Login    Register
User Information
Username:
Password:
We are a free and open
community, all are welcome.
Click here to Register
Sponsored
Who is online

In total there are 54 users online :: 5 registered, 0 hidden and 49 guests


Most users ever online was 155 on Mon Aug 15, 2016 1:40 am

Registered users: Bing [Bot], Google [Bot], Majestic-12 [Bot], MSNbot Media, Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

ammo length

Post about things you have launched or thought about launching. Also post about various materials used for building cannons. No posts about explosive projectiles!
Sponsored 
  • Author
    Message

ammo length

Unread postAuthor: raptorforce » Sat Dec 20, 2008 4:57 am

does it matter how lng wooden dowels should be. for my gun i use sharpend steel encase in wood in the form of a spitzer bullet. and i was just wondering does it matter how long the projectile should be?
  • 0


raptorforce
Sergeant First Class
Sergeant First Class
 
Posts: 137
Joined: Wed Nov 26, 2008 2:18 am
Reputation: 0

Unread postAuthor: cheeseboy » Sat Dec 20, 2008 5:39 am

Does it matter how long wooden dowels should be. As ammunition for my gun I use sharpened steel encased in wood in the form of a spitzer bullet. I was just wondering whether it matters how long the projectile should be?

there now I can answer your question :D it depends, really a projectile should be as long as possible to allow a less steep surface for air to pass over creating less resistance, but that makes it heavier. For me to give you a precise measurement please give a barrel diameter.
  • 0

User avatar
cheeseboy
Sergeant
Sergeant
 
Posts: 84
Joined: Tue Nov 25, 2008 3:06 am
Reputation: 0

Unread postAuthor: CasinoVanart » Sat Dec 20, 2008 6:30 am

cheeseboy wrote:Does it matter how long wooden dowels should be. As ammunition for my gun I use sharpened steel encased in wood in the form of a spitzer bullet. I was just wondering whether it matters how long the projectile should be?

there now I can answer your question :D it depends, really a projectile should be as long as possible to allow a less steep surface for air to pass over creating less resistance, but that makes it heavier. For me to give you a precise measurement please give a barrel diameter.


How can you say you are going to answer a question :D Then ask for the barrel diameter?

An easy way to obtain projectile length is to simply make the ammo slightly longer than the barrel diameter to stop jamming (in the case of non spherical rounds).

Experiment with different lengths until you get result you were after.
  • 0

User avatar
CasinoVanart
1st Lieutenant
1st Lieutenant
 
Posts: 281
Joined: Wed Jul 30, 2008 1:10 am
Reputation: 0

Unread postAuthor: jackssmirkingrevenge » Sat Dec 20, 2008 6:57 am

Rather than length, what you should be concerned with for stable flight is where the centre of gravity is. As a general rule the projectile should balance at around 25% of its length (measured from the front) which would imply a fairly long wooden tail with a metal tip. If you hollow out the tail, you can get away with shorter lengths while retaining stability.
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

Unread postAuthor: raptorforce » Sat Dec 20, 2008 6:33 pm

cheeseboy wrote:Does it matter how long wooden dowels should be. As ammunition for my gun I use sharpened steel encased in wood in the form of a spitzer bullet. I was just wondering whether it matters how long the projectile should be?

there now I can answer your question :D it depends, really a projectile should be as long as possible to allow a less steep surface for air to pass over creating less resistance, but that makes it heavier. For me to give you a precise measurement please give a barrel diameter.


the diameter would be .75 inches
  • 0


raptorforce
Sergeant First Class
Sergeant First Class
 
Posts: 137
Joined: Wed Nov 26, 2008 2:18 am
Reputation: 0

Unread postAuthor: raptorforce » Sat Dec 20, 2008 6:35 pm

jackssmirkingrevenge wrote:Rather than length, what you should be concerned with for stable flight is where the centre of gravity is. As a general rule the projectile should balance at around 25% of its length (measured from the front) which would imply a fairly long wooden tail with a metal tip. If you hollow out the tail, you can get away with shorter lengths while retaining stability.


If you hollow out the tail then your losing wieght which brings the center of gravity forward more. Then to you my question is what should the length of the projectile be to maintain the a good stable flight
  • 0


raptorforce
Sergeant First Class
Sergeant First Class
 
Posts: 137
Joined: Wed Nov 26, 2008 2:18 am
Reputation: 0

Unread postAuthor: CasinoVanart » Sat Dec 20, 2008 11:11 pm

1.5" at a guess, with a hollow tail of coarse.
  • 0

User avatar
CasinoVanart
1st Lieutenant
1st Lieutenant
 
Posts: 281
Joined: Wed Jul 30, 2008 1:10 am
Reputation: 0

Sponsored

Sponsor
 


Unread postAuthor: raptorforce » Sun Dec 21, 2008 1:41 am

CasinoVanart wrote:1.5" at a guess, with a hollow tail of coarse.


why not 5 inches long and what does a hollow tail do
  • 0


raptorforce
Sergeant First Class
Sergeant First Class
 
Posts: 137
Joined: Wed Nov 26, 2008 2:18 am
Reputation: 0

Unread postAuthor: jackssmirkingrevenge » Sun Dec 21, 2008 2:22 am

raptorforce wrote:If you hollow out the tail then your losing wieght which brings the center of gravity forward more.


That's the whole idea, for stable flight wthout rifling you need a forward centre of gravity, and hollowing out the tail helps to achieve this while keeping a reasonably compact projectile.

All lead foster slugs made for shotguns for example are less than twice the diameter of the barrel and are holowed out to the extent that the projectile resembles a cup.
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

Unread postAuthor: raptorforce » Sun Dec 21, 2008 3:23 am

jackssmirkingrevenge wrote:
raptorforce wrote:If you hollow out the tail then your losing wieght which brings the center of gravity forward more.


That's the whole idea, for stable flight wthout rifling you need a forward centre of gravity, and hollowing out the tail helps to achieve this while keeping a reasonably compact projectile.

All lead foster slugs made for shotguns for example are less than twice the diameter of the barrel and are holowed out to the extent that the projectile resembles a cup.


ok so how long should it be
  • 0


raptorforce
Sergeant First Class
Sergeant First Class
 
Posts: 137
Joined: Wed Nov 26, 2008 2:18 am
Reputation: 0

Unread postAuthor: Gippeto » Sun Dec 21, 2008 12:21 pm

The foster type slugs I make for my co-ax are .758"dia. The light slug (550 grain) is 1" long.

The heavy slug (830 grain) is 1.3" in length.

This translates out to ~1.3:1 and 1.7:1 (length:diameter)

The few that I have fired (550gr), hit straight. Admittedly, as I did not have the scope mounted, the range was short. (10 yards)

As soon as the bloody weather cooperates, I should have longer range data. (-36C this morning, without the windchill )
  • 0

"It could be that the purpose of your life is to serve as a warning to others" – unknown

Liberalism is a mental disorder, reality is it's cure.
User avatar
Gippeto
Donating Member
Donating Member
 
Posts: 2393
Joined: Sat Jan 19, 2008 10:14 am
Location: The Great White North...Canada eh!
Reputation: 11

Unread postAuthor: raptorforce » Sun Dec 21, 2008 4:00 pm

Gippeto wrote:The foster type slugs I make for my co-ax are .758"dia. The light slug (550 grain) is 1" long.

The heavy slug (830 grain) is 1.3" in length.

This translates out to ~1.3:1 and 1.7:1 (length:diameter)

The few that I have fired (550gr), hit straight. Admittedly, as I did not have the scope mounted, the range was short. (10 yards)

As soon as the bloody weather cooperates, I should have longer range data. (-36C this morning, without the windchill )


how do you know that there isnt a better length that you can use
  • 0


raptorforce
Sergeant First Class
Sergeant First Class
 
Posts: 137
Joined: Wed Nov 26, 2008 2:18 am
Reputation: 0

Unread postAuthor: Gippeto » Sun Dec 21, 2008 5:40 pm

Truth be told, I don't know for sure.

I did some research online, and what I found suggested that a slug of 1.7:1 was about the maximum.

What do you know, I found it again. :)

http://www.shotgunworld.com/bbs/viewtop ... e35e5c3000


Aside from that;

The longer the slug is, it either gets heavier, or the wall section gets thinner.

The wall section will be easily deformed/damaged if it gets too thin, so there is a practical limit to how thin I am willing to go.

If the slug gets too heavy, velocity suffers, and with lower velocity slugs, range estimation becomes increasingly important.

This also helped dictate the design.

As things sit, the 550 grain slugs should be ~4.4" high @50 yards, and 4.7" low @100yards. This with an 85 yard zero.

We'll see how they group. :)

I used the ballistics calculators on the Hornady site, info from ggdt, and bc info for a foster slug found online. (bc = .030 - .035)
  • 0

"It could be that the purpose of your life is to serve as a warning to others" – unknown

Liberalism is a mental disorder, reality is it's cure.
User avatar
Gippeto
Donating Member
Donating Member
 
Posts: 2393
Joined: Sat Jan 19, 2008 10:14 am
Location: The Great White North...Canada eh!
Reputation: 11

Return to Construction Materials/Ammo Discussion

Who is online

Registered users: Bing [Bot], Google [Bot], Majestic-12 [Bot], MSNbot Media, Yahoo [Bot]

Reputation System ©'