A simple aluminum ram

[Swede]

I am currently exploring alternate propellants for muzzleloading firearms, and have been experimenting with KNO3, sucrose, and iron oxide compounds. This has been around forever as a rocket fuel, but I am interested in testing its performance as an emergency propellant for firearms. The goal was, and still is, chemical simplicity. Anyway, I was in need of a small ramming system, as handling moistened (not melted) KNO3/sucrose has been a nightmare. It's horrible, and very difficult to get good grains. I decided to try ramming some to see if driving out excess moisture prior to screening would help, as well as perhaps boost performance.

 

Aluminum tube is relatively cheap and easy to get from sources like Metal Express. I happened to have a short section of 1.250" ID tube, and like much available tubing, the bore is slightly smaller than 1.250"

 

http://www.5bears.com/firew/ram02.jpg

 

I first cleaned up the ends. I am using a lathe, and this not only simplifies it, it allows you to make the whole thing fancy, as you'll see, but it is not necessary to use a lathe. If I were to do it without one, I'd simply cut it with a hack saw as accurately as possible, then clean the ends up with some wet/dry paper on a flat surface. However you do it, measure the length, and make it an even millimeter number. In this case, I made it 65.00 mm long.

 

The ram: I started with a piece of 1.250" OD stock. Aluminum bar is usually slightly oversized. I turned it down (it didn't take much) so it was a nice sliding fit into the tube. Without a lathe, I'd figure out a way to possibly mount it in a drill press, or some other motorized device, and reduce the dimension with wet/dry paper backed by a file or flat. Even better, find a ram that is already a nice fit!

 

Using the lathe, I scored rings every 5mm. This can be done without one by carefully marking the ram, and you can engrave a mark every 5mm, or even easier, give it a little center pop - just mark it permanently so you can determine how far it has gone into the tube.

 

http://www.5bears.com/firew/ram01.jpg

 

I jazzed mine up a bit by turning the handle and giving the end a coin knurl:

 

http://www.5bears.com/firew/ram06.jpg

 

It is best to polish as much as possible, those portions of the ram and tube that are in contact with moist materials. A high polish really helps prevent comps from sticking to the metal. I used steel wool and some simichrome polish on the walls of the tube, and the ram end.

 

To use the system, weigh out the material you want to ram, accounting for moisture if wet, and pack it into the tube end, with the ram partially entered:

 

http://www.5bears.com/firew/ram08.jpg

http://www.5bears.com/firew/ram09.jpg

 

Then, simply place the open end on a metal flat strong enough to withstand the force of the press. You can use a hydraulic press like this one...

 

http://www.5bears.com/firew/ram10.jpg

 

Or, you can simply use a mallet, a big vise, anything that will apply pressure. The volume is determined by noting how many of your tick marks have entered the tube. With the tube length being known, it is then easy to determine the volume being compacted. Works well, although this comp is messy, and too moist:

 

http://www.5bears.com/firew/ram12.jpg

 

The disk is easily exposed by holding the tube, and with a twisting motion, force the ram to expel the disk. While being pressed, there is no need to support the tube other than to be sure it is in contact with the base plate. The forces are outwards, and there is no tendency for the tube to climb. A piece of plastic covering the base helps keep the disk from sticking to the base plate.

 

If I really wanted it to last, I'd make it out of brass, bronze, or stainless steel, but aluminum is fine when we are talking about home shop pressures. I've tried this ram with BP and it works perfectly.

 

I know this is nothing new, but I wanted to contribute something to the group! Heavy-walled tube is cheap and common, and really all you need to do is find a ram that will fit, mark it out, and start pressing!

[TheSidewinder]

Interesting and well-made tutorial.

 

What would be the byproducts of that mix, if used it as a propellant like you outline?

 

I suspect a muzzleloader would scream in protest if you used it, although a thorough cleaning within a few hours would (most likely) prevent any damage.

[pudidotdk]

Nice job on the lathe, mate!

I seriously have to get back into learning to use the lathe, so far I have only made small bits, and it takes forever (and sometimes turns out ugly, not shiny like yours)... ugh!

[Pretty green flame]

The humble lathe, a really usefull tool to have around the workshop, the best 500€ I spent.

 

Good work on the pump there Swede. I personally find the markings confusing as I never know how many marks are in the tube. Usually I just mark a certain spot as a gauge so all pumped stars can be cut to the same lenght. Your pump is really fancy, mine are more stone age but made of aluminium and brass

[Swede]

A lathe is definitely an incredibly handy tool. A simple 8" swing lathe will make all sorts of wonderful tools like rocket tooling, pumps, pins for star plates, rams, etc. The money you save being able to make your own stuff will pay for the machine, and the best part, you make exactly what you need rather than having to settle for less.

 

TS, my understanding of the byproducts of KNO3:Sucrose is this:

9.6KNO3+C12H22O11--->4.8K2CO3+7.2CO2+11H2O+4.8N2

 

So you get quite a bit of gas, CO2 and nitrogen, water vapor, and potassium salts. The rocket people usually melt and cast the stuff. I am trying to granulate it, and it's been a bitch. The idea is to come up with a method to make a true emergency propellant even simpler than BP. You can stuff any cartridge case (that normally takes smokeless) full of BP, and it should be safe, and from what I've seen, KNO3:sucrose, granulated, is even less energetic. It makes a mess in the bore much like BP though, and will require similar cleaning.

 

I've got a chronograph, and am building a .50" smoothbore test rig with both a piston and a strain gauge setup to measure comparative chamber pressures. The piston will crush solder wire, and by measuring the amount of crush, I can compare this stuff to other powders like BP and 777.

 

Anyway, thanks for the kind comments. It doesn't have to be nearly so fancy, but I enjoy lathe work, and by buying or scrounging both aluminum tube, and bar stock, it's not too tough to make several different rams/pumps of differing diameters and legths.