M
max.burgess
Guest
Can some one tell me what the expansion chamber does & how importen it is in a Break. Do you still need to crown your barrel & break ? Thanks Max
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M
mike in co
Guest
hmmmmmmmmmmmm
another can of worms but
basics...
column of compressed gas behind your bullet as it moves down the bbl.
in std bbl this gas typically is still expanding as the bullet leaves the bbl....pushes the bullet a little, and expands in the air outside the bbl....little affect on the bbl/gun.
the bullet leaves the bbl and enters the expansion chamber...so yes you need a crown.
the chamber is bigger than the bore, and some gas expands to fill the chamber, but is still moving forward. the time it takes the bullet to cross the expansion chamber determines the actual expansion..a pressure drop.
some of the expanded gas, which is mostly moving forward, hit the forward wall of the expansion chamber and exchange momentum into energy...pushing the brake forward...putting the brakes on rearward movement. if there were no side ports the same gas would hit the back of the chamber and counteract to some degree what just happened. heck some emay still but with ports the amount is insignificant.
no more pissing contest past this point.
the bullet with a column of lower pressure gas still has to exit the end of the brake...so the bore of the brake must be parallel to the original bore and have a decent crown.
let the whining begin
mike in co
another can of worms but
basics...
column of compressed gas behind your bullet as it moves down the bbl.
in std bbl this gas typically is still expanding as the bullet leaves the bbl....pushes the bullet a little, and expands in the air outside the bbl....little affect on the bbl/gun.
the bullet leaves the bbl and enters the expansion chamber...so yes you need a crown.
the chamber is bigger than the bore, and some gas expands to fill the chamber, but is still moving forward. the time it takes the bullet to cross the expansion chamber determines the actual expansion..a pressure drop.
some of the expanded gas, which is mostly moving forward, hit the forward wall of the expansion chamber and exchange momentum into energy...pushing the brake forward...putting the brakes on rearward movement. if there were no side ports the same gas would hit the back of the chamber and counteract to some degree what just happened. heck some emay still but with ports the amount is insignificant.
no more pissing contest past this point.
the bullet with a column of lower pressure gas still has to exit the end of the brake...so the bore of the brake must be parallel to the original bore and have a decent crown.
let the whining begin
mike in co
While I don't completely agree with Mike's verbiage (for instance, "....exchange momentum into energy") I think he got the gist of it.
No magic, just put up some sheets of plywood for the wind to slam against, IMO the "expansion chamber" just makes a larger wall for the gas to impact against.
al
No magic, just put up some sheets of plywood for the wind to slam against, IMO the "expansion chamber" just makes a larger wall for the gas to impact against.
al