Author Topic: Windage (Read 1337 times)

Monk · « **on:** February 02, 2006, 04:47:38 PM »

OK I have been reading the posts here for a long time, I know the "Windage rule"The rules seem to change for cannons under 2" bore, so can anyone tell me why I can't load my 1-1/2" bore cannon the same way I do my muzzle loading rifle---IE patched round ball
~Monk~

CU_Cannon · « **Reply #1 on:** February 02, 2006, 05:07:52 PM »

IÂ’m not sure that I would patch anything much over 50 cal. Even at 1.5Â” the pressure can get extremely high. The windage is a bit of a buffer. It accounts for fouling and irregularities in projectiles. Patched balls have the potential to be more accurate. They can however be a pita if they get stuck half way in when loading. Things get really exciting when they get stuck half way out! I donÂ’t feel that the advantages of patching are worth the extra danger.

Monk · « **Reply #2 on:** February 02, 2006, 05:16:38 PM »

The same goes for a rifled cannon, if the projectile doesn't engage the rifling what's the point? I'm not trying to start a war here and I definatly dont want to blow myself up but it seems to me the main reason for windage in the"old days"was probably out of round cannon balls,
~Monk~

Cannonmaker · « **Reply #3 on:** February 02, 2006, 05:23:01 PM »

Monk, in the olden days on the rifled guns they had a Brass ring behind the projectile that would expand into the riflings and give the projectile its twist.

Artilleryman · « **Reply #4 on:** February 02, 2006, 06:05:32 PM »

Gibbon's manual: "Windage diminishes the accuracy of fire, weakens the effect of the charge by allowing an escape of gas, and is the principal cause of deterioration in cannon. It is therefore of importance to make the windage as small as possible compatible with ease and efficiency in loading." The projectile (ball) bounces in the bore on its way out. The more windage the more pronouced this becomes. This will eventually put dents in the bore. They used to change the length of the sabot to prolong the life of the gun.

It is best to have a length of tubing that at least 3 calibers long that has the same bore size as you gun. If you use a liner in your gun a section of that is best. The projectiles that you use should roll freely through this "bore gage". Make sure that the projectile rolls through not slides through. In rifled guns slide through is the only way it is going to work anyway. You can run a fairly close windage as long as the ball will roll through you gage. If you run a tight windage you can run a lighter charge.

If you are casting your projectiles an uneven density or air pockets will have a greater effect on you accuracy than just about anything else. You accuracy will be effected by the way that you swab your bore.

I would never patch a ball because of the possibility of it getting hung up part of the way down. Another reason not to use a patch is that it can start grass fires. Also, if for some reason you can't get the charge to go off you can depress the muzzle and the ball should roll out, and then you can soak the charge and worm it out. If you are using a saboted ball you may not be able to get it to slide out by depressing the muzzle.

As to the balls being out of round in the "olden days" they only allowed .004" between minimum and maximum diameters. They tumbled the balls in a drum with grit to smooth them and round them.

I hope this of some help in making a decision about patching or not.

Cat Whisperer · « **Reply #5 on:** February 03, 2006, 01:15:06 AM »

Quote from: Monk

The same goes for a rifled cannon, if the projectile doesn't engage the rifling what's the point? I'm not trying to start a war here and I definatly dont want to blow myself up but it seems to me the main reason for windage in the"old days"was probably out of round cannon balls,
~Monk~

Raising the question is natural and you've got the right perspective in life on not wanting to blow yourself up!

Having seen the effect of too much patch (40 years or so ago) - a blank load with a lot of newspaper packing - and seeing the cannon explode, I have a high respect (now) for how fast the pressure rises.

I think also that unless you take the trouble to ream and perhaps hone the barrel that the potential for danger is much greater than with a musket that has a very smooth bore.

guardsgunner · « **Reply #6 on:** February 03, 2006, 08:19:47 AM »

You Might go to http://civilwarartillery.com/
and look in the section on feild artillery / rifled. You will find that nearly all the projectiles have something which expands into the rifling, wheter it be a ring moving forward or paper mache'(?) or a cup on the back. Even a minie ball design has windage and relies on expanding into the rifling.

Will Bison · « **Reply #7 on:** February 03, 2006, 08:31:38 AM »

I always use a patch and for good reason. Some 18 or 20 years ago while shooting with a friend, we noted that the ball had rolled forward in the bore some two inches. I attributed this to two things, the twist of the rifling and movement of the gun while aiming.

After some experimenting we noted that as the ball was introduced, it would naturally fall into a groove and follow it. As it followed the twist it would eventually fall over a land an into the next groove. As it did this it would also roll forward in the bore.

Obviously, with enough muzzle elevation the ball would roll back or stay back of its own accord. We also loaded a ball in my friends smooth bore gun. With the muzzle at zero degrees elevation we could get the ball to roll forward just from the normal disturbance of sighting the gun.

Further testing showed that the smooth gun if elevated more than about one or two degrees was OK. The rifled gun required at least five degrees up elevation to prevent the ball from rolling forward.

How to solve the problem and yet maintain some windage? A sabot would work but requires some extra effort to make and fasten to the ball. We opted for a thin patch. Some simple math showed that we could use a patch to offer a slight bit of resistance and still have some windage. All of the cannon shooters in my area now use a patch. When the patched ball is inserted, it can be easily pushed in the bore with the tip of an index finger.

One other factor that may not apply to all shooters is shooting at a down hill target. Most of the places I shoot dictate that targets be placed according to the lay of the land. It's a rare day that we shoot on a level area.

In summary, I'll take my chances with a patch over an air gap between ball and charge.

Bill

Monk · « **Reply #8 on:** February 03, 2006, 09:43:45 AM »

Thanks for all the reply's, My main BP experience is with muzzle loading rifles, and I basicly if you can seat the ball against the charge your OK no matter how tight it was, I cant imagine the trouble it would be to seat a tight cannon ball in a badly fouled barrel, but on board ships at sea they must have done something to hold the balls in place against the charge, after all a vessel rolling from side to side would have had big trouble otherwise.
I plan on shooting lead balls or slugs and am considering making a mold to cast a hollow based bullet so the "skirt" can seal against the wall which are very smooth now they have been honed, compared to a muzzle loading rifle my cannon is "over built".
Thanks again guys, the info available here is mind boggling, you have to love the internet! I don't mind following rules if there is a reason,and I don't want to make anyone mad but all to often noone can tell you why, you just get told "It's the Rules"
~Monk~

Artilleryman · « **Reply #9 on:** February 04, 2006, 12:18:24 PM »

Quote

on board ships at sea they must have done something to hold the balls in place against the charge, after all a vessel rolling from side to side would have had big trouble otherwise.

They either fastened a wad to the ball or rammed a wad down on top the ball. Gibbon's book describes different types of wads. Today since we are not using our guns for combat we try to minimize breech pressure and avoid wads.

Squire Robin · « **Reply #10 on:** February 04, 2006, 12:27:17 PM »

If you shoot a lead ball does windage really matter? An out of round iron ball can really jam up the works if it turns to a wider axis, but lead can deform and save the day.

A tight patch certainly can get the pressures up. When we tried my wall piece with ball it was very gentle on the shoulder even with the 275 gns service charge. The we double patched it and she started to buck a bit, well, a lot actually :-D

That's was a .91" lead ball in a .96" barrel, the barrel wall at the breech being slightly under 0.6" thick. I over cooked the windage and regretted it, wish I'd bought a bigger mould :cry:

Artilleryman · « **Reply #11 on:** February 04, 2006, 05:22:49 PM »

Quote

If you shoot a lead ball does windage really matter? An out of round iron ball can really jam up the works if it turns to a wider axis, but lead can deform and save the day.

With the larger guns lead becomes too heavy, and we use zinc instead. That is way it is important to have a bore gauge to check the projectile for out of roundness if you are running with very little windage. It really sets my teeth on edge when I see a gun crew trying to bang a round home that is hung up in the bore.

GGaskill · « **Reply #12 on:** February 04, 2006, 06:48:46 PM »

It really sets my teeth on edge when I see a gun crew trying to bang a round home that is hung up in the bore.

Doesn't the range safety officer weigh in these events?

guardsgunner · « **Reply #13 on:** February 05, 2006, 12:49:13 AM »

Artillerman, I agree with you that the windage is is very important in any knid of muzzle loader. Even with muskets a lead projectile can virtually
lock in place requiring a hammer to finish forceing the ball home. Those guys 150 years used this stuff everyday and set the rules of thumb that way from experince and not guess work. They had eqp. for testing pressures and tested the materials they had at hand to their limits. Load charts for artillery as well as small arms were set there because that was what work best not because it gave acceptable accuracy or should work ok.

Bob