Also posted in Varmint rifles.


Ballisticians expertice needed.

What would be the optimum barrel length for a 20cal cartridge on the 221 Fireball case.

I have a 20 VarTarg with a 25 1/4 in barrel and burn 19.2gn 4198 behind a 35gn Berger for 3730fps.
This rifle was built on a XR100 Rem 204 that we shortened the 26in barrel of to rechamber to 20 VarTarg. Get exceptional performance but here in New Zealand we are freely able to have a supressor fitted and which I would like to do but the over all length would be onerous with a barrel left this length. I would like to have it shortened and would apreciate advise as to what length would best give complete powder burn without compromising performance.

Von Gruff.

http://www.loadammo.com/Topics/October05.htm

Read the above, it looks like 30-40 fps per every 2 inch of barrel, for the 375H& and as mush as 80fps for 7mm Rem Mag as you get down around 22-24 cut. the 7mm rem is the only real hi vel round tested, so I would assume more losses with 3700fps loads than shown for the 7mm rem. Just a WAG.

There is no complete, velocity loss gets less and less significant as the barrel increases. And less significant for low velocity ctgs.

Fred Bullberry of Bullberry barrels did some work on this topic. A link is supplied for your pleasure.

204 Ruger Barrel length considerations

Incidently, the above link is also located at the following website.

Home of 204 Ruger

The Effects Of Reducing The Barrel Length On Velocity And Accuracy In The 223 Remington

http://www.accuratereloading.com/223sb.html

In light of this and info recieved on other forums I have decided to go for a 21in barrel. The surpressor will be 4in forward and 8in behind the muzzle so oal will remain the same,

Von Gruff.