Cannon Charge Question

[buickgs]

Greetings all.
Great site and full of useful info. I’m new to Cannoneering and would greatly appreciate some advice on loading techniques. I finished building a replica of  U.S. Constitution Deck Cannon. Barrel is ½ scale with 1 ½” bore.
Here’s the problem: Half  the time I get a very loud and sharp report with a nice fire ball, but the other half  I get a muffled “pffft” sound with almost no fire ball. I’m using Pyrodex RS. I roll the powder charge container using 3 layers of heavy foil and fill a thin plastic sandwich bag  with 1.5 oz powder and place it in the foil container. Both ends are pressed tight. I insert the charge and lightly seat it with the ram. I then wad up a single sheet of paper towel and lightly tamp that on top of the charge. No projectiles are used.
I do this exact same procedure each time, but half the time I get a dud firing. I have tried tamping a little harder, and also a little lighter but no difference. I must be doing something wrong to get these dud sounding reports. This is getting very frustrating (and embarrassing in front of my gang of friends), so any suggestions are truly welcome.
Rick

[Doc Brown.]

I think you need more wadding.
I would wonder how safe plastic sandwich bags are! Sounds pretty staticy elctrictyish.

PS  Your small font gave me a migraine.

[flagman1776]

Pydrodex is poor for blank charges...  Use real black powder & you'll get a proper report.  Wadding is not necessary with black powder.  Baggies are suggested by some but I prefer not to use them & a well formed foil is pretty water tight.
Do you use a pick to insert your fuse into the foil cartridge?

[Artilleryman]

Rick welcome to the board.  I agree with flagman, Pyrodex doesn't work well for blank charges.  Use blackpowder instead.

[Doc Brown.]

Does your cannon have a reduced powder chamber?

[GGaskill]

If you have to use Pyrodex (you live in some benighted political jurisdiction), you will need to put some kind of a dummy shot in front, like an equal weight of corn meal (or some other finely grained, relatively non-combustible material) to get the pressure up.  Make a corrugated board wad of friction fit tightness to go on both sides of the corn meal.  Seat each wad firmly once; do not pound.

Your ejecta will be about as harmless as possible (still point in a safe, unpopulated direction) and you should get a good report.  Best to try alone before showing to your friends.

Otherwise, real black powder is by far a better propellant, even for blanks.

[subdjoe]

I agree with the comments about using real black powder rather than the substitutes.  And for a good "BANG" you shouldn't need any wadding.  Just firmly tamp the charge.  Two, maybe three firm strokes is enough, you don't need to pound the snot out of it like you see so often on Youtube videos. 

I'm wondering if there might be a rough spot in the bore that is tearing open your cartridge.  I've had one or two break open part way down and give a weird report, half way between a Poof and a Bang. 

[buickgs]

Thanks to all of you for your very helpful comments. Great group of folks.
 
Looks like the consensus is to use black powder instead of Pyrodex. I'll definately try it when I fire it next, and without any wadding.
 
In answer to the questions posted: Flagman, yes I use a vent pick and insert the fuse through the foil. Dockholiday, no the powder chamber is not reduced. The bore is straight 1 1/2 inches back to the breech. Subdjoe, I can't see any rough spots in the bore. The barrel is new with a stainless steel sleeve and the spent foil cartridges come out pretty much intact.
 
The best price I can find for black powder on the internet is $116.00 for 5 lbs. (Goex Cannon Granulation). Anyone find it for less?
 
Thank you all,
 
Rick

[Doc Brown.]

I don't know if your price is counting shipping. If not then you might get it a little cheaper here.
 
http://www.grafs.com/retail/catalog/vendor/vendorId/39
 
Unfortunately this place sells out fast. They had 1F earlier today but now they are out.
 
I have never purchased from them so I cant vouch for them. Where I live you can buy black powder on every street corner. 

[Double D]

$116 looks like Powder Inc, price and that includes shipping and Hazmat fee.  That's a pretty good price.

[onegreatshot]

Double has it right, They also ship in a nice hvy box.

[5kwkdw3]

I use Pyrodex P for all my ordinance (blank charges only) as this was what was suggested by the maker of my BNA mortar (my first piece) who also included a powder scoop (that held 1200 grains of powder).  He sent a few corks to pop off and told me they were number 22 corks.  Trouble was the cork was in itself a projectile and I didn't want to be lobbing out anything that could hit anything, cork or not.  After my four corks were gone I went about figuring out what wad to use.  I ended up with a disk of cardboard stapled and hot glued to two pieces of 3X5 card stock.  One on top and the other on bottom.  The cardboard was the strength and the card stock was the gas seal.  Worked like a champ with a consistent report each and every time.  We're talking loose powder here (no aluminum foil or baggies at all).  No duds at all. Each and every time I lit the fuse I got what I was after, a nice loud boom.  Perfect for the fourth of July.  Smithy.