The whole story of explosives

M9Powell

Ad Honorem
Oct 2014
4,416
appalacian Mtns
#11
Gambrinus is correct , smokeless powder is acting as a deflagration ..ie subsonic
TNT and other true explosives act as a detonation ie supersonic

Smokeless powder was still much more brutal than black powder and the rifles Breeches had to be reinforced
this also led to using much smaller caliber , going from , typically , 0.43 inches to 0.303 for a greater velocity and range

the German Panzerfaust used black powder as a propellant to have a smoother , slower burn to propel the charge
Smokeless powder is a propellent, but it is supersonic. Some of it is 5000 fps, well above Mach 4.
 

sparky

Ad Honorem
Jan 2017
4,331
Sydney
#12
the deadliness of a weapon system is not what qualifies as "weapons of mass destruction "

Thermobaric weapons are weapons ,
weapon pf mass destruction are Atomic Biological Chemical
or in military parlance ABC when talking of ABC protection

the last two are forbidden under international treaties , while the first is also under restrictive set of treaties
nuclear weapons are explosives ,
their main military effect is in order of what get you
- flash , pretty immediately
-parcticles of the Gamma type
-shock wave , seconds later depending of the distance

the radiation effect of the particles and residuals are not really wanted and are more of an embarrassment
some weapons have been developed to irradiate the target area for a long time
but they have been largely rejected as being both immoral and inefficient
 

sparky

Ad Honorem
Jan 2017
4,331
Sydney
#13
" Smokeless powder is a propellent, but it is supersonic. Some of it is 5000 fps, well above Mach 4. "

you got me into the strange and wonderful world of reloaders
could you point me to some good data , I see that the Norma R-1 is reputed as the fastest ?

I know that for artillery , they use rods of various diameters to slow down the explosion of the propeller
this is to have a smoother pressure profile and avoid a too sharp spike , which is not really helpful and damage the chamber

Black powder guns had the same issue and used different grain size depending on the intended use
different woods were used to get different charcoals shapes
coarser grain were for artillery , medium for long firearms and somewhat finer for pistols
for those last two I know that is done in modern Black powder shooting
the really fine was the priming powder
Dupont had a range of grain size for shooting or construction or quarrying
 

M9Powell

Ad Honorem
Oct 2014
4,416
appalacian Mtns
#14
I like Hornady & Sierra data. Think about it though. A bullet can be propelled too around 4,000 fps with smokeless powder. The expansion of the powder has to be faster than the bullet. Handloading is a more accurate term nowadays than Reloading although either is acceptable. The biggest reason for handloading is not cost savings by reusing components. It is to either obtain something unavailable from major manufacturers or too increase precision far above what is available from mass production.
 
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sparky

Ad Honorem
Jan 2017
4,331
Sydney
#15
So ok the speed you are referring to is the muzzle velocity of the bullet
Better not go in those waters , but I get you point
 

M9Powell

Ad Honorem
Oct 2014
4,416
appalacian Mtns
#16
What's wrong with those waters? AFAIK the fastest commercial load is a 30-06 load by Remington containing a 22 caliber bullet in a Sabot. I don't remember the exact velocity but it's around Mach 4. Does anyone know the velocity of an Abrams tank round or is it still classified?
 
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sparky

Ad Honorem
Jan 2017
4,331
Sydney
#17
Muzzle velocity depend on the propellant nature and charge
but also on the diameter to length ratio
when the charge is ignited , a solid is changed into a gas
IE 5 grain of powder is changed into 5 grain of gas
on top there is a very elevated temperature which increase the pressure further

a bullet is accelerated from zero to the final exit speed along the length of the barrel
the back pressure decrease from the initial value while the bullet is traveling faster
the longer the fastest ...up to a point when the air resistance overcome the charge push

in the case of a very long barrel with a heavy projectile
a slower burning charge provide a longer force while being easy on the chamber

the optimal diameter to length is somewhat less than 100/1 for rifles
it often is lower to decrease encumbrance since the effect is marginal

in the case of hand guns a fast burning charge is needed since the initial velocity is all important

The M256A1 gun is the Rheinmetal Rh120 ( German are good at designing tank guns) with a muzzle velocity of 1700m/s , or a bit less depending on the ammo
it's a smooth-bore to shoot Heat rounds and use sabot for penetration targets
1700m/s is roughly equivalent to Mach 6.6
 
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sparky

Ad Honorem
Jan 2017
4,331
Sydney
#19
Well , there is the wear of the barrel to consider and the inertia of the projectile
for HEAT round , speed is only needed for the flatness of the trajectory , modern targeting do most of the job now
it's all about adjusting the powder charge and type to the intended use
people have been fooling around with the physic of the explosives for centuries
in mining they even have explosives who don't explode !
they just expand very quickly , are put in drilling holes to break the stones and are used in close proximity of miners