SpudFiles

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?

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 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.

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 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 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.

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.

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 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

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

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

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

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.

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

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 )

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

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)