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Discussion Starter #1
Not mine. Custom-made 3" bore, 1700 lb. 20pdr Parrott pattern, 1/2 in. steel liner. Projo was dogfood can filled with concrete, duplex charge of 1 lb. FG plus 2 lbs. of black powder from 155mm igniter bags.

Obviously the mounting is unique. I guess this is a "towed gun?"








 

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The 20 pdr took a two pound charge, and the 10 pdr (3 inch) took a one pound charge. I have no idea what the characteristics are for the 155mm igniter charge powder. For myself, I would have to a pretty good reason to use a duplex load in the first place.

This is an interesting situation. A one pound charge of Fg behind a 9 to 11 pound projectile would be a service charge for a 3 inch gun. Here we have a 20 pdr sub-calipered to 3 inch firing a light weight projectile using a duplex powder charge. Since the 20 pdr took two pounds of powder and a 20 lb projectile for a service load I wouldn't have a problem with firing up to two pounds of powder in this gun assuming that the barrel was poured solid and bored before being sleeved. In practical terms though it would just be a waste of powder to go beyond 1 lb.

My question is, what is 155mm igniter black powder?
 

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The 155mm howitzer is separate loaded. Meaning load the bullet, load the powder, close the breech, and prime.

When the charge is 'cut', the unused charges are removed. Firing charge 7 means that all 7 charges are there. Charge 1 is large, charge 7 is very small (individual charges).

Charge 1 has a red end - it contains a thin layer of black powder. The red end is on the end exposed to the breech block, hence exposed to the tube leading through the breech block to the primer. The primer looks like a brass .410 cartridge. The red end of the powder sack catches the sparks from the primer and ignights the main charge.
 

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Discussion Starter #6
The black powder from tbe igniter bags looks to me to have larger average grains than cannon grade. There's a separate discussion you may want to look at to see the screen size range of the "Class I-A" military black powder that is used in the igniter bags. I have some and if I can get it next to some cannon and FG for a photo-shoot sometime soon, I will do so.

It also seems to me to be a lot of powder for the projectile used. I'm guessing the projectile weighs no more than about 6-7 lbs.
 

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Interesting recoil mechanism. I didn't notice the heavy springs at first. How much does the carriage move during recoil?
 

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Artilleryman said:
Interesting recoil mechanism. I didn't notice the heavy springs at first. How much does the carriage move during recoil?
I'm just hoping that those outer springs are retained by more than those wood blocks there - Compressed and released, springs of that size can kill you as dead as a cannon ball would.
 

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The wood block is just a spare wheel chock lying there. The guy who had this built has been shooting it for many years. The carriage has been improved over time, but he's always had that particular recoil mech, at least during the past 10 years I've seen him show up at the event where I took these pix (Knob Creek KY Machine Gun Shoot.)
 
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