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Small bore vs. big bore - bullet performance

Post about things you have launched or thought about launching. Also post about various materials used for building cannons. No posts about explosive projectiles!
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Unread postAuthor: POLAND_SPUD » Tue Mar 23, 2010 9:28 am

you know you should dowload chairgun pro... it's a really great programme and you can use it to compare up to 4 different projecitles all at the same time..

but you'd have to find a way to predict the cd value of the darts
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Unread postAuthor: FighterAce » Tue Mar 23, 2010 10:12 am

dewey-1 wrote:This posting shows some dart ideas.
Ready made ones by Ramset or Remington.

http://www.spudfiles.com/forums/nail-da ... 19586.html

Have a look here for center of pressure calculations;

http://www.spudfiles.com/forums/unstabi ... 19849.html


I checked your links but I dont see a working high accuracy bullet design. Its all talk and no action. Hasnt anyone made high accuracy ammo before?
I'd like to see a working design but so far it seems to me nobody ever tried it... not on a larger scale anyways. Most people I know make one dart, shoot it and say they fly straight and accurate. Do it my way and shoot at least 3 darts side by side at the same target and then we'll see if they fly accurately.

POLAND_SPUD wrote:you know you should dowload chairgun pro... it's a really great programme and you can use it to compare up to 4 different projecitles all at the same time..

but you'd have to find a way to predict the cd value of the darts


I'm more of a trial and error type of guy. I'd rather spend quality time making bullets and seeing what works and what doesnt then spending hours in front of the computer and then to find out that it doesnt work after I make the prototype.
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Unread postAuthor: dewey-1 » Tue Mar 23, 2010 10:35 am

[quote="FighterAce
I checked your links but I dont see a working high accuracy bullet design.
I'd like to see a working design but so far it seems to me nobody ever tried it... not on a larger scale anyways. Most people I know make one dart, shoot it and say they fly straight and accurate. Do it my way and shoot at least 3 darts side by side at the same target and then we'll see if they fly accurately.

I'm more of a trial and error type of guy. I'd rather spend quality time making bullets and seeing what works and what doesnt then spending hours in front of the computer and then to find out that it doesnt work after I make the prototype.[/quote]

Well what do you want? Bullets or darts? You start with darts now you are talking bullets. Make up my mnd. :D

The Ramset nails have been used before. Re-read the posting for some results. Just giving iyou deas compared to flimsy paper cone drag stabilization.

I could give you precise 3D/2D drawings that will function but that does not necessarily mean you can machine or fabricate them.

If you have doubts then stick to air gun pellets!
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Unread postAuthor: FighterAce » Tue Mar 23, 2010 1:58 pm

Sorry I used the wrong word there :D Replace the paper with fins, add a bullet shape cone... so many modifications I dont even know how to call them anymore :D

I really dont like using sabots, they can be a hazard to someone standing by and not to mention they are a pain to make fast in large numbers.
I have great doubts about the dart design since I've been using caveman simple, nose heavy darts and all these new designs are pretty alien to me.

What kinds of drawings are you talking about specifically? I know I might not be able to make them but at least I can try or modify them so they are within my reach.

btw. I dont have a commercial air gun and I dont plan on buying one at all. If I'm ever gonna buy a gun its gonna be anything but air powered.
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Unread postAuthor: jackssmirkingrevenge » Tue Mar 23, 2010 2:26 pm

If it's accuracy you want then airgun pellets are a good option if you can obtain them easily. The "diablo" shape keeps it stable in flight even without rifling, they're consistent and with a healthy ballistic coefficient.
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Unread postAuthor: dewey-1 » Tue Mar 23, 2010 2:32 pm

I was referring to pellets as ammo, I did not mention using or buying an air rifle/pistol.

Make your projectile similar to a pellet. Scaled in size to your launchers bore.

If your concerned about sabots around people, maybe they should be behind the shooter some distance away!

Not many choices for projectiles with fins with out a sabot/wadding.
Collapsible/retractable fins is a possibility.

More than likely you will still need some wadding for a good pressure seal unless you use o-rings to seal projectile like:

http://www.spudfiles.com/forums/compoun ... 18485.html
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