5 replies to this topic

[canuck]

I have been searching around the forum and I have been wondering how [if it does at all] the length of the barrel affects the accuracy of the dart. I know there are other deciding factors like barrel material, dart, and gun, but being generaly newer to nerf I never realy had the chance to test it. I am not that big an idoit [I'm not denying I am] so don't worry that i wont understand what you are saying.
-Thanks

[Renegademilitia15]

Actually no, dart quality=Accuracy

Barrel Length=range.

( On airguns )

[Doom]

Yes and no.

Barrel length only improve accuracy in two ways. The first is if the barrel is shorter than the projectile, then the projectile could go in any sort of direction. The second is sight radius--the distance between the front and back sights--which is longer with longer barrels and will make your aim more precise and likely more accurate.

Barrel length can and will reduce accuracy in real guns due to vibration. Longer barrels vibrate more easily. We don't have to worry about this in Nerf. However, we do have to worry about the similar problem of the barrel bending under its own weight in materials like PETG which could affect accuracy.

Also, longer barrels don't necessarily increase performance. Make the barrel too long and your performance will decrease due to friction and pressure drop.

Edited by Doom, 22 May 2009 - 10:27 AM.

[nerkum]

There are a couple of factors to a barrel you must take into account.

First would be how much air volume you are going to push into the barrel. A Firefly does not have a large plunger, so it cannot force the expansion of much air into the barrel. So a shorter barrel will allow the dart to catch the most of the expanding air in the barrel before it is expelled out and the rest of the air pressure is lost out the end of the barrel. Match your barrel with your plunger size.

Second thing to consider is how snug your darts will fit in the barrel. If you have a super snug barrel with a long barrel most likely your dart is just going to stick in the barrel when the expanding air cannot overcome the friction of the barrel. That will bring you to nesting your barrel with a snug fit where you place the dart and then a loose fit to stabilize the dart in flight. If you do a short snug barrel with a powerful springer you will notice your dart will sometimes spiral out of control from the dart not able to catch enough of the expanding air before it leaves the barrel.

Last thing you should look at is the friction of your barrel material. If you have a smooth surface you can have a longer barrel, while a rougher surface you will want to shorten your barrel so you do not lose any velocity to friction.

[Zorns Lemma]

Barrel length only improve accuracy in two ways. The first is if the barrel is shorter than the projectile, then the projectile could go in any sort of direction. The second is sight radius--the distance between the front and back sights--which is longer with longer barrels and will make your aim more precise and likely more accurate.

Wouldn't a barrel length optimized for range (i.e. ends where dart stops accelerating) also optimizes accuracy? If the barrel is too short, you would have different pressure levels around the dart and directly behind it, leading to turbulence, which theoretically disrupts accuracy. This doesn't happen when the dart is still in the barrel because friction forces keep the dart on path.

[Doom]

Wouldn't a barrel length optimized for range (i.e. ends where dart stops accelerating) also optimizes accuracy? If the barrel is too short, you would have different pressure levels around the dart and directly behind it, leading to turbulence, which theoretically disrupts accuracy. This doesn't happen when the dart is still in the barrel because friction forces keep the dart on path.

Yes, that should be generally true. That makes sense if the final barrel pressure is near atmospheric pressure. In my experience running simulations, that's not always the case (likely due mostly to dynamic pressure's effect), but it should be generally true and it's definitely something to think about now that you've mentioned it.

As most darts get their stability from their center of gravity being in the nose, some wacky effects on the back likely don't matter as much as they do in real guns, but it could cause some problems.

Edited by Doom, 22 May 2009 - 04:30 PM.