Vicky must have a story, but she ain't talkin'

[RocklockI]

JASmith ....Good word !

sounds worth the money to me . Welcome 

a complete history of one country in a single book ...'....with few factual errors ......' , the errors mentioned wouldnt trouble me at all . thanks Cmn ! .

gary

[Victor3]

Doesn't that make a mess worse than black powder fouling???

I've put small amounts of it in the chamber to accommodate various situations and not noticed a problem; this would be more, we'll just have to try it and see.  Whatever it does, if it prevents bad pressure spikes due to voids, some mess would be tolerable.  I expect the vast majority of it will vaporize. 

We've also put hard foam rubber, very light, the kind used in 2 x 3" or larger bars used as padding in computer shipments, behind some rounds.  That stuff gets singed pretty well but comes out of the muzzle largely intact, with no residue noticed in the gun. 

 I'd use something other than styrofoam if you're relying on it to prevent a pressure spike; you want something that's not going to compress much or burn up rapidly.

 In "lost foam" casting, styrofoam vaporizes as soon as molten metal contacts it. Under the conditions in a cannon chamber, I suspect it may not be much better than air space (styrofoam being largely air).

 It is relatively clean as far as melted plastics go.

[Double D]

Foam-sponge, floral and styro, are all used as fillers in Large British blackpowder and nitro cartridges.

But do note,  Fillers are material that fill all the air space in a cartridge or barrel.  Wads simply position components and still leave airspace. Airspace is bad.

[cannonmn]

Under the conditions in a cannon chamber, I suspect it may not be much better than air space (styrofoam being largely air).

I guess to optimize the material used, I'd need to know the exact mechanism that is supposed to do bad things to BP cannons if air space is left between the charge and projectile. 

I know what happens in smokeless powder modern cannons, with charge asymmetries, but I think that's a totally different process, the standing waves etc., so I have to start over again to learn about airspace in BP cannons.   Meanwhile I'll use some kinda foam and modest charges.

[Double D]

Under the conditions in a cannon chamber, I suspect it may not be much better than air space (styrofoam being largely air).

I guess to optimize the material used, I'd need to know the exact mechanism that is supposed to do bad things to BP cannons if air space is left between the charge and projectile. 

I know what happens in smokeless powder modern cannons, with charge asymmetries, but I think that's a totally different process, the standing waves etc., so I have to start over again to learn about airspace in BP cannons.   Meanwhile I'll use some kinda foam and modest charges.

No different in BP.

The Experts will argue the theories all day long...they all insist their theory is correct...when I look at them they all seem to be saying the same thing just differently...standing wave-air compression what ever just tell me how to prevent  the issues.  Fillers is the only 100% way.  Other techniques are used but fillers is the surest.  The most common filler is powder and projectile.  Styrofoam does work, but makes a nasty mess down range...snow storm.

[Victor3]

Under the conditions in a cannon chamber, I suspect it may not be much better than air space (styrofoam being largely air).

I guess to optimize the material used, I'd need to know the exact mechanism that is supposed to do bad things to BP cannons if air space is left between the charge and projectile. 

I know what happens in smokeless powder modern cannons, with charge asymmetries, but I think that's a totally different process, the standing waves etc., so I have to start over again to learn about airspace in BP cannons.   Meanwhile I'll use some kinda foam and modest charges.

No different in BP.

The Experts will argue the theories all day long...they all insist their theory is correct...when I look at them they all seem to be saying the same thing just differently...standing wave-air compression what ever just tell me how to prevent  the issues.  Fillers is the only 100% way.  Other techniques are used but fillers is the surest.  The most common filler is powder and projectile.  Styrofoam does work, but makes a nasty mess down range...snow storm.

 Interesting... I thought it would be consumed.

 Maybe an option would be good ol' dacron batting. Never seen a trace of it after using it to hold the charge up against the flash hole in rifle cases. That's just a small amount and not tightly packed though. I wonder how it would perform in a cannon 

 Prolly better to just use oatmeal or some other cereal stuff. That would be more "green" anyway. Or grass seed.... Can't get much greener than that 

[cannonmn]

oatmeal or some other cereal stuff. That would be more "green" anyway. Or grass seed....

Depending on the type of projectile I begin trials with (probably a non-studded right circular cylinder) I will need wadding also which will at least partially seal the grooves upon firing, or I'll be wasting a lot of expensive BP energy.  Would be nice but not mandatory if the same material would serve both functions, seal grooves and fill up airspace.

[Victor3]

 Aluminum foil wad on top of the charge, with grass seed filler?

[KABAR2]

What about using some inert substance invented by man that has on real use would be bio-degradable (Cough...Spit) and the birds might eat it..........................





I give you the perfect filler nearly indestructable with no other legitimate use................





The lowly puffed rice cake!

 

[Double D]

 Interesting... I thought it would be consumed.

 Maybe an option would be good ol' dacron batting. Never seen a trace of it after using it to hold the charge up against the flash hole in rifle cases. That's just a small amount and not tightly packed though. I wonder how it would perform in a cannon 

 Prolly better to just use oatmeal or some other cereal stuff. That would be more "green" anyway. Or grass seed.... Can't get much greener than that 

Not consumed, blown out the barrel.

Dacron batting works, but must be tightly compressed to work right.  I use kapok all the time for filler in 577/450. 

In this application, for reasons of pure simplicity, I'd go with styrofoam

[KABAR2]

O.k. a couple of days ago I announced I had a thunk......  I think......... well anyway here it is...........

there was talk of using PVC as a projo. I think that PVC pipe could also be cut and provide the studs,

this is a quick mock up of what I am talking about on a piece of 3" PVC,

it would of course be filled with concrete and use a plywood sabot on the base.

[cannonmn]

Thanks Allen, good idea.  I'm not sure those little screws would withstand the forces caused by rotational inertia, but of course stouter hardware would be used in a fireable version.

[KABAR2]

Yes this is only a mock up,  I wanted to see how hard it would be to set this up if done properly I think with a stout bolt and nut being used  this would work fine,

actually I am thinking  a mold made to cast the studs in for consistency could be made, the bolt could be cast into the middle of each stud this way the bolt will be

sheathed so it can not gall the rifling.  then it is only a matter of drilling holes and bolting them on.

On the matter of the chamber filler,  we have been die cutting foam wads from a rather stiff foam and using them as a wad over the charge in black powder loads

in someone's 50 mm KRUPP,  if you can get me the chamber diameter of Vicky I can probably die cut some foam for you.
 

[cannonmn]

if you can get me the chamber diameter of Vicky I can probably die cut some foam for you.
 

Thanks. It all has to pass down a long 3.6-inch hole so I'm sure a 3.6 in. diameter will go.  If 3.65 or 3.7 in. would go with under saty 30 lb. of force on rammer, that would work too.  As far as I know the chamber is 3.6 in. dia., just without the rifling grooves.

[KABAR2]

I will see what dies we have that are close I know we have a 3.5" die, I will see if there is one a tad larger.