[Chum]

This is strange

I found this article. The chart seems to say that 16" and 24" is the best length but then they suggest 20" I dont understand. It also states that 16" is the minimum legal length.

http://www.tnssa.org/bblvsvel.htm

 

[Chum]

Yes but did you notice on the velocity charts that the "sweet spot" velocity changes for different ammo and there is 2 different spots. The first "sweet spot is around 15"-16" then again at 24". Its like the bullet slows down then speeds back up again at 24". But this only applies to the .22lr ammo listed. If I am reading this correctly. I wish I could find a similar chart for .22 magnum speed ammo.

http://www.tnssa.org/bblvsvel.htm

 

[Chum]

Clayshooter

Where did you get the .17 info that goes to 24"? I have looked at Bullberry's page and they have data up to 22". And what you said is correct about 16" being the length of highest velocity of the .22lr. It does vary a bit depending on ammo. But if the charts I have looked at are correct the bullet slows after 16" but accelerates back up to very close the same velocity at 24". It's like a double burn rate. I have no clue on what this does for shotguns but the longer barrel defintly helps for sighting. The thing we are trying to plot out is the .22 magnum loads in particular. I can't find any charts that are .22 magnum specific. The .17 is different than the .22lr being optimum at 18-19" so I would have to say the magnum could also be.

The "crack" of a gunshot is the bullet breaking the sound barrier as you said. There are airguns that will do this nowadays. Is that a word? Whether the bullet does it inside or outside the barrel plays a major role in noise level and accuracy. Thats one reason for different velocities of .22lr ammo and one of the main reason for barrels being longer then 16" It gives the bullet time to recover from the effects of breaking the sound barrier. You don't want the loud crack when shooting a .22lr because that means the bullet broke the barrier outside the barrel. Very interesting stuff. If you look up a few posts you will see where I posted a link to a website that has a chart down the page. There is tons of other info.

 

[Chum]

Clay

Thats the way I understand it by looking at those charts but the more I read about it the more I don't think it's correct. It seems to be the rule that .22 get a full burn at 16" The chart has alot of blank spots at 24" But the ones that are listed are in bold type. I guess I was invisioning a ca-boom theory. I'm going to have to pick up a good book on this.