get useful feedstock chemicals like methane.
The vehicle is equipped with a nuclear reactor, but drilling for oil is on the to do list.
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Old 11-08-2017, 12:34 PM   #15
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Default Re: Making more ammo stuck on a low tech world.

US Army Technical Manual TM 31-210 Improvised Munition Handbook gives instructions for hand reloading cartridges using chemicals improvised from a variety of low(ish) tech sources. It also warns that the products are unreliable and a good way to blow one's self up in the long run.
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Old 11-08-2017, 12:39 PM   #16
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Default Re: Making more ammo stuck on a low tech world.

There was a similar question asked a while ago, here. It has a fair bit on primers, as does this thread about ATE firearms, though it degenerates (very strangely) into a crossbow fan trying to convince everyone else of his agenda. Together, they have a lot of information on what you want, from some of the GURPS Forums gun gurus, who I am surprised have not shown up here yet.

Last edited by acrosome; 11-08-2017 at 01:24 PM.
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Old 11-08-2017, 12:40 PM   #17
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Default Re: Making more ammo stuck on a low tech world.

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Originally Posted by mlangsdorf View Post
What kind of weapon do they want to reload? A Spencer rifle firing black powder cartridges is a different problem than a G11 firing caseless than a UT ETK gun.

Assuming you want metallic cartridges, you're going to want:
* Lead or iron or copper, for the bullet
* Brass, iron, or bronze (copper and tin), for the cartridge itself
* Mercury, nitric acid, and ethanol, for the primer
** nitric acid can be made in various ways, but the modern industrial process uses ammonia as a feed stock and requires platinum for a catalyst; you can also use saltpeter, alum, and copper sulfate
** You can use potassium chlorate or potassium perchlorate instead, which require various potassium and sodium chemicals and are more difficult to make

Black powder is made from sulfur, charcoal, and saltpeter. You extract it from bat guano, mine it from fairly rare natural deposits, or synthesize it from nitric acid.

Smokeless powder can be made lots of different ways, but guncotton can be made from fine fabric threads, nitric acid, and sulfuric acid.

Caseless and ETC rounds are a lot more complicated, but it's basically the same stuff with some more exotic variants.

None of the chemistry involved is crazy hard or exotic: all the components were made by the 1860s historically. A lot of them are fairly dangerous to handle (mercury, chlorine gas, mercury fulminates) but normal lab safety procedures should be enough to avoid serious mishap. You've got access to TL8 manufacturing, so you can recast bullets and cartridges to the necessary tolerances.

As for finding the components:
* lead, iron, and copper are fairly common on Earth and have been mined since antiquity.
* mercury, sulfur, alum, and tin are rarer but are not terribly hard to find
* ethanol can be distilled from just about any sugar source
* saltpeter can be extracted from animal waste, so as long as there are bat caves or domesticated animals, you should be okay. Alternately, you can synthesize it from nitrogen in the air IF you can find platinum for the catalysts.
* cotton or equivalent threads come from certain plants or animal hair

A lone man would be hard pressed to find, mine, refine, and combine all those components into a single bullet. A lone man with access to an early trading system, like the early Roman Republic or early Chinese empires, could get everything he needed and then would just need to refine and put the pieces together.

There's also a separate question of scale: hand crafting out 100 blackpowder shotgun shells for your personal use is a lot easier than manufacturing 1 milliion .30-06 rifle rounds to equip the Roman Praetorian guard.
I don't need caseless or ETK ammo, unfortunately I do want to go better then black powder. Now I actually am going to have a few tons of ammo and weapons with me in my cargo which will last awhile but not forever when I'm trying to build up a force. I do have access to a mid TL 4, early TL 5 in a couple places, infrastructure when it comes to trade.
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Old 11-08-2017, 01:20 PM   #18
Anthony
 
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Default Re: Making more ammo stuck on a low tech world.

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Originally Posted by Kfireblade View Post
I do have access to a mid TL 4, early TL 5 in a couple places, infrastructure when it comes to trade.
That simplifies things significantly, as most required feedstocks are available (if possibly requiring additional purification).

I would note, however, that TL 8 industrial machinery is specialized. It's certainly possible to have a refinery system that produces nitric acid and ammonia from air, water, and electricity (or several other ways of producing hydrogen, such as coal or natural gas); it requires catalysts that you probably can't make or replace at local tech, but they won't be any more of a problem than any of the other parts of your machinery that you can't make or replace with local tech.
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Old 11-08-2017, 01:40 PM   #19
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Default Re: Making more ammo stuck on a low tech world.

Out of curiosity, what is the exact TL8 weapon that this character is trying to feed? It will be a lot easier if it's a shotgun, frex, and some weapons might actually tolerate black powder as a propellant very well, especially if corned. Whereas e.g. an M16 absolutely will not...
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Old 11-08-2017, 02:03 PM   #20
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Default Re: Making more ammo stuck on a low tech world.

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Originally Posted by Kfireblade View Post
I don't need caseless or ETK ammo, unfortunately I do want to go better then black powder. Now I actually am going to have a few tons of ammo and weapons with me in my cargo which will last awhile but not forever when I'm trying to build up a force. I do have access to a mid TL 4, early TL 5 in a couple places, infrastructure when it comes to trade.
If you access to trading partners that can provide you refined copper, iron, mercury, and lead, as well as nitric and sulfuric acids, and you have enough wealth to buy the stuff from them, there's no reason you can't get all the raw materials you need. Then it's just Chemistry, Mechanic, Machinist, and Armory rolls to put everything together.

You can probably make the wealth necessary by buying the leftover slag from their precious metal mines and using your much more efficient Mining apparatus to extract even more precious metals from them.

The rules for making stuff with the Factory are on Spaceship 1 p 16. TL6 goods are 4 times as expensive at TL4 as they are at TL6, so .30 caliber ammo that costs $0.8 is going to have an effective price of $3.2 and require $1.5 in materials - you can crack out 5000 in an hour once you get going. That seems absurdly fast to me unless you have multiple assembly lines (and implies you can make a car in few hours...) but even a more reasonable 50-500 rounds/hour means that a day's work supplies you with a reasonable load of ammunition.
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