Powder chamber?

[PAC762]

I'm a new member in the process of building a black powder muzzel loading cannon.  It is going to have a 1.75" bore and I intend to shoot mostly golfballs from it, at least until I find a range I feel is safe enough to shoot lead.  I am a little confused about powder chambers, though.  Are they only foe mortars, or do cannon use them too?  If I need to mill a powder chamber into the breech plug, what dimensions should it be?
Thanks,
PAC

[GGaskill]

Chambers (reduced diameter sections where the powder charge was located) were used in mortars, howitzers and Columbiads, so they were not uncommon.  For dimensions, you need to figure out what powder charge you want to use, then calculate its volume, then calculate a convenient diameter and the appropriate length to get that volume.

I have been using 1" ball end mills for chambers to get the hemispherical end but you need to make an extension holder.

[kappullen]

Pac,

I hand grind a drill into a "Russian grind". The Russians in days gone by
ground round points on drills because the chips tended to break instead of making curls.

In any case, a stabilizing bushing may be required to minimise chatter
with your extension mill, or drill holder.

Kap

[freddo]

Kap- I would be very interested if you could enlarge your description of the stabilising bushing that you mention.

[CU_Cannon]

I also use a 1” ball end mill.  I drill the chamber to 7/8” then finish it with the end mill.  One of the keys for a good finish is to use lots of cutting oil and a slow spindle speed.  Also make a holder that is as big as possible.  The holder I used of my golf ball mortars is 1 1/2" diameter.

[PAC762]

Thanks for the help.  I have the necessary tools to do a 1" hemi chamber.  However, my cannon will be a howitzer type (I think.... whatever the name for a direct-fire cannon is.).  Do those type use chambers as well?

[GGaskill]

A howitzer is a middle length tube capable of relatively high angle fire; they were typically chambered.  A cannon (or gun) was typically a long tube and it was mounted such that its maximum elevation was less than 10 degrees; they were not typically chambered.

[Rickk]

before you go the chamber route, if you make a powder chamber in it, and it is not a mortar (pointed 45 degrees up), ask yourself (or others) how are you going to get the powder into the powder chamber?

A howitzer has some angle to it, which will help keep the charge in place, but if you are thinking powder chamber to keep the charge down to keep the range down, a howitzer angled upwards might be counter productive to distance control.

Of course, putting all that aside, I guess if you plan it out from the beginning with the possibility in mind, if it doesn't work out you can always open the chamber out to full bore.

My 2.25 inch mortar does not have a powder chamber. I sort of wish it did for short range target practice.  I can back it down to about 1/3 of an ounce of Cannon Grade before I have issues with irratic ignition. At 1/3 of an ounce, a 2# lead ball goes about 60 yards. At 1/2 ounce it goes about 100 yards. With charges under about 3 ounces in a 2.25 inch bore there are "techniques" needed to make the charge go in straight.

 My firewood cutting pattern is "wierd" this year "for some reason". For some reason, I am cutting in a long, narrow path, and am at about the 60 yard point right now. A couple more days and I may hit the 100 yard mark. :-)

[GGaskill]

A number of my artillery pieces have 1" diameter chambers.  The trick for inserting an aluminum foil powder bag is to use a loading tube, which is a piece of 1" copper pipe at least a hand width longer than the bore.  Insert the powder bag near the end of the tube, insert the tube in the bore up to the front of the chamber, push the powder bag into the chamber with the rammer through the tube.  Remove tube and rammer.

[PAC762]

Thanks everyone!  I intended to load with foil, as I have loaded other cannon in the past.  I guess I should say this is a "gun", as it will be intended for direct fire with less than 10 degrees elevation (I'm actually planning to scope it).  I will leave the chamber plug without a chamber.

Thanks again,
PAC

[Rickk]

If you go without a chamber and want to shoot reduced loads, they will be very short and hard to get to go in correctly... they will tumble and sometimes wind up going in sideways. That leads to inconsistancy between shots. You can tape them to the back of golf balls with masking tape to get them to go in straight... it has been workig for me.

I use a "u-shaped" ramrod to avoid having my hand anywhere near the muzzle while loading live rounds. It works for blanks as well.

A thing to be happy about with no reduced chamber is that you can make bigger blank loads and make a bigger bang... and bigger bangs are a lot of fun :-)

[Cat Whisperer]

...
I use a "u-shaped" ramrod to avoid having my hand anywhere near the muzzle while loading live rounds. It works for blanks as well.
...

EXCELLENT IDEA.

I know from experince that the muzzle blast from my 4.5 will snap a 1x4 next to the muzzle!