Low Velocity Exploding Target Composition

[Wiley]

I've heard a few theories about what .22 sensitive exploding targets, such as the ones from In The Red, are made of. Some say they're regular perc/Al flash.

 

I've always liked the idea of Gabe Mortes, those 10 pound suspended sacks of flash that the Italians used to use to end a show with a riduculusly loud report. I know that this type of device can be made much smaller, and thus more suitable for a smaller show. If these targets from In the Red are really just a bag of perc/Al, they should be fuse sensitive and thus could be used as miniature Gabe Mortes. The price is pretty steep (~$20 a pound) but if the effect is decent it could be worth the cost. That price is comparable to Pyrodex, which I use in my salute cannons. 4 ounces is very loud, and can easily be felt from about 120-150 feet away. Here's a video of three of them in a row. https://m.youtube.com/watch?v=hqS5Maxijpg

 

It would be interesting to see how a full pound of exploding target goodness compares to a quarter pound of black powder substitute.

[Mumbles]

There are two extremes out there. There is Tannerite, which generally requires a higher velocity round. These are AN/Al, plus some additives. Then there are the one that are sensitive to pellet rifles. You can get some of the details in patent US 2010/0275802. For a low velocity, real bullet, the composition is probably somewhere in the middle. Perhaps something like 70/30 with some Ti and/or antimony trisulfide to increase the sensitivity and effect.

[Sparx88]

http://www.freepatentsonline.com/y2010/0275802.html

 

looks like the thiourea in a regent grade would be a start. ebay has a lot.

 

1 lb of standard tannerite shot with a 270 was more than enough to scare everyone around me. I did it once just to see how it works a few years ago and have'nt since. I tried making some to work with a .22 but gave up on it. I would still like to know a cheaper working recipe myself for the pellet/.22

 

Lack of funds, plus I came up with a noise maker "flash pot" thats pretty good in terms of cost, volume adjustment, and safety. For me, this is what I use now; 3" tall, 2 7/8" wide, 1 " bore. I wrap 7 grams 70/30 in 1 layer of tissue paper or cheap toilet paper with a short peice of masking tape and some visco and push it to the bottom. No wadding, no ramming just set it down in there and light it. It's made from 1018 bar stock.

Edited October 5, 2014 by Sparx88

[Wiley]

That's an interesting device, Sparx. Bet it makes a nice little bang. However, the effect I'm going for has to be of a bit bigger magnitude to compete with the 2" salute cannons. I.e. high volume is important, but the concussion is even more important. I've never er witnessed a ground salute bigger than 50g go off in person, and I've never seen exploding targets of any type in action. I could always find a more massive piece of steel and make a cannon that takes half a pound of Pyrodex, but I thought that since such a cannon could only be used a couple of times out of the year, a Gabe Morte type device could supply a similar punch at the cost of higher price per boom.

 

Here are some videos of the targets I'm referencing. It makes me wonder how loud they really are, seeing how close the shooter is in some of them.

https://m.youtube.com/watch?v=kfGU1PKmuFY

 

https://m.youtube.com/watch?v=KcS5x4PTUy4

 

https://m.youtube.com/watch?v=kGrGJReKcS4

[FlaMtnBkr]

Just to verify, you aren't trying to put this in your salute cannon? I don't think so but want to make sure you never do this.

 

Do you use wading with your pyrodex? I bet regular black powder would be louder. I believe pyrodex needs high pressure to equal BP and you probably won't get there without a projectile.

 

Is there any reason you don't just buy flash components instead of buying exploding targets? What size target are you thinking of for your noise making? Do you like shooting? Why not combine shooting with noise making? They are fun to shoot and if you have the space to make that kind of noise then you should have enough to shoot.

 

It isn't hard to make a pellet rifle sensitive exploding target. But by their nature they have to be sensitive and you have to mix together things we are told not to mix because we don't want sensitivity.

 

If you want the most noise from the least amount of composition, you want to step up to AN based exploding targets. They are louder, more boom-y, and their sound travels further, at least in my experiences. If you have to light your noise maker with a fuse I can tell you how. But let's go to the HE forum or PM me for those details.

[Sparx88]

Looking into these further I'm at the conclusion that this may be the most important development of a pyrotechnic composition/device in quite awile. People for years and years have been in search of a better, safer, legal for everyone in the 50 states, and can be mailed with no license of any kind required, way to create this effect.

 

I know I'm not the first to say that and won't be the last. True, some believe this sort of effect is mostly for "thump junkies" or sub par ameteurs who don't know how to build a decent shell or rocket etc etc. Thats just disrespectful. Like a football fan saying ping pong fans are monkeys.

 

Do what you enjoy and enjoy what you do and I assure everyone that once my first order arrives I will enjoy it to the fullest and I'll post videos, as I'm a video junky.

Edited October 9, 2014 by Sparx88

[Wiley]

I've found some videos on Youtube showing an oxidizer that is clearly powdered, and a fuel that is very dark/black. I speculate that it could be Indian blackhead, maybe with some antimony trisulfide in there to sensitize things a bit. If I do happen to order some of these targets, I'll see what the mix does in a bag when initiated with a fuse. It sure pops when hit by a bullet, so if the ingredients are what I think they are, it should be nice and loud when lit via fuse. I'm not sure what size to order yet, as they come in 3oz, 8oz, and 1lb quantities, but I'm thinking that it would be best to start out with the smallest (and cheapest) size first.

[Sparx88]

Looking through the patent information it appears that p.chlorate, charcoal, and thiourea are used and that makes it legal to make, own, use and send through the mail in all 50 states. The oxidizer has to be in a seperate bag, container etc from the others but all 3 can be in the same box.

[Jakenbake]

That could make some nasty stuff. According to the Wiki on Thiourea "The material has the unusual property of changing to ammonium thiocyanate upon heating above 130 °C." Ammonium Chlorate with Sulfur anyone?

[Wiley]

Interesting. It'll be interesting to see what it does when lit with a fuse. I'm thinking that worst case, it'll need to be confined in something like Sparx's flash pot or a cardboard tube.

[Seymour]

I found 70/30 KP/Dark Al to be sensitive enough for even .77 cheap air rifles to set off with decent reliability (better than my reliability at hitting them, at least!)

 

I've tried adding coarse metals, and sulfur to sensitize them, but it never helped much. I'd say chlorate is probably better for the low cost rather than the sensitivity being required. If you are going to use up a few hundred grams of chemicals just for a target, the costs could stack up. However to those who want to shoot at things that explode, but feel wary of using excessively sensitive and or exotic mixes, you don't have to.

Edited October 9, 2014 by Seymour

[FlaMtnBkr]

I tried KP and dark Al and they were not reliable at all when shot with a .177 pellet and contained in a cup set. It took something a bit more sensitive to explode with a pellet. In fact I don't think that was a 100% reliable when shot with a .22 rifle.

 

Fyi I was using a RWS/Diana model 48 side cocker that I believe is supposed to be an 1100 ft/s rifle.

[Bobosan]

Fyi I was using a RWS/Diana model 48 side cocker that I believe is supposed to be an 1100 ft/s rifle.

 

Nice rifle. I have that same RWS model with a red dot scope.

[mabuse00]

How about placing some red phosphorus in/on the bullet?

It will have some effect on the projectiles behaviour, but maybe this can be solved somehow.

 

A tiny hole in drilled in the front of the bullet filled with that stuff should dramatically increase the sensibility of any flash type composition when it hits.

Edited October 9, 2014 by mabuse00

[wildcherryxoxo]

Sounds like a terrible waste of red phosphorus

[Seymour]

Admittedly I was shooting at flash which was placed against a solid wooden 'backing'. I'm sure that helped a lot.

[Jakenbake]

Red P on the tip of the bullet?? Really? I hope we don't need to discuss the reasons why that would be a bad idea. All you need to do is use the right mix of chems and it will be 100% reliable with a 22.

 

I believe it was WSM who first posted the formula

4-perc

1-antimony trisulfide

1-dark al

[Wiley]

That's about what I guessed the In The Red low velocity targets are made of. There are videos of them that do show a fairly substantial white flash.

[taiwanluthiers]

might be better to tape a tiny amount of red P on the target itself, separated by a piece of plastic. The impact will mix the two.

[Sparx88]

------In case anyone missed earlier replies in this thread here's the scoop from the patent.-------

 

 

 

 

BAKER & DANIELS LLP (300 NORTH MERIDIAN STREET, SUITE 2700, INDIANAPOLIS, IN, 46204, US)

Claims:

1. An impact initiated pyrotechnic target including an impact initiated pyrotechnic composition which can be initiated by the impact of an inert projectile, the pyrotechnic composition including: an oxidising agent; optionally, a fuel or reducing agent; a sensitiser in the form of a sulfur containing compound; and optionally, a binder.

2. An impact initiated pyrotechnic target according to claim 1 in which the sensitiser is thiourea.

3. An impact initiated pyrotechnic target according to claim 1 in which the oxidising agent is a chlorate.

4. An impact initiated pyrotechnic target according to claim 3 in which the oxidising agent is potassium chlorate.

5. An impact initiated pyrotechnic target according to claim 1 in which the fuel or reducing agent is charcoal.

6. An impact initiated pyrotechnic target according to claim 1 in which impact initiated pyrotechnic composition includes, by weight, 30-70% of the oxidising agent, 0-60% of the fuel or reducing agent, 8-40% of the sensitiser, and 0-15% of the binder.

7. An impact initiated pyrotechnic target according to claim 1 in which the binder is a resin.

8. An impact initiated pyrotechnic target according to claim 1, further comprising a secondary pyrotechnic composition which is formulated to be initiated by the impact initiated pyrotechnic composition to produce a desired signalling effect.

9. An impact initiated pyrotechnic target according to claim 8 in which the secondary pyrotechnic composition includes metal particles and an oxidising agent.

10. An impact initiated pyrotechnic target according to claim 8 in which the secondary pyrotechnic composition is blended with the impact initiated pyrotechnic composition.

11. An impact initiated pyrotechnic target according to claim 1 in which the impact initiated pyrotechnic composition is disposed in front of a resilient surface, the resilient surface being sufficiently resilient to resist the impact of the projectile to an extent which allows initiation of the impact initiated pyrotechnic composition to take place.

12. An impact initiated pyrotechnic target including: a housing, the housing comprising a resilient surface acting as a backing plate of the housing, wherein the backing plate includes a wall upstanding therefrom forming an enclosure; and an impact initiated pyrotechnic composition disposed in the enclosure, the impact initiated pyrotechnic composition comprising: an oxidising agent optionally, a fuel or reducing agent; a sensitiser in the form of a sulfur containing compound; and optionally, a binder.

13. An impact initiated pyrotechnic target according to claim 12 in which the housing further includes a lid which is disposed over the wall so that the housing fully encloses the impact initiated pyrotechnic composition.

14. A solid impact initiated pyrotechnic composition including: an oxidising agent; optionally, a fuel or reducing agent; a sensitiser in the form of a sulfur containing compound; and optionally, a binder, wherein the solid impact initiated pyrotechnic composition signals a strike by an impacting projectile.

15. (canceled)

16. (canceled)

17. (canceled)

18. An impact initiated pyrotechnic target according to claim 14, wherein the impacting projectile is inert.

19. An impact initiated pyrotechnic target according to claim 8, in which the impact initiated pyrotechnic composition is disposed in front of a resilient surface, the resilient surface being sufficiently resilient to resist the impact of the projectile to an extent which allows initiation of the impact initiated pyrotechnic composition to take place.

20. An impact initiated pyrotechnic target according to claim 8 in which the sensitiser is thiourea.

21. An impact initiated pyrotechnic target according to claim 8 in which the oxidising agent is a chlorate.

22. An impact initiated pyrotechnic target according to claim 8 in which the fuel or reducing agent is charcoal.

23. An impact initiated pyrotechnic target according to claim 1 in which the binder is an acaroid resin.

Description:

This invention relates to impact initiated pyrotechnic targets and impact initiated pyrotechnic compositions.

It is known to provide practice targets for various shooting purposes. For example, targets may be used in conjunction with firearms such as rifles and pistols, and air propelled arms such as air rifles and air pistols. The target may be of the type which is intended to be held in a fixed position, and which may have indicia located thereon such as a number of concentric rings defining a “bullseye”. Alternatively, the target may be intended to be used as a moving target such as a “clay pigeon”. It is known from U.S. Pat. No. 4,498,677 and WO02/35175 to provide an explosive target which registers a hit by providing an explosive event. However, it has proven difficult to produce a pyrotechnic which can be satisfactorily ignited by the impact of a relatively low energy projectile such as a pellet or slug discharged by a pneumatic weapon such as an air rifle. Additionally, whilst there is a need to provide a target which is sufficiently sensitive to provide a reaction to a hit by a relatively low energy projectile such as an air gun pellet, the active pyrotechnic used in the target should not be so sensitive as to present a hazard during manufacture, handling or storage. A related and important consideration is that the nature of the active pyrotechnic should not render its preparation illegal under national laws. The laws of the UK are particularly restrictive in terms of the nature of the pyrotechnic and its manufacture. For example, the explosive formulation described in U.S. Pat. No. 4,498,677 would not be legal under UK law.

The present invention, in at least some of its embodiments, addresses the above described problems and needs.

According to a first aspect of the invention there is provided an impact initiated pyrotechnic target including an impact initiated pyrotechnic composition which can be initiated by the impact of an inert projectile, said pyrotechnic composition including:

an oxidising agent;

optionally, a fuel or reducing agent;

a sensitiser in the form of a sulfur containing compound; and

optionally, a binder.

The sensitiser acts as a source of bound sulfur. This is advantageous, because the sulfur provides an initiation enhancing sensitisation. However, the pyrotechnic composition is safer than compositions which utilise elemental sulfur by virtue of being chemically bonded to other atomic constituents of the sensitiser. In this way, the stringent UK legislation governing pyrotechnics can be satisfied.

Very preferably, the sensitiser is thiourea. Surprisingly, it has been found that the presence of thiourea can act as a highly advantageous sensitiser, enabling the provision of a pyrotechnic composition which is sufficiently sensitive to provide enhanced impact initiation. A further advantage is that the thiourea can provide an accelerated burn rate. In at least some embodiments, the use of thiourea can permit impact initiation by a relatively low energy projectile such as an air rifle or air pistol pellet.

For the avoidance of doubt, the term “inert” as used herein refers to a projectile which ignites the target by virtue of its kinetic energy on impact, i.e., a projectile which is non-explosive and does not react chemically with the pyrotechnic composition.

Preferably, the oxidising agent is a chlorate, most preferably potassium chlorate.

Advantageously, a fuel or reducing agent is present. Preferably the fuel or reducing agent is charcoal. Other fuels or reducing agents, such as organic fuels, for example shellac, might be utilised. However, charcoal can provide excellent results and has the advantage that its use in the manufacture of pyrotechnics in the UK is legal.

Preferred embodiments utilise a chlorate in combination with charcoal and thiourea. A particular preferred combination is potassium chlorate, charcoal and thiourea. It should be noted that the present inventors have found that mixtures of potassium chlorate and charcoal without thiourea were not sensitive enough for use with relatively low energy projectiles such as air gun pellets at practical firing ranges. It is estimated that the presence of thiourea reduces the ignition temperature of the potassium chlorate/charcoal pyrotechnic composition by about 200° C., thereby providing greatly enhanced sensitivity to impact initiation.

Whilst it is preferred that a fuel or reducing agent is present in addition to the thiourea, it may be possible to provide an impact initiated pyrotechnic composition which does not include a fuel or reducing agent. Tests have revealed that combinations of potassium chlorate and thiourea (which acts as a fuel and a sensitiser) can be caused to react explosively at temperatures as low as 155° C.

Preferably, the impact initiated pyrotechnic composition includes, by weight, 30-70% of the oxidising agent, 0-60% of the fuel or reducing agent, 8-40% sensitiser and 0-15% of the binder, with the proviso that the total weight percentages of these components do not exceed 100%.

Preferably, the impact initiated pyrotechnic composition includes 40-60% by weight of the oxidising agent.

Preferably, the impact initiated pyrotechnic composition includes 20-40% by weight of the fuel or reducing agent.

Preferably, the impact initiated pyrotechnic composition includes 10-40% by weight of thiourea, more preferably 12-30% by weight of sensitiser.

Preferably, the impact initiated pyrotechnic composition includes 1-10% by weight of the binder.

The binder is preferably a resin, such as acaroid resin or shellac. Other suitable binders may be used. In general, the binder is a polymeric matrix of some sort.

The target may further comprise a secondary pyrotechnic composition which is formulated to be initiated by the impact initiated pyrotechnic composition to produce a desired signalling effect. The desired signalling effect may be one or more of an enhanced explosion, a desired flame colour, enhanced smoke production, a desired noise level on initiation, a desired burn rate and an incandescent display.

The secondary, pyrotechnic composition can be selected from a wide range of suitable candidates in order to provide the desired signalling effect. In preferred embodiments, the secondary pyrotechnic composition includes metal particles and an oxidizing agent. The metal particles may be aluminium, magnesium or a combination of both.

The secondary pyrotechnic composition may include a suitable binder.

In general, the secondary pyrotechnic composition will include an oxidising agent which is somewhat more stable than the oxidising agent used in the impact initiated pyrotechnic composition. Perchlorates may be used.

Typically, the impact initiated pyrotechnic composition and the secondary pyrotechnic composition are blended together. The blend ratio may be in the range 1.5:1 to 4:1 by weight of impact initiated pyrotechnic composition to secondary pyrotechnic composition. In general, the impact initiated pyrotechnic composition and the secondary pyrotechnic composition are granular, and the grains are blended together.

The impact initiated pyrotechnic composition may be disposed in front of a resilient surface, the resilient surface being sufficiently resilient to resist the impact of the projectile to an extent which allows initiation of the impact initiated pyrotechnic composition to take place.

Without wishing to be bound by any particular theory, it is believed that the resilience of the surface permits a compression of the pyrotechnic composition to occur upon impact which causes an increase in temperature which in turn causes the pyrotechnic composition to ignite. Depending on the impact initiating pyrotechnic composition and the envisaged implication, it may not be necessary to utilise a resilient surface in order to obtain impact initiation. The target may include a housing, in which the resilient surface acts as a backing plate of the housing, the backing plate having a wall upstanding therefrom forming an enclosure in which the impact initiating pyrotechnic composition is disposed. Typically the backing plate and wall are formed from a metal, such as aluminium. The housing may further include a lid which is disposed over the wall so that the housing fully encloses the impact initiating pyrotechnic composition. The lid may be formed from sheet material such as card or paper.

The compositions may be in granular form, in which instance a milling technique may be used to produce the granules. Alternatively, the compositions may be produced using a slurry of the constituents which is subsequently dried.

The targets of the invention may be used as targets for firearms, air-operated arms such as air rifles and air pistols, or even in archery. The targets may be intended for use as essentially a static target, in which instance the targets may consist essentially of the housing described above. Alternatively, the targets may be a moving target such as a clay pigeon.

According to a second aspect of the invention there is provided a solid impact initiated pyrotechnic composition including:

an oxidising agent;

optionally, a fuel or reducing agent;

a sensitiser in the form of a sulfur containing compound; and

optionally, a binder.

According to a third aspect of the invention there is provided the use of a solid impact initiated pyrotechnic composition of the second aspect of the invention as an impact initiated pyrotechnic.

According to a fourth aspect of the invention there is provided the use of a solid impact initiated pyrotechnic composition according to the second aspect of the invention in an impact initiated pyrotechnic target for signalling a strike by an impacting inert projectile.

Whilst the invention has been described above, it extends to any inventive combination or sub-combination of the features set out above or in the following description or drawings or claims.

Embodiments of targets and compositions in accordance with the invention will now be described with reference to the accompany drawing which shows

(a) an exploded view

( a perspective view

© a cross-sectional view of a target of the invention.

FIG. 1 depicts as housing of the invention, shown generally at 10, which comprises a casing 12, an explosive powder 14, and a lid 16. The casing 12 comprises a circular backing plate 12a and a peripheral circular wall 12b upstanding therefrom. The casing 12 is formed from a suitable metal, such as aluminium or steel. The casing 12 defines a cavity in which the explosive powder 14 resides. The lid 16 is formed from a suitable material, such as paper or card, and is positioned over the explosive powder 14 by way of sealing against the upstanding wall 12 or by a friction fit with the upstanding wall 12.

In one example, the explosive powder contains an impact initiated pyrotechnic composition which comprises 32% charcoal, 48% potassium chlorate, 4% acaroid resin, and 16% thiourea with all percentages being by weight. In a preferred embodiment, this composition acts as an “ignition composition”, and is used in conjunction with a secondary, “signal” composition which enhances the visual effect of a strike on the target by a projectile. The secondary “signal” composition may be as follows:

Potassium perchlorate 66%, Aluminium Powder, 28%, and acaroid resin 6%, all percentages being by weight.

The two compositions are wet milled to achieve full incorporation and granulated to form random cylindrical grains of varying lengths having an average diameter of 1.7 mm. These dimensions and the integrity of the grains are confirmed by separate screening, with over or under-sized or poorly compacted grains being removed. The subsequent compaction within the housing further ensures that physical integrity is maintained. A typical blend is 70% by weight of the ignition composition and 30% by weight of the signal composition.

When used in a target of the invention, the blended composition described above is capable of being impacted initiated by a projectile and provides a slow burning, bright but gentle white flame with a white smoke signature. The effect is not dissimilar to a theatrical stage effect with sparks produced and incandescent debris projected up to 1 m of the firing point. Greater or lesser effects can be produced as desired.

In representative examples, the target has a diameter range 40-90 mm and a depth in the range 10-15 mm, with the charge weight of the blended composition being 8 g or less. However, it will be understood that targets of the invention may be smaller or larger than these dimensions, and that different charges will be used in accordance with the precise nature of the composition and intended application.

The present invention also provides moving targets such as clay pigeon type targets. A clay pigeon target may incorporate one or more housings for the pyrotechnic composition which may be similar to the housing in FIG. 1 or at least share some similar constructional principles. Further details concerning the construction of these and other moving targets can be found in WO02/35175, the entire contents of which are herein incorporated by reference. Alternatively, it may be possible to produce clay pigeon targets which do not require the use of a housing to contain the pyrotechnic composition therein.

 

[mabuse00]

 

Red P on the tip of the bullet?? Really? I hope we don't need to discuss the reasons why that would be a bad idea

 

Just a quick idea.

 

But - why should this be a bad idea? I did not meant any composition - just pure Red P - why not? The critical composition would be created only upon impact. My only worry would be barrel corrosion if the P is not bound/contained properly.

[dave321]

surely that is the same as

United States Patent Application 20100275802 by green and mulvihill (uk)

 

whats with baker and daniels ???

[Mumbles]

Baker and Daniels is the correspondence address for the US patent. I suspect that since the Green and Mulvihill are based in the UK, they need to use a law firm as a proxy physically located in the US for their patent.

[rogeryermaw]

 

Just a quick idea.

 

But - why should this be a bad idea? I did not meant any composition - just pure Red P - why not? The critical composition would be created only upon impact. My only worry would be barrel corrosion if the P is not bound/contained properly.

you could always just shoot tracers.

[Jakenbake]

As far as tracers are concerned, the comp is on the end of the bullet next to the powder. That way it gets lit from the powder charge. I would also imagine that's so you can see where the bullet is going and the enemy won't.

 

As far as putting Red P on the tip of the bullet goes, corrosion would be the least of my worries. With todays semi auto actions and even bolt actions if loaded from a magazine. The loading of the action scratches and bangs up the front of the bullets. I know I wouldn't want to experience an out of battery ign. even if it is from a 22. On a tube type magazine style rifle (mostly auto loaders and lever actions) Those only shoot flat bullets for a reason, so the recoil won't set off the primers.

 

If you have Red P laying around and not really too scared of getting fragged in the face then go for it. I on the other hand will use the same comp with Antimony in it and not have to dick around drilling bullets.