Author Topic: recomended powder charge (Read 979 times)

john pike · « **on:** October 25, 2005, 03:16:57 PM »

what would the recomended powder charge be for a 1/4 scale howitzer

id like to do a firing,

i have FFG powder,
and teaspoon measuring instuments,
sorry no scales,

blank fireing, for the noise factor,
and
(with a .50 lead ball for future refrence)
thanks,

johnp

Cat Whisperer · « **Reply #1 on:** October 25, 2005, 04:05:23 PM »

Quote from: john pike

what would the recomended powder charge be for a 1/4 scale howitzer

id like to do a firing,

i have FFG powder,
and teaspoon measuring instuments,
sorry no scales,

blank fireing, for the noise factor,
and
(with a .50 lead ball for future refrence)
thanks,

johnp

I ASSUME it's .50 caliber and is made from steel?

I would treat it like a .50 caliber muzzle loading pistol - if it's built to the same or better dimensions and materials.

My .50 black powder rifle barks right much loudly at 90 gr of FFg. Never done blanks in .50 cal. That might be too much for yours, don't know without looking at the dimensions, materials and geometry of the inside corners. 90 grains kicks a bit too.

But as Switlick says - start at a load that is ABSURDLY small and work up.

Which is good advice - you know roughly the charges used by similar shootin' irons and you might find one with less charge that gives adequate noise for the occasion (of course less than the max charges).

Blaster · « **Reply #2 on:** October 26, 2005, 04:30:14 AM »

John, some time ago, I purchased a nice little .50 "Enfield" from Cannon-Mania and have yet to shoot it. I did call the fellow who built them for Cannon-Mania, asking him what the recommended powder charge should be. He told me that it'd take a comparable charge as the Thompson Center "Patriot" pistol. Off hand, I don't recall what that is but if you want, I'll do some research (hunting through my stack of papers) and get back with you. Let me know if you are interested. Blaster (Bob in So. CO)

GGaskill · « **Reply #3 on:** October 26, 2005, 01:46:32 PM »

I favor one caliber charges for shot; that is, the length of the charge is equal to the caliber (diameter) of the bore. Try that out by measurement before shooting so it doesn't work out to an excessive looking charge. I am guessing it will weigh between 20 and 25 grains, which doesn't sound too heavy. Since you are limited to kitchen measuring spoons (you really should at least get a set of Lee dippers, and a simple reloading scale would be much better), try a level 1/4 teaspoon and if that isn't loud enough, try a level half teaspoon.

Terry C. · « **Reply #4 on:** October 26, 2005, 02:06:01 PM »

In my experience, the limiting factor in very small guns is usually recoil. If you want any semblance of realism, I think you will find loads approaching a 'normal' muzzleloading in a firearm of similar caliber to be excessive.

Also, ditch the teaspoons and get an adjustable powder measure. Most inexpensive (less than $10) measures for BP rifles will hold up to 120 grains, more than adequate for your cannon.

uz2busmc · « **Reply #5 on:** October 27, 2005, 10:48:41 AM »

From my experiance with a small .69 cal, 90 grains will be severe as far as recoil goes in your .50. The cannon I shoot is roughly 9 lbs. so if yours weighs less than that, expect some recoil. I don't mind the recoil, actually kinda like it, but you will surely have to accomadate it if you don't want to get your cannon dirty. As an example, my cannon will roll completely off an 8' peice of plywood with about 75 grns of 777. (firing a ball)

Also the manufacturer of mine says that I must patch the ball to fire it, not an option...

Also.... have to ditch the kitchen spoons... a little bit of powder makes a good bit of diff in these little cannons... you really want to have some kind of idea of what you are putting in there from one shot to the next, especially working up loads!

CrufflerSteve · « **Reply #6 on:** October 27, 2005, 11:56:26 AM »

A teaspoon simply doesn't make it for measuring the smaller cannon loads. A really nice measure is the U-View by TC
http://www.tcarms.com/TC_HTML/accessrs_powder.htm

It doesn't cost much and I've found it to be very handy when I'm experimenting with different loads or shooting different BP cannon/guns. If you have a local store that caters to BP shooters, they very likely carry it. If not you can find it online.

Steve

Blaster · « **Reply #7 on:** October 27, 2005, 12:13:41 PM »

Although John didn't come back and ask for it, I went ahead and dug up my information on the powder charge for a .50 BP cannon which was furnished by the fabricator of the little cannon. It was 25 grains of FFG for ball loads (NOT patched) and 50 grains of FFG for salute loads. These were only suggested loads. If not interested, no problem, merely disregard the above. Blaster

uz2busmc · « **Reply #8 on:** October 27, 2005, 12:26:38 PM »

CW,

On the insid corner geometry, how should it be shaped? I assume rounded, but is it necessarily weak if it just simply the shape of the bit used to bore it out?

john pike · « **Reply #9 on:** October 27, 2005, 12:43:53 PM »

Quote from: blaster

Although John didn't come back and ask for it, I went ahead and dug up my information on the powder charge for a .50 BP cannon which was furnished by the fabricator of the little cannon. It was 25 grains of FFG for ball loads (NOT patched) and 50 grains of FFG for salute loads. These were only suggested loads. If not interested, no problem, merely disregard the above. Blaster

Thanks everybody,
im heading up country to a BP store, next week, ill pick up the nesasary "tools"

johnp

Cat Whisperer · « **Reply #10 on:** October 27, 2005, 01:01:53 PM »

Quote from: uz2busmc

CW,

On the insid corner geometry, how should it be shaped? I assume rounded, but is it necessarily weak if it just simply the shape of the bit used to bore it out?

If one bores the bore to a diameter and then sharply reduces the diameter at the bottom - like the transition to the powder chamber or either straight across to make a flat bottom or at some angle as that of a drill bit - the sharp transition is a 'stress riser' - a weak point where stresses are concentrated - weaker than the surrounding material.

On the other hand, as you have correctly noted, a rounded corner, will spread the stresses over some distance - a greater distance with a more gentle curve - not raising the stresses and maintaining strength.

Obviously one is good and one bad in design.

Further, the surface finish, if smoother, is stronger as a crack can START at a very small point.

GGaskill · « **Reply #11 on:** October 27, 2005, 01:15:08 PM »

On the insid corner geometry, how should it be shaped? I assume rounded, but is it necessarily weak if it just simply the shape of the bit used to bore it out?

There are several issues here--strength, thoroughness of sponging and construction, at least. Sharp corners are bad for the first two and good for the last one. A sharp corner causes stress to increase in the corner which challenges strength and may also contribute to stress corrosion cracking in materials prone to that. A sharp corner is also harder to clean combustion products from, with the potential for unextinguished sparks causing a premature ignition of a subsequent charge (a very undesirable event.) Obviously since ordinary drills have a sharp corner, that is the easiest kind to produce.

If you are making a chambered bore, it is possible to drill the main part with an ordinary drill, followed by the chamber to almost maximum depth, then substitute a ball nose end mill of proper diameter to cut the bottom of the chamber to a hemispherical shape. You will need to make an extension end mill holder for this. If you can find an end mill with rounded corners, that would work also and the chamber would be a little easier to sponge.

If you are making a straight bore, about your only ready option is to drill to near final depth and then regrind the point of the drill with round corners, followed by finish drilling the bore. You probably will want to regrind the point to normal configuration after finishing the bore unless you plan to make more round cornered holes.

Cat Whisperer · « **Reply #12 on:** October 27, 2005, 02:19:05 PM »

>> On the inside corner geometry, how should it be shaped? I assume rounded, but is it necessarily weak if it just simply the shape of the bit used to bore it out?

WITHOUT QUESTION, absolutely! It may be slightly less stress causing than a true 90 degree corner to a flat bottom (included angle on jobber drills is typically 118 degrees - which makes the side to bottom angle 121 degrees instead of 90.

What is most important is the size of the radius, as the stress is spread out across it. That means a zero radius has VERY high concentration of stresses where the sweeping radius spreads the stress over more material.

If you can afford (real life IF) two drills, sharpen one with rounded corners to finish the job, otherwise one can resharpen.

Double D · « **Reply #13 on:** October 28, 2005, 03:55:59 AM »

John,

The size of your powder chamber will determine the size of your load. The maximum recommended load for 1/2 inch cannons is 40 grs. That comes from the chart for miniature cannon in Switlik's book The More Complete Cannoneer.

Blaster · « **Reply #14 on:** October 28, 2005, 02:01:09 PM »

Quote from: Double D

John,

The size of your powder chamber will determine the size of your load. The maximum recommended load for 1/2 inch cannons is 40 grs. That comes from the chart for miniature cannon in Switlik's book The More Complete Cannoneer.

DD: Is the 40 grains for a salute charge or ball? Also, 40 grains of FG or FFG? I would presume, of the two, it would be FFG. Oh yes, an empty powder can is not necessary for your reply. :wink:
Blaster