correct amount of primer and powder

[bobo]

In order to improvise ammo from scratch, the obviously best choice is to use blanks for the primer. However, making lead styphnate or azide or mercury fulminate holds no real challenge, thus starting without blanks should be possible. The question that I do not find answered, is how much primer to use. Is this a critical thing or do we just pour in some primer, pressurize it and see if it explodes nicely? I suppose, if I test it dry and the case does not break then the amount is all right, is this OK?

[Charles Owlen Picket]

This is a VERY complex query. The concept is to utilize the nitric esters as propellants NOT as explosives. The use of primers (in context) is to induce flame - NOT induce detonation. That is why certain materials are used; ones that produce flame spit not detonation wave.

Ratio & proportioning is inter-related to this concept. Read the patents on firearms primers and you will notice a pattern of innovation in the primer. The issues are IMPACT initiation & resultant flame. NOT detonation wave. The anvil (Boxer) in the primer or casing (in a Berdan unit) is designed to accomplish more than just impact initiation but to channel the flame to the propellant.

The unspoken issue is that NG & NC is an explosive but may be induced to propel a bullet*. The dependent factor is the type of initiation and the ratio of materials in the space provided. Too little "propellant" in too large a space may induce an explosion. What is sought is to BURN the material to provide gases.

Many of the older patent provide clues to this end. There are few hard & fast rules as cartridges & chambers vary. Begin with a book on re-loading and understand the concept from a (home) factory standpoint. Find out what NOT to do. Then extrapolate what is needed. It is best to begin with too little primer so as to insure a BURNING process.

Interdependent factors include; chamber size, bullet weight/design, powder composition/design, barrel length/diameter, & rifling. There is a problematic situation that is called "detonation" in hand-loading circles. This is when too little powder exists in a casing and there is a resulting catastrophic explosion. Research this phenomenon & you will have a lot of material to base further extrapolations on. This is an involved science & there is no pat, easy answer to this query.

As a very gross generality; it's better to use too little primer than too much. Do not use primary materials that result in sharp detonation waves. That is why lead styphnate and tetrazene are often mainstays of the materials used. Powdered glass is added to increase both impact sensitivity and to moderate hot spot detonation plume.

* When canister powders are sold in the EU they are marked as explosives. When sold in the USA they are not. This is an issue of politics. Reading materials from certain factories one can see how the issues are skirted due to the inference that only firearms primers will be used to initiate. Source sited is REX shotgun powder, made in Hungary & associated written material & packaging (2005).
But in fact if a detonation wave material was involved, the canister powders will detonate very, very well.

[tomu]

Be careful if you use the NC-powder from blanks. It's really fast in fact it is faster burning thn any powder used in reloading.

A far better choice would be the powder used in cartouches for bolt fastening guns like HILTI or similar.

Well you can not overload a primer, there is not much volume in the primer case. Just experiment. But if you use blanks as a powder source you got the primers already, don't you?

[bobo]

The point of this question is not: "i want to play with ammo and want the quickest way to get it", rather, "I want to be able to source all components from scratch and do it right". It is best if I can relate any home made chemical to more common products. Given the fact that all parts are available without too much trouble, it is my intention to experiment with commercial powder, homemade powder and powder from the blanks to compare, as well as figure out how to do the caps from scratch.

I have confidence in my abilities and equipment in the chemistry department, and produce clean powder and primary. The engineering department is a different story, hence this question.

As for the primers. I have read that mercury fulminate primers used to be mixed with chlorates. I am also aware that there is an empty space between propellant and primary to facilitate flaming. Probably this will also function to make sure the unavoidable detonation wave does not hit the propellant. It is as if a shock sensitive flash powder would do the job as well...

As for the propellant. You mention the nitroglycerin powder. Is this good for small arms ammo? I was led to believe that the common types of smokeless powder are NC with some additive in the % range, or single-base. In something goes wrong with the loading then I do not want to hold a cartridge that detonates its propellant instead of just burns it.

Given the complexity of this matter, does this mean I should at least start out with a commercial reloading set and substitute with home-made stuff only after mastering the process?

[Charles Owlen Picket]

Given the complexity of this matter, does this mean I should at least start out with a commercial reloading set and substitute with home-made stuff only after mastering the process?
Unquestionably, yes.

NG exists within the double-based smokeless powder (DBSP) but not as a separate dry powder; - as an absorbed material with the polymer matrix of the powder granules (a misnomer, as they are often extruded, etc - a whole other subject).

Realistically the more you read about hand loading the closer you'll get to what you want to achieve. And frankly don't get a majority of information from internet sources: some of the most boneheaded slathering shovelfuls of bullshit I have ever read have existed from the local "retired Navy SEAL TEAM Six guys".
Generalist perspectives should mostly steer you to further reading and have sources sited. Hand loading is an area where you are really working with professional level nitric esters & the resultant pitfalls......Good luck & use caution.

[tomu]

Making your own NC-Powder is a real challenge and you can't use any data from reloading charts because the characteristics of your homebrew powder would be different from any of the manufacturers.

Many NC-Powders are double-based powders especially the powders used for handguns. They contain different percentages of Nitroglycerin, as well as phlegmatizers, stabilizers and burn inhibitors and have a certain geometric to achieve the desired burn rate and pressure curve. Have fun!

You have to test the performance and characteristics of your powder by yourself. I wouldn't use a gun for this but would make my own test device from very strong and tough chrome-molybdenum or chrome-nickel steel with a wall thickness of several centimeters at the breech.

Btw. you don't want the steel to be hard, chambers and barrels usually have a hardness of around HRC 30 or even below, you don't want to be showered with shrapnell if anything goes terribly wrong. .

Be especially careful with high pressure cartridges like 9 mm Luger, .357 Magnum, .44 Magnum etc. or any rifle ammo.

Learn to read the signs the brass shells show after firing, look for signs of excessive pressure. Like flattend firing pin intentations, cratering around the firing pin intentation, enlarged primer pockets, bulged or split brass shells etc.

[Cobalt.45]

Given the complexity of this matter, does this mean I should at least start out with a commercial reloading set and substitute with home-made stuff only after mastering the process?

As an aside here, handloading need not be a overly expensive undertaking, equipment-wise. Lee markets a very inexpensive cartridge reloading tool called (appropriately enough) the Lee Loader. Sells for around $30 and has what is needed to reload a cartridge.

See: http://www.leeprecision.com/cgi/catalog/browse.cgi?1215902626.4071=/html/catalog/cleeloader.html

A down side to this tool is that it's slow. And resizing straight-walled shells will get old pretty quick because of the force required and lack of leverage the tool affords.

Primers can cause a fairly wide variation in pressures generated in reloaded shells, given their small overall charge contribution. If you were on the edge, pressure-wise, a change in primers could help (or hurt) the situation.

[lucas]

I would recommend starting with about 5mg of primer composition for small primers and 10mg for large primers. I'd suggest a simple binder like shellac or red-gum would be ideal. Nitrocellulose lacquer would be worth considering maybe, but I'd try to keep the binder to a minimum. The use of "old fashioned mixtures" is probably worth investigating. Mercury fulminate with 20% chlorate is a good mixture if a little toxic and corrosive. Proper cleaning and ventilation during use should be standard practice anyway. Initiation should be always done with the lowest power primer that is reliable. That applies to reloading with commercial components and should be applied to re-manufactured primers and custom primers.

[drsx]

The question that I do not find answered, is how much primer to use.
I would recommend starting with about 5mg of primer composition for small primers and 10mg for large primers.

Once I was the opportunity to weigh a primer before and after firing. The primer was Cheddite Clerinox .209 shotshell primer. The primer fired from an otherwise empty, open shotgun shell (uncrimped shell without powder, without shot and without wads). Weight of primer before firing: 0.80 gram, weight of primer after firing: 0.75 gram, the scale I used was a cheap digital scale with 0.01 gram accuracy.

[Wallybanger]

You would be surprised how much your primer can change your chamber pressures. A hot primer can easily take a mid range load to dangerously high pressures. KABOOMS generally aren't a lot of fun and there are lots of videos on the net of people's faces being shredded.

First of all, I would recommend picking up a reloading manual and learning about different loads, cartridges and ballistics.

Secondly, I would recommend NOT reinventing the wheel and to try to replicate an existing, low pressure cartridge. .45ACP might be a good starting point.

finally, I would say that the amount of primer compound wouldn't be as important as the consistency from primer to primer. If you have one primer/cartridge and it blows up, no problem (assuming you're not holding the firearm). If you have multiple primers that are inconsistent, you may get false sense of security from early success and then proceed to blow your face off.

Be careful. Don't underestimate the amount of pressure inside the chamber of a gun.

Are you wanting this for a SHTF scenario? Hunting? Self defense? You may want SP for fighting but good old BP would be fine for hunting and casual self defense. Does it have to be a cartridge? How about looking into a percussion cap musket using BP? You could cast your own lead balls and everything.
TThere is a problematic situation that is called "detonation" in hand-loading circles. This is when too little powder exists in a casing and there is a resulting catastrophic explosion.
I know this as "Flash Over". When there isn't enough powder in the case, the surface area of the powder is greatly increased so in stead of a gradual increase in pressure as the powder burns for end to end, you get all of the powder being ignited at once which is not good.
As an aside here, handloading need not be a overly expensive undertaking, equipment-wise. Lee markets a very inexpensive cartridge reloading tool called (appropriately enough) the Lee Loader. Sells for around $30 and has what is needed to reload a cartridge.
That's an expensive lee loader. Should be able to get one for $10-$15. They work extremely well for cartridges that don't require full length resizing. I can reload 20rnds in about 15mins. (I prefer the lee loader over my reloading press for .303Brit as I can get much better accuracy)