The Firing Line Forums - View Single Post - Chamber Pressure in Regards to Cartridge Selection

Saskhunter · November 11, 2012, 07:43 AM

One thing that is missing in the bolt thrust calculations is the friction of the case on the chamber. I have no idea how much of that calculated thrust is "absorbed" by the fact that the case is stuck to the sides of the chamber quite hard during firing, but I would expect it to be a considerable proportion. The only reason you can eject a fired case afterward is the fact that the case springs back a bit after firing and releases itself. It takes a hammer to get a stuck case loose if an over loaded round is fired. That friction absorbs thrust.

November 11, 2012, 07:43 AM	#3
Saskhunter Member Join Date: October 16, 2012 Location: Saskatchewan Posts: 39	One thing that is missing in the bolt thrust calculations is the friction of the case on the chamber. I have no idea how much of that calculated thrust is "absorbed" by the fact that the case is stuck to the sides of the chamber quite hard during firing, but I would expect it to be a considerable proportion. The only reason you can eject a fired case afterward is the fact that the case springs back a bit after firing and releases itself. It takes a hammer to get a stuck case loose if an over loaded round is fired. That friction absorbs thrust.