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Offline Evil Dog

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The Learning Curve
« on: May 22, 2005, 02:08:32 AM »
Discovered a couple more things.... I should have used heavier wheels on my half scale Napoleon.  Currently using a set of 30" wood hub wheels... have probably no more than 50 shots fired and those wheels are already getting a bit loose.  Will probably have to replace with the heavier "cannon wheels" before the end of the year.



Those "post-it note quills" work pretty well, but the 3 strand twisted rope on my linstock really suffers from the blast coming out of the vent.  Think that I will stay with a 3" piece of American made Visco fuse.  Yes, I bought another 300 feet of it.... not that I would ever exceed 25' in a year anyway.



Zinc balls give a lot more zip at any reasonable powder charge level.  The 2 1/4" ball cast from wheelweight weighed in right around 2 pounds 8 ounces.... casting with zinc the ball now weighs 1 pound 7.3 to 7.5 ounces.  More zip with less recoil.
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Evil Dog

Democracy is two wolves and a lamb voting on what to have for lunch.
Freedom is a well-armed lamb contesting that vote. - Benjamin Franklin (1759)

Offline Cat Whisperer

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The Learning Curve
« Reply #1 on: May 22, 2005, 03:35:26 AM »
Is there any difference in wear & tear on the linstock between holding it above or to the side of the touch hole?

I wonder if there is a releationship that can be defined by a formula that relates the velocity of a zinc vs. lead sphere for the same charge for a given bore diameter?  

I don't have a chronograph, but would be very cautious on using one in front of a 4.5" OR a golf-ball caliber mortar!
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Tim K                 www.GBOCANNONS.COM
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Offline Will Bison

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The Learning Curve
« Reply #2 on: May 22, 2005, 06:22:35 AM »
Evil Dog;

First of all, let me congratulate you on launching some zinc balls down range. Sounds like you got through the learning curve of casting just fine.

I hold the linstock flat and I prime the vent with just a tad of smokeless ball powder on top of the BP. The vent is filled with BP and then the ball just on top. The ball is easier to light with the linstock. I too noted many years ago that the vent blast can make a mess out of the match cord hence I hold it to the side.

I purchased a set of old wagon wheels some years ago for a 3/4 scale Parrot. I thought I did a pretty good job of restoring them 'till about the third or fourth shot. WOW! Almost instant disassembly from recoil. That initial impulse is quite severe.

Tim;

I think a hypothetical relationship should exist between zinc  and lead balls. The first step would entail velocity measurement of both materials. Once those numbers are known, a percentage figure could be applied. I still plan on my trip to the desert this Summer to do some range and velocity testing. A blast fence of some sort will be required to protect the chrony. I tested a prototype fence last week and it failed. Got some good kindling wood for the camp fire out of it when the muzzle blast blew it to pieces.
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