Page 1 of 2 12 LastLast
Results 1 to 25 of 30

Thread: Curiosity- Formed powder charges.

  1. #1
    Member  
    Join Date
    08-23-07
    Posts
    7,959

    Curiosity- Formed powder charges.

    Has anybody here ever done experiments with rifles by making paper cartridges with the powder charged formed with a hole going through the length of the powder?

    By my calculation such a charge would burn at an ever increasing rate since as the charge burned the surface area of the hole would increase. Since the ball's travel would create a greater volume the pressure should be more or less constant during the time of travel.

    But, when the math meets real life the math often loses.

  2. #2
    Member  
    Join Date
    11-09-10
    Location
    Northern California
    Posts
    55
    Those Pyrodex pelletized powder charges have a hole through the center.

    I have never tried them.

  3. #3
    Member  
    Join Date
    08-23-07
    Posts
    7,959
    Hmmm, I'll have to see I can get some. However, my thought was to form the entire charge. It would have to be black powder considering the process necessary.

    If you are curious, I got the idea from reading about WWI navel gun propellants that were formed with a 'rosette' space inside the strip. The pressure curves shown were really wild!!! Something in the order of a bell curve.

  4. #4
    Member  
    Join Date
    11-09-10
    Location
    Northern California
    Posts
    55
    The pelletized charges look to be formed similarly to the propellant in a model rocket engine, so you are probably on the right track.

  5. #5
    Moderator  
    Join Date
    05-30-06
    Location
    North Idaho/Eastern Washington
    Posts
    1,375
    Depends on your goal. Better velocity? More powder efficiency? Easier loading?

    Experimenting on such things might have made sense back in the 1940s, when the selection of nitro-based propellants was very limited compared to now.

    BP is of course about the same now as then, but just switching from Goex to Swiss brand BP can significantly improve performance, all else being equal.

    Pressures and burning rates can be difficult to predict, as one influences the other, but there are reportedly some internal ballistics programs that do a good job. I don't know if any of them get into black powder though.

    Having a significant hollow space behind the bullet is generally frowned upon. One thing it'll do for sure, in a revolver, is reduce the maximum charge weight.

    Could you seat the bullet reliably without upsetting the "shaped charge" at random?

    Things can be counterintuitive (depending on your intuition). Last winter I tried some Buffalo Bullets "BALLets" in a Pietta Remington .44 NMA. The heavier BALLets yielded 200 fps higher velocity than a round ball with about the same charge. Details here.

  6. #6
    Member  
    Join Date
    08-23-07
    Posts
    7,959
    Hi Omni,

    The goal is better performance. Taking a product and getting more out of it than thought possible.

    According to the math such on config would have a steadily increasing pressure rather than the 'spike' of a normal powder charge. I conclude from the curve that the ball would have greater accuracy as well as muzzle velocity.

    Again, it's mainly my own curiosity. I play with math the way some people play cards. This happens to be the flavor of the week and I was wondering if anyone had done work in this area so I could pick their brain a bit. If I had an inline rifle I would try the pyrodex and do a crono but... For now I'll put the calcs in the file marked "interesting possibilities."

  7. #7
    Senior Member  
    Join Date
    09-30-03
    Location
    SW PA
    Posts
    1,808
    In a pistol charge, I'm thinking that you won't be able to measure any difference with a cored charge vs the same weight normal version. Just not enough mass of what is a low-grade explosive to make much difference in how it burns.

    In the artillery case, where pounds of propellant is being lit, the hollow core to extend the flame to the entire charge at once from the inside out makes a lot more sense.

    Years ago, I played around with cylindrical 'devices' involving up to 4lbs of black powder and various fuse locations trying to see how they burned. The central fuse location went off a lot better than from the end.

    Please don't let my comments dissuade you from your experiment as I have been wrong a time or two in the past. You might be on the brink of an earth-shattering development. Or maybe not. The experimenting IS the fun of it! Enjoy and please let us know how it goes.

  8. #8
    Senior Member  
    Join Date
    03-01-07
    Posts
    1,655
    Please don't let my comments dissuade you from your experiment as I have been wrong a time or two in the past. You might be on the brink of an earth-shattering development. Or maybe not. The experimenting IS the fun of it! Enjoy and please let us know how it goes.
    Aye, and may you keep all of yer fingers.
    When the going gets tough the tough get cyclic!
    "The Constitution is a restraining order against the federal government. I'm not going to say a word about the effectiveness of restraining orders against criminals." Standing Wolf

  9. #9
    Senior Member  
    Join Date
    07-05-07
    Location
    South Western, OK
    Posts
    1,137
    Perforated black powder grains were invented in the late 1700s. Napoleon's army used perforated grains in some of their artillery pieces. A grain with one round hole in the center is called a neutral burning grain because the burning surface remains about the same until grain burnout.

  10. #10
    Does it matter that one (BP) is an explosive and the other (Nitro-Cellulose) a propellant?

    Regards,
    Albert “Yes, I am still in Afghanistan!” Rasch
    The Rasch Outdoor Chronicles
    Don’t get Snake Bit!!! But if you do…

  11. #11
    Member  
    Join Date
    08-23-07
    Posts
    7,959
    Does it matter that one (BP) is an explosive and the other (Nitro-Cellulose) a propellant?
    *sigh*

    Black powder does not have a 'detonation zone' when compressed so is not an explosive. Nitrocellulose does have a detonation zone when compressed and is an explosive. Please note that many pistol "propellant" powders are a mixture of Nitrocellulose and Nitroglycerin and therefore are essentially dynamites.

    BP depends on burn rate to propel a ball, unlike a real explosive the burn rate cannot be adjusted chemically. Thus the idea of shaping the charge to modify the characteristics of burn.

  12. #12
    Member  
    Join Date
    08-23-07
    Posts
    7,959
    Hi Al,

    Perforated black powder grains were invented in the late 1700s. Napoleon's army used perforated grains in some of their artillery pieces. A grain with one round hole in the center is called a neutral burning grain because the burning surface remains about the same until grain burnout.
    Thank you! I didn't have that bit of information. It gives me a starting point to study.

  13. #13
    Senior Member  
    Join Date
    12-25-02
    Location
    Washington State
    Posts
    2,104
    @ O.W.:

    I am very interested in your efforts in this area. I am just starting to dabble in the blackpowder area, and it's with a black powder cartridge rifle. Here's my question:

    I have found that compressing the charge will help in loading the case to a uniform density. So far, I enjoy decent accuracy from my rifle with 115 grains of Goex 1F powder, slightly compressed.

    My problem is with lube starvation--my rifle has a 34" barrel, and I usually get a nice, hard cake of carbon parked in the last few inches of the muzzle. If I do not wet patch/brush/dry patch between shots, accuracy flies right out of the window.

    Hence, my question--will compression help the burning characteristics of the black powder, and thus alleviate the formation of powder fouling?
    Hiding in plain sight....

  14. #14
    Member  
    Join Date
    08-23-07
    Posts
    7,959
    Hence, my question--will compression help the burning characteristics of the black powder, and thus alleviate the formation of powder fouling?
    No, black powder is a mechanical mixture of fuel, oxidizer and tinder. The fouling is a complex mole of potash, sulfur and carbon that is going to form as part of the reaction. Compression slows down the burn rate giving better pressure curves but fouling is just part of the mixture you have to work around.

  15. #15
    Senior Member  
    Join Date
    09-30-03
    Location
    SW PA
    Posts
    1,808
    Powderman,

    The Brits used a bees-wax 'cookie' under the bullet on the 577-.450 Martini-Henry round. Card wads on either side of it to keep it out of the powder and keep the 'cookie' from sticking to the base of the bullet. It MUST release the bullet to be accurate....if it sticks to the base it will be dismal.

    They were using a paper patched bullet and you might get away without the bees-wax if you have enough lube grooves on your bullet. What kind of bullet are you shooting and do you have room for more lube grooves? I think the old-timers got into the same problem and ended up with 500's in the long cases so they could get enough grease on the bullet and have case to cover it until it was shot.

  16. #16
    Moderator  
    Join Date
    05-30-06
    Location
    North Idaho/Eastern Washington
    Posts
    1,375
    You might also try Swiss powder, which will typically give the same velocity with a lighter charge. My theory being that less powder mass might result in less fouling. I don't have a long barrel to test it.

  17. #17
    Senior Member  
    Join Date
    12-25-02
    Location
    Washington State
    Posts
    2,104
    Rob:

    My complete load for the rifle goes like this...

    550 grain .451 bullet, paper patched with #9 onionskin to .459. I load this on the following:

    115 grains of Goex, compressed .6 inch; overpowder .030 King's fiber wad, 1/4 inch SPG grease cookie, and another .030 sealer wad. The bullet is hand seated just prior to loading it into the rifle. These are my most accurate bullets--but then I have the lube starvation problem.

    Omnivore: I also use lubed bullets with the grease cookies. I load them following the same load order--the bullets are 550 grain bore-riders--bearing surface stops just before the meplat. I have had good luck with Swiss 1 1/2F and Goex as well, but they're just not as accurate as the paper patch.
    Hiding in plain sight....

  18. #18
    Senior Member  
    Join Date
    06-14-07
    Location
    NE Oklahoma
    Posts
    1,455
    Powderman, what ae using for lube on the bullets?
    I've jsut started down the BPCR path to damnation myself.
    Picked up a Pedersoli 1874 Sharps Business Rifle in .45-70 with a 32" barrel Tuesday. Got my mold and other misc. needs to start loading BP rounds for it today.
    Some people are like slinkies. Not really good for anything but they still bring a smile to your face when you push them down a flight of stairs.

  19. #19
    Senior Member  
    Join Date
    02-05-07
    Location
    Oklahoma
    Posts
    1,539
    I use DGL lube when I am shooting greasers. These are pan lubed. Otherwise I use a .442 bullet paper patched up to .450 in my 45-90.

    Michael

  20. #20
    Senior Member  
    Join Date
    12-25-02
    Location
    Washington State
    Posts
    2,104
    @ O.W...

    Referring to your original post, are you by chance thinking about making paper cartridges with these propellant pellets? And, if so, how would you ensure proper seating of the ball/bullet? I'm curious, because I've always had an urge to try a paper cartridge myself.

    To the others:

    For the BPCR questions, I'm going to start a thread over in the Black Powder section, so we don't jack the thread more than it has been.
    Hiding in plain sight....

  21. #21
    Member  
    Join Date
    08-23-07
    Posts
    7,959
    are you by chance thinking about making paper cartridges with these propellant pellets?
    Actually I hadn't but it's a thought. ATM the only BP rifle I have available is the 75 cal 'deer rifle' with a side lock. I'm trying to figure out how to the get the fire to travel from the side to the bottom. But, as I said before, for the moment all this is on paper and I'm trying to do a bit of fact gathering.

  22. #22
    Senior Member  
    Join Date
    12-25-02
    Location
    Washington State
    Posts
    2,104
    It seems that the ideal vehicle for this foray would be a black powder cartridge rifle. The challenge would be to find a case that would keep the pellets centered over the flash hole in the cartridge. An over powder wad, a lubed bullet seated firmly on top of the pellet or pellets, and you would be in business.

    Of course, you would be somewhat limited in your choice of cartridges, as the charge (using the Pyrodex pre-formed pellets) would be in 50 grain increments. The .45-100 and .45-110 would seem to be in order.
    Hiding in plain sight....

  23. #23
    Member  
    Join Date
    08-23-07
    Posts
    7,959
    It seems that the ideal vehicle for this foray would be a black powder cartridge rifle.
    Not necessarily, an 'inline' weapon would work well. Centering would be a simple matter of having a flare at bottom side of the pellet with a loosely packed 'plug' of 4F. The 'plug' would have the added advantage of 'flashing' the length of the core igniting the inside of the entire pellet.

    Please keep in mind my figures show having the pellet compressed much like a pyrotechnic rocket. Loading would be putting the entire pellet in the bore followed by a patched ball. With the compression I'm using (8 ton w/cornstarch binder) best results (again on paper) would be with a 48 inch barrel.

    Again, the math shows very interesting pressure curves, especially if the outside of the pellet doesn't burn the length of the barrel. Quite frankly the engineering of compressing the pellet with the core has eluded me ATM.

  24. #24
    Moderator  
    Join Date
    05-30-06
    Location
    North Idaho/Eastern Washington
    Posts
    1,375
    ...the engineering of compressing the pellet with the core has eluded me...
    Sounds like you need a set of dies made, and a large arbor press. Depending the shape of the core, it could be very simple or it could require multiple pellet elements. That would depend on draft angle.

    Just depends on your level of motivation and the performance you think you can get. If we're talking spending a couple thousand dollars on tooling, verses using 20 grains more powder (let's say) to achieve the same thing; I'd use the 20 grains. It 's a big deal in rocketry because it goes directly to that all-important launch weight-- the more fuel you need, the more power and fuel you need to lift the fuel... That's pretty much a non-issue when it comes to rifles though unless we're talking pounds instead of grains, which we aren't.

    Then again, I'm talking out of the dark here - what sort of performance difference are we discussing? Sounds like you've done some figuring, so what are you predicting happens with what ball, from what charge weight?

  25. #25
    Member  
    Join Date
    08-23-07
    Posts
    7,959
    Then again, I'm talking out of the dark here - what sort of performance difference are we discussing? Sounds like you've done some figuring, so what are you predicting happens with what ball, from what charge weight?
    In a normal loose charge, the pressure curve goes very high from the burning of the charge then tapers off as the ball traveling down the barrel increases the available volume. With the compressed charge with the piercing the pressure curve gradually rises as the volume increases from the increased surface area of the propellant burning. (this is assuming the outside of the pellet or cylinder isn't burning, only the core and the ends.) I'm wondering if this wouldn't create a difference similar to a slower burning smokeless/fast burn smokeless in a longer barrel length.

    As for the engineer aspect, I have the machinery available in my brother's shop in the form of a hydraulic press. However, my concern is the pressures involved require a steel pin and die. The nature of the product makes me nervous of the possibility of steel against steel creating a spark.

    As my late uncle was fond of saying on the subject of high energy chemistry: God in his wisdom saw fit to give you ten fingers. It would be a gesture of respect to take care to keep all ten.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •