who knows . there was a reason for them to change it or they would not have done so .
Can the star bit come off and the barrel pressed out? could it be for changing barrels in the way that they may have loads of barrels with breech blocks fitted then they could change them when a customer wants say a .20 and they wont have say 1000 .177, 1000 .20 , 1000.22 and 1000.25 barrels in breech blocks sitting?
iF an order came in for 250 .25 rifles they can press .25 barrels into a breech block and tighten the star Nut .
Basically they make up the barrel and breech block to suit an order rather have them sitting and maybe not moving for months.
Has any one asked why they changed it ?
One of the people in this thread says its a nut https://www.gatewaytoairguns.org/GTA...topic=122796.0