G.B. cannon accuracy help

[too phister]

Ive got a golf ball cannon with 8" barrel lenth, The Bore is 1.68 so a golf ball hammers in. It launches balls about 800fps, cronyed. Any how They go so fast I or any body elce can see them. When shootin long distace over a lake you can tell the balls are hooking, slicing and curving all oner the place. Has any one rifeled a barrel for golf balls with any accurcy sucess.? Havnt made a for it yet just hand holding it. Till I can get any accuracy  seems pointless. Primers are easyer to find than cannon fuse so I put a primer pocket, hammer and trigger on it. Shot skeet one afternoon Got 3 out of 10 useing about 2oz. of BBs.  Accurcy Help

[Double D]

Ive got a golf ball cannon with 8" barrel lenth, The Bore is 1.68 so a golf ball hammers in. It launches balls about 800fps, cronyed. Any how They go so fast I or any body elce can see them. When shootin long distace over a lake you can tell the balls are hooking, slicing and curving all oner the place. Has any one rifeled a barrel for golf balls with any accurcy sucess.? Havnt made a for it yet just hand holding it. Till I can get any accuracy  seems pointless. Primers are easyer to find than cannon fuse so I put a primer pocket, hammer and trigger on it. Shot skeet one afternoon Got 3 out of 10 useing about 2oz. of BBs.  Accurcy Help

Sounds like you need to start over...if you have drive the golf balls down the bores with a hammer, then to start with you bore is to tight.  I you need windage so the ball goes in without excessive force.  There is a rule of thumb for windage in cannon of 1/40 of bore diameter.  So you need a bore diameter of about 1.73 

Even then it is unlikely you will ever get any thing near accuracy shooting golf balls.  You will need either steel or Zinc  golf ball diameter projectiles..  You will find group buy steel and zinc golf balls listed on the cannon classified board. 

Why don't you tell ius something about how your cannon is made and we can help you get on track.  87 inches iprett short for a cannon barrel in golf ball diameter.

[flagman1776]

 

[Cat Whisperer]

Agree wtih flagman.  Ream the bore.  Often you'll find if you lower the velocity that there is a point where you'll gain accuracy.

[Soot]

The dimples in golf balls there to add distance to the golf shot but make the ball hook and slice.
I'm sure the velocity achieved by a cannon just magnifies the effect.
They make golf balls now without dimples for more accurate shot placement in golf, but they are very expensive.

[Double D]

Long day yesterday...you want the ball to load without excessive force. 

[44magman]

I know this will cause alarm to most, but I have seen a golf ball ONLY cannon that had a slight "bump in the top of the bore,at the muzzle, and a ground out section at the bottom of the bore( so that the ball was able to pass this section at the muzzle without being tight, just a slight downward movement) Just look at a paint ball gun barrell that is used for long distance shooting. This caused the ball to turn top backward as it leaves the bore...aka back spin. This causes the magnus effect and the ball mostly goes straight out of the bore. It dips down for the first 75 feet and then starts climbing. accuracy was 4 hits out of 4 on a 4 foot target at 100 yards.


I do not wish to start an argument, I do not endorse this method, I am just sharing what a friend made and is enjoying shooting. The results speak for them selves. USE extreme caution if you try this method. I know bore obstructions are a big cause for concern.

[The Jeff]

I know this will cause alarm to most, but I have seen a golf ball ONLY cannon that had a slight "bump in the top of the bore,at the muzzle, and a ground out section at the bottom of the bore( so that the ball was able to pass this section at the muzzle without being tight, just a slight downward movement) Just look at a paint ball gun barrell that is used for long distance shooting. This caused the ball to turn top backward as it leaves the bore...aka back spin. This causes the magnus effect and the ball mostly goes straight out of the bore. It dips down for the first 75 feet and then starts climbing. accuracy was 4 hits out of 4 on a 4 foot target at 100 yards.


I do not wish to start an argument, I do not endorse this method, I am just sharing what a friend made and is enjoying shooting. The results speak for them selves. USE extreme caution if you try this method. I know bore obstructions are a big cause for concern.

I once did something similar by attaching 3 rake tines with a hose clamp to the top side of a golfball bored spud gun. They drooped down over the muzzle and when the ball came out of the barrel it would hit the rake tines which would put back spin on it. Like you said, the balls would drop for a while, then start climbing. I had pretty good luck with them going fairly straight.

[Double D]

The effect of spin on a golf balland how to create it has been cussed and discussed here a number of times.  It appears from these discussions that the golf ball just doesn't have enough mass to be an effective projectile at cannon velocities.  As a mortar projectile at lower velocities the golf ball works quite well.

If I had a golf ball caliber cannon, I would not waste my time shooting golf balls from it.  I would use Steel golf balls from Fox Industries or Zinc golf balls form Rotometals

[too phister]

OK That helps. So what i think i understand is since my bore is tight (to use all the energy) the ball is randomly spinning. If my bore wher biger, spin would not be induced (as severly), but to get accuracy the ball should be spinning the exact same every shot. If I could uniformly "roughen" the top of the bore as to make the ball "roll" out the barrel I may be able to keep the tight bore for velocity sake and gain accuracy. This thing is 400 series stainless just under 3" at the muzzle.

[Zulu]

I think you're making a mistake to alter your bore.  Instead, alter the projectile as Double D suggested.
Zulu

[Double D]

OK That helps. So what i think i understand is since my bore is tight (to use all the energy) the ball is randomly spinning. If my bore wher biger, spin would not be induced (as severly), but to get accuracy the ball should be spinning the exact same every shot. If I could uniformly "roughen" the top of the bore as to make the ball "roll" out the barrel I may be able to keep the tight bore for velocity sake and gain accuracy. This thing is 400 series stainless just under 3" at the muzzle.

You have a projectile who's mass isn't capable of benefiting from all the energy generated.   If you had a snug but slip fit and a reduced load you would probably get greater accuracy and more range.

Can't comment on the suitability of 400 range stainless for cannon barrels, I let some one else.

[Double D]

I think you're making a mistake to alter your bore.  Instead, alter the projectile as Double D suggested.
Zulu

He does need to alter the bore to use the other projectiles- ream the bore to 1.72

[too phister]

double d, my intent with this canon barrel is to amuse myself and friends with a cheap ammo. It dose this now. I would like to make it shoot golf balls accuratly. I dont want to decrease velocity, I want to "think outside the box" .what if I make a knurling tool to cut /raise horizontal lines 1/4" wide line down the length of the top of the bore? a friction drive to spin the ball. I'm new to this forum stuff. How do you look for somthing that specific on this forum? as far as beeing an efective wepon, I want to shoot gophers @ 50 yards to start. a golf ball is what i want to use. Got plent of other guns to shoot gophers with but not this one yet. Got a lathe and a bridg-p type mill. can try quite a bit. i like accuracy, its our friend.

[Double D]

double d, my intent with this canon barrel is to amuse myself and friends with a cheap ammo. It dose this now. I would like to make it shoot golf balls accuratly. I dont want to decrease velocity, I want to "think outside the box" .what if I make a knurling tool to cut /raise horizontal lines 1/4" wide line down the length of the top of the bore? a friction drive to spin the ball. I'm new to this forum stuff. How do you look for somthing that specific on this forum? as far as beeing an efective wepon, I want to shoot gophers @ 50 yards to start. a golf ball is what i want to use. Got plent of other guns to shoot gophers with but not this one yet. Got a lathe and a bridg-p type mill. can try quite a bit. i like accuracy, its our friend.

Certainly think out side the box.  Go ahead and try your idea and let us know it works. 

Use the search function at the top of the board to look for specific subjects.

I do not think your idea about  cutting horizontal lines down the top of the bores is a good one.  Those lines will tear you cartridge apart during loading and could harbor sparks after firing.

Also I think, because of inertia, all they  will do is tear the cover off the balls. 

As far as accuracy  for gopher shooting, I shoot some where between 2000 and 5000 rounds or more a year at  Montana gophers and know what it takes to hit one. Some I shoot as far away a 75 yards...

While I wouldn't say you can't hit one with a golf ball, it sure wouldn't be easy.  In Montana it wouldn't be illegal to shoot a gopher with a golf ball cannon, it might be elsewhere. Since you have now publically posted your intent, you better make sure it is legal before you go any further  Either way it isn't really with in the scope of this forum.  If I were to try this I would start by slowing the golf ball down to velocities where the ball is stable and go for it.

I can tell you this I would not waste my time shooting gophers with golf balls, it would get the zinc or steel balls...you do understand that you  shoot them and go pick them up and shoot them again and again.

 Now if you are interested in hearing from us how you can go about doing this we are most glad to share our idea's.

[Cat Whisperer]

double d, my intent with this canon barrel is to amuse myself and friends with a cheap ammo. It dose this now. I would like to make it shoot golf balls accuratly. I dont want to decrease velocity, I want to "think outside the box" .what if I make a knurling tool to cut /raise horizontal lines 1/4" wide line down the length of the top of the bore? a friction drive to spin the ball. I'm new to this forum stuff. How do you look for somthing that specific on this forum? as far as beeing an efective wepon, I want to shoot gophers @ 50 yards to start. a golf ball is what i want to use. Got plent of other guns to shoot gophers with but not this one yet. Got a lathe and a bridg-p type mill. can try quite a bit. i like accuracy, its our friend.

Drive on!
I want to see the video!

I would be tempted to drill and thread a hole on the top of the bore that an adjustable screw could be used to JUST touch the top of the golf ball as it came whizzing down the bore.  Strength of the bore is a consideration, so I'd come back an inch from the muzzle.  400 series stainless is good stuff - using golf balls the pressures are low compared to denser projos.

[keith44]

Ok, here's how I see this:
 
Golfball smoothbore cannon, bored too tightly.  The lack of windage causes the ball to be compressed and elongated during loading (perhaps only slightly) then the bump from ignition compresses the ball in yet another direction.  When the ball finally exits the barrel (bore if you wish) it immediately springs back to its original shape and dimentions (or at least tries to) this also releases energy, most likely in an inconsistant manner.  Since the ball weighs so little this energy pushes it off course, since the energy is not being controlled in any manner, the direction and force of the push is causing most of the accuracy problems.