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Posted: Tue Oct 27, 2009 7:03 am
by boyntonstu
jor2daje wrote:it pretty easy to make golfballs fit normal sch40 1.5" pvc, here is an instructable on how, it works great, the crappier the ball the better because some of the nicer balls are rubber band balls on the inside.
Yes, that would give you a smooth 1.5" blue sphere.

It would not fly as well as a dimpled golf ball but it would fit the PVC pipe.

My thinking consists of several parts:

Cutting a golf ball to fit a copper or steel barrel for a 550 psi shot.

Imagine if you could stuff it into a barrel like a spud.

Would a slightly 'cylinderedized' dimpled gof ball fly straight and far?

As I recall there is a very expensive ($3,000) .50 smooth bore pneumatic hunying rifle out there that shoots heavy projectiles with amazing accuracy and power.

BoyntonStu

Posted: Tue Oct 27, 2009 7:22 am
by jor2daje
But why botther with golf balls if your going to be doing so much modification? Golf balls are great ammo because they are very uniform, fairly dense, and have low air resistance.

Posted: Tue Oct 27, 2009 7:48 am
by boyntonstu
jor2daje wrote:But why botther with golf balls if your going to be doing so much modification? Golf balls are great ammo because they are very uniform, fairly dense, and have low air resistance.
Yes, I agree, except for getting 550 psi behind them.

How would you do it with a safety margin?

If you could drop a ball into a hopper and out came a custom sized projectile, would that be nice?

Posted: Tue Oct 27, 2009 10:13 am
by psycix
Cutting a projectile is easier then sleeving a barrel.
However, sleeving the barrel is easier then cutting hundreds of projectiles.

It depends on the amount of shots you expect to fire.

Posted: Tue Oct 27, 2009 10:26 am
by boyntonstu
psycix wrote:Cutting a projectile is easier then sleeving a barrel.
However, sleeving the barrel is easier then cutting hundreds of projectiles.

It depends on the amount of shots you expect to fire.
Is a cylindicalized golf ball superior.

What barrel for 550psi?

Posted: Tue Oct 27, 2009 4:06 pm
by psycix
I think a round ball goes further then a "cylindicalized" one, unless it is stabilized.

What barrel?
Something steel or aluminum probably.

Posted: Tue Oct 27, 2009 4:56 pm
by spudtyrrant
psycix wrote:I think a round ball goes further then a "cylindicalized" one, unless it is stabilized.

What barrel?
Something steel or aluminum probably.
i think he's talking about using that copper piston gun he has, sdr 21 sleeved in 2" schedule 80 should work fine for the barrel, also i agree a round ball should travel farther than a "cylinderized" one

Posted: Tue Oct 27, 2009 5:12 pm
by KAOS99
Well, I'm new here, and I see that there are a lot of advanced gunners here. I don't know how close of a fit you want with the GB in the barrel, or what you are trying to hit, but I screwed around with my brother in Canada, and he found a piece of metal (I believe, steel) fence tube, thin-walled, that fit a GB nicely. I mean, it rolled down the barrel, but not sloppily. Seemed to work pretty well.

Posted: Wed Oct 28, 2009 6:10 am
by psycix
sdr 21 sleeved in 2" schedule 80 should work fine for the barrel
Not with PVC and 550 psi...

Posted: Wed Oct 28, 2009 9:51 am
by Moonbogg
1 1/2 SCH10 pipe works well for golf balls. Only a little honing and the balls fit snug, without rolling out. Aluminum is what I use. If you are trying to make golf balls work with a plastic cannon and 500psi I would forget it.

Posted: Wed Oct 28, 2009 10:56 am
by rp181
golf balls have very think shells, the inside is kind of like a rubber band ball, that was heated to stick to the shell. Unless your machining very little, you will find your self with a stretchy ball, with two hard shells at the end.

Posted: Wed Oct 28, 2009 1:44 pm
by psycix
Some even have a liquid core.

Posted: Mon Aug 02, 2010 10:49 am
by Technician1002
A sabot could be used to increase the effective cross section for a powerful shot. I've shot golf balls this way with very good results. Use a low mass sabot.

Use a barrel diameter that matches the performance of your chamber and you can get some pretty good acceleration forces.

The combination below provides over twice the cross sectional area and adds less then 1/3 more mass.
Image

Another sabot that works well; This one is best for low pressure and egg toss distance competition.
Image

Posted: Mon Aug 02, 2010 11:50 am
by Ragnarok
MrCrowley wrote:It'd be interesting if GGDT had a tool for velocity drop of the projectile once it left the barrel, such as detailing the loss in velocity over a certain range.
I really should get back to work on the LRC... :(