Changes made to link...no longer active...... hope this is ok ? Please view....
http://cgi.ebay.com/BLACK-POWDER-CANNON-MORTAR-SIGNAL-CANNON-NOISE-MAKER_W0QQitemZ170223740901QQihZ007QQcategoryZ73979QQssPageNameZWDVWQQrdZ1QQcmdZViewItem I note that some seem to think that modern steel and black powder limitations would make this a mortar or "thundermug" that would not explode, but another valid point was made that in the light of previous information make it almost as bad as if it would blow up,and that is the observation of it's base and height, after reevaluation the dimensions which are as follows
BARREL LENGTH 7 3/4" INCH. BARREL DIAM. 2" INCH. BORE DEPTH 6 1/2" INCH. BORE SIZE 1" INCH 1 1/4" INCHES DEEP THEN DROPS DOWN TO .6540 POWDER POCKET 5 1/4" INCHES DEEP.
Now heres the math that makes this dangerous in my opinion ,with a powder pocket of .6540 that is 5.25" deep this allows for a BP load of 2fg that is 793.1385 grains or just under 2 ounces, I arrived at this figure using the fact that 1 cubic inch of space will hold 231 grains of 2fg BP ,the bore diameter of .6540 multiplied by the 5.25" depth allows for 3.4335 cubic inches of space then multiply that figure by the 231 grains per cubic inch to reach the 793.1385 grains, and there is 437.5 grains of 2fg per ounce or 875 grains per 2 ounces.
Now I know this doesnt sound like much to the big bore gang, but it has been reported on this board more than once that a cotton rag used as a wad has been embedded in to a tree at 20 ft with about a 1.5 oz 2fg load.
So add those figures and double check my math as I am not a rocket scientist, but this size load coupled with it's obvious tipsy stature ,and you have a recipe for somebody wearing a Bandana in their head instead of on it.
I certainly dont mean to scare anyone off from making a purchase from this maker, I just would like the uninformed to be aware of the possibilities,and to always remember, anything coming out of that barrel beit it toast or the times will be a projectile for a short distance before gravity takes it's hold..... this isn't browny mix
Just remember those figures are as if the user already knows to do their powder measurement based on the powder chamber size,and follows the basic load rules for blanks, and I can't tell you how many times I've read those posts about what makes a good blank wadding,,,well in this mortar/thundermug......nothing would be the best bet, follow the rules for safe load procedures and foill wrapped charges ,and you should be okay, but if you dont..............put sandbags around it for the spectators.
I just thought this had to be said with the 4th comming up and all, there are many youngsters out there wanting to make a terrific noise,and God Bless em for it......just survive it...................
Thanks for viewing my concerns...
I have finished my second piece a modern day thundermug of what I hope is a little safer design than the one shown here, it is as simple as can be,with a couple added asthetics for Holiday enjoyment, I will post pictures tonight....
Have a great weekend all.......