Experience with extruded nitro powder

[Henry VIII]

Greetings. Recently acquired a lot of loaded large bore nitro cartridges. As components are very difficult to obtain here, I am considering breaking them down for components. The extruded nitro powder should not be damaged as these are generally straight case cartridges.

Do any members have experience with this powder ? Thank you.

[lylejb]

The problem is powder varies greatly in burn rate. As you did not load these cartridges, you have no idea what powder or powders they are loaded with. If these are factory loaded rounds, factories often obtain powders that are not the same as commercial reloading powder. In short, without knowing where you're starting from, it's very difficult to know how to get where you want to go.

[Henry VIII]

That is a valid concern. I believe having a full profile of the cartridge performance, the performance of the powder could be determined. If the nitro powder produces velocity X with bullet Y at a pressure of Z, searching loading data should reveal a like combination from available powders.

[Ballistics in Scotland]

Not necessarily. Bullets accelerate in proportion to the pressure on them. Velocity tells you what the average pressure has been. But it could be moderately high pressure near the chamber and low pressure further down the bore, or it could be dangerously high declining to very low.

The first thing is, it would be very useful to know how those cartridges have been performing in the rifle for which they were intended. I would prefer to see the fired cases and their primers if they are factory cartridges, and I would very much more greatly wish to see them if they were someone's handloads.

If all that checks out, I think the powder would be safely usable in cartridges of similar shape and proportions - notably in capacity, bore diameter and bullet weight. Differing much from those may produce different behaviour.

[Henry VIII]

Extruded nitro powder is very regular in its performance. These are all British made factory loads. They were designed to have low pressures and good performance in all sorts of conditions. The only concern with these powders is in bottle neck cartridges subjected to harsh handling. That can cause the powder compressed in the neck by case forming (done after the powder is in case) to break off from the powder in the case. This can cause irregular ignition, hangfires and spikes in pressure. While nitro is somewhat erosive, better to have it than no powder at all.

[NuJudge]

Ammunition factories buy bulk powders which, even for the same designated powder, vary quite a bit in powder burn rate, lot-to-lot. If I knew that a batch of cartridges of one caliber came from the same production lot, I might think it safe to pull bullets and re-use the powder.

A lot of British-made ammo used Cordite into the 1950's, from what I have read, the Cordite rods running the length of the case. I have broken down a few .303 cartridges to look at the Cordite. It was always long rods, although I have read that the Cordite loaded in revolver cartridges was chopped up into short lengths.

[swheeler]

You must be talking about Cordite?

[Henry VIII]

Yes that's what it is.

[wmitty]

This is interesting; as a shooter in the U.S. I've only heard about Cordite and its use as a propellant in the U.K. How is the burning rate regulated? It would seem the undamaged strands could be used to load other rounds if, as you say, it is quite consistent in performance.

[Henry VIII]

The burning rates are controlled by the powder compound and the diameter of the strands. The cartridge the powder is salvaged from will instruct as to the canister equivalent. As with canister powders, the large bore heavy bullet cartridges use cordite powders with medium burn rates which should match up well with 30-40 caliber lead bullet loads.

[Wayne Smith]

Extruded strands or extruded cut strands? The extruded strands were loaded into the .303 cartridges before they were necked. Reloading such would be a headache. If you are cutting the strands to load them you are changing the burning speed dramatically.

[NoAngel]

No way I would fool with that mess. You are free to do as you like and I won't tell you what to do but no way for me.

Incidentally, my avatar was obtained from setting fire to a large pile of cordite after pulling down a bunch of 303 british ammo for the bullets. I thought it looked like a fire demon. Certainly some cool effects.


http://i1216.photobucket.com/albums/dd371/Reloadingfool/IMG_0999_zpsuxwwet3u.jpg

[Ballistics in Scotland]

Extruded strands or extruded cut strands? The extruded strands were loaded into the .303 cartridges before they were necked. Reloading such would be a headache. If you are cutting the strandss to load them you are changing the burning speed dramatically.

You are also making the powder more regressive, i.e. declining more in gas supply as it burns. For one strand's worth of cordite will burn itself away on a lot of ends rather than just two, and the grains will disappear while there would be a long, very thin strand left.

Add to that the fact that while the burning rate of black powder is approximately proportional to the pressure on it, the burning rate of smokeless increases much more than in proportion. Or in plain increase, anything that tends to run up the pressure a bit with smokeless, will run it up quite a lot. Yes, it could be dramatic.

Cutting into grains will increase the peak pressure near the chamber, and reduce it near the muzzle. But whoever heard of a rifle taking any harm from thinness near the muzzle, unless there was an obstruction? It is peak pressure that causes blow-ups.

That isn't to say that cordite was never cut into grains. Chopped thinner strands were used in the .455 revolver. Riflite was a chopped cordite used in the .303, starting in the days when cordite had a 58% nitroglycerin content, and possibly after its reduction. It was used with a slightly smaller charge than cordite. Axite, a rather more popular sporting powder, was pretty much like cordite in grains with a higher petroleum jelly content. Originally intended to reduce nickel fouling, it was found that although petroleum jelly reduced the energy content, the deposited lubricant would increase the velocity even of ordinary cordite fired after Axite. Like many another bright idea in firearms technology, there must be some good reason why we aren't all doing it.

[samari46]

May be a little off topic so here goes. Think the history channel did a story about Gallipoli and in the story they had sent scuba divers down to see what was down in the ocean. Short story was that the divers came up with cordite that had come from naval guns, looked almost like huge spagetti strands. One was actually lit with a match and after all those decades under water it still burned. Frank