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Tight barrels vs. Loose barrels


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#1 Nerf FNG

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Posted 06 November 2013 - 08:54 PM

Tight barrels vs. Loose barrels. While certain tests can have results favored in either one, here's the facts behind these.

A tight barrel will lead to tight shot grouping and greater range ONLY IF barrel pressure is constantly maintained high and the projectile is a tight fit on the barrel.

A loose barrel, commonly seen in nerf guns, has wide shot grouping, is ineffecient in terms of propulsion of projectiles(i will look further into loose barrels)

Nerf Guns are loose barreled because they cannot(Even without air restrictor, or with your semilethal homemade) have a velocity high enough to get darts to effeciently fly past the tight barrel(see my topic on rifling). Military guns (such as the AR-15/M-16, whose springs are exploited by the hardcore nerf gunsmith) on the other hand, are TIGHT barreled because the bullets they fire can effectively use the advantages of a tight barrel, even with the intense friction inside the barrel when firing.

As always, i will conduct more research on this matter in my free time.

Edited by Nerf FNG, 06 November 2013 - 08:55 PM.

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#2 Doom

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Posted 06 November 2013 - 10:01 PM

Is this just speculation?

Barrel tightness varies greatly among Nerf guns and real guns. In Nerf guns, you want most of the barrel to be loose enough to seal without significant friction. The best initial tightness is controlled by how quickly pressure builds up with a loose segment in the initial stage of the dart's travel. If the pressure is slow to build so that the dart moves down the barrel, further decreasing pressure, then you want a tight section at the beginning to allow pressure to build. That's the case for springers. Air guns usually have faster air releases, so they usually don't need high initial friction.

Adjusting friction can improve muzzle velocity, but the effects it has on accuracy are a lot more indirect. If the dart is so loose that air blows past it, then your accuracy will suffer, but that's undesirably for other reasons too.
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