Posted 01 March 2004 - 12:08 AM
Posted 01 March 2004 - 04:49 PM
Posted 01 March 2004 - 05:52 PM
Mortar: 25mm ID by 18cm inside length (21 cm total length - 3cm plug). 2mm fuse hole
Projectile: Paper can shell casing partly filled with sand. OD: approx 24.5mm. Basically as close a fit as possible in the mortar, but not so tight it wouldn't drop down. Length: 6cm. Weight: 20.00g
Charge: 2.00g of 0.75 to 2mm barbeque charcoal BP.
I fired this pointed straight up. The shell lifted hard, to say the least - big THUMP. I guess it was quite dense. I don't have a stopwatch yet, so I just counted seconds. It spent about 5.5 - 6 seconds in the air. I'll need a stopwatch for the final test - this was, as I say, just preliminary. For the real test, I suggest sieving the BP to 1.5-2mm, partly as that way everone's grain sizes will be more similar, and partly as the shell lifted very hard. If, like me, you don't have all the correct sized sieves, I suggest drilling holes in a yoghurt pot, or something like that. Apart from that, I think that this could work OK as the standard way to do this. Any objections?
Posted 01 March 2004 - 06:55 PM
Posted 01 March 2004 - 08:24 PM
I suppose other variables I should have mentioned include moisture content of the powder and ambient temperature. Eliminating variables may make the trials fairer, but theoretically, if you eliminate all variables, everyone will get identical results. Clearly, that is not what we are trying to achieve.
I think we all agree that everyone?s powder should be of roughly the same grain size, as whilst finer grained powders would probably lift the shell higher in this scenario, that does not necessarily make them "better" powders, it just means that you used a finer sieve. However, better charcoal would produce a powder that would lift a shell higher too. Does everyone therefore have to use the same charcoal? Probably not, as increased charcoal quality may well be the result of greater skill as a charcoal maker. Therefore we have to differentiate between an variable that should be eliminated, and a variable that shows the skill of the powder maker.
Apart from the obvious - powder quantity, shell weight, mortar length etc, I think it may be a good idea if everyone?s powder was at roughly the same temperature, eg room temperature, which is probably not far off 20 degrees.
However, I think that such variables as milling time, moisture content, charcoal type, grain density and grain shape are more representative of the quality of the powder, so should be left to everyone?s own personal taste.
Finally, there is powder composition to consider. IMHO, this is a little more mixed. Obviously something like H3 is going to send a shell far higher than the same amount of BP, so shouldn't be allowed in the competition. Similarly, catalysts such as red iron oxide may improve the performance of the BP, but is it still BP? Again, probably not. However, as I mentioned previously in another thread, my best BP is 70:20:10. Should this be allowed? I think it should, since it is still a black powder mixture by definition, and in some ways falls into the same category as the charcoal - different performance as a result of different, but none the less acceptable chemical composition. I hope I'm not being too subjective.
Please add anything you think should be considered, as well as your thoughts on electrical firing. Plenty of people have expressed some interest in this competition, so; your thoughts please...
Posted 01 March 2004 - 10:40 PM
Unless we are going to meet and all shoot with the same equipment it isn't a competition, rather just a discussion of the practices we find makes the best BP. I think stop watch timing from the sound alone is fine for getting a general idea. If you always test with the same equipment then you are only trying to beat yourself, which is probably best anyway as there is no way we can prove someone's claims unless we test it ourselves on the same gear.
Edited by alany, 01 March 2004 - 10:42 PM.
Posted 02 March 2004 - 10:02 AM
I think that the electrical firing/timing circuits should be held off now, but should be used if we ever do manage a forum meetup.
Actually this would be a fine activity for a meet as we can make the environmental variables [temp/humidity etc] constant for everybody.
Gentlemen - Start your ball mills....
Posted 28 March 2004 - 10:24 AM
And it is more powerful if you do it opposite
atomized Mg 90%
Ofcourse mix it well.
Posted 28 March 2004 - 10:39 AM
Posted 28 March 2004 - 10:46 AM
BTW, I haven't forgotten about this BP testing idea, only I haven't got a stopwatch yet. Has anyone else done anything?
Posted 28 March 2004 - 01:40 PM
I made a batch or two of benzolift and was totally blow away with how powerful it is for how trivial it is to make. If anything, its a little too powerful, I think at the back of my mind I am thinking "this is 80% whistle, use to much and you'll have a DDT you idiot!" but it seems to stay on the burning side of things for less than 20 g charges - the largest I've tried so far.
The big advantage I've seen is you just screen together the ingredients and granulate, no milling required - which of corse was the whole point of experimenting with it. It also burns about a kilo kelvin hotter than BP. On the bad side, it takes potassium perchlorate which is more expensive than potassium nitrate and sodium benzoate is a waxy bitch of a substance to work with.
I also can't get over my lift looking light grey.
Posted 28 March 2004 - 03:27 PM
alany: I saw your mine video - quite a muzzle report from that 10g charge (probably wasn't so great at the time though, I guess ) Nice result from the 5g one though.
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