Forums
New posts
Search forums
What's new
Articles
Latest reviews
Author list
Classifieds
Log in
Register
What's new
Search
Search
Search titles and first posts only
Search titles only
By:
New posts
Search forums
Menu
Log in
Register
Install the app
Install
Forums
Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
Defiance AnTi question
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Message
<blockquote data-quote="Fiftydriver" data-source="post: 2741888" data-attributes="member: 10"><p>All modern rifle chamberings are loaded to pressures that permanently deform brass, meaning that even loaded to normal top working pressures, the case will be tight to some degree in the chamber. What your feeling is likely the mechanical cam making contact which mechanically pulls the tight case out of the chamber. All modern receivers have a mechanical cam device to do this, as such, you usually never notice the tightness of the case in the chamber at normal top working pressures. If you do feel resistence, it can be caused by many things, most common to handloaders is excessive pressure or brass that has many firings on it. Brass has elastic properties which means it stretches under a pressure load. Then when the pressure drops, the case will contract slightly allowing us to extract the case.</p><p></p><p>the higher the pressure, the harder the brass is pressed against the chamber walls and the less it will contract. The older the brass, the less elastic properties the brass has as it work hardens from repeated heat and pressure cycles.</p><p></p><p>point being, never try to rechamber a fired unsized case, that in and of itself will not hurt a rifle but if there is any dirt in the chamber of on the case, it can lead to scratched chambers. </p><p>this is also why i never recommend neck sizing only rifle brass. In some limited applications it can work well but for most large big game hunting rifles, its not a good idea. </p><p></p><p>Forcing an unsized case back into your chamber will often cause a tighter fit then it was right after firing as the brass will relax a bit when extracted, especially if brass is older.</p><p></p><p>likely running pressures a bit to high or have older brass.</p><p></p><p>the larger diameter the case, the larger surface area mating to the chamber as well, which will exaggerate this problem. This is why a 223 can be loaded to +75,000 psi and not even be able to tell there are any pressure issues but a 300 rum will get tight around 65,000 psi and a 50 bmg around 55,000 psi. Larger the surface area, more contact area with the chamber making it more difficult for the mechanical cam in the receiver to break the fired case free from the chamber.</p></blockquote><p></p>
[QUOTE="Fiftydriver, post: 2741888, member: 10"] All modern rifle chamberings are loaded to pressures that permanently deform brass, meaning that even loaded to normal top working pressures, the case will be tight to some degree in the chamber. What your feeling is likely the mechanical cam making contact which mechanically pulls the tight case out of the chamber. All modern receivers have a mechanical cam device to do this, as such, you usually never notice the tightness of the case in the chamber at normal top working pressures. If you do feel resistence, it can be caused by many things, most common to handloaders is excessive pressure or brass that has many firings on it. Brass has elastic properties which means it stretches under a pressure load. Then when the pressure drops, the case will contract slightly allowing us to extract the case. the higher the pressure, the harder the brass is pressed against the chamber walls and the less it will contract. The older the brass, the less elastic properties the brass has as it work hardens from repeated heat and pressure cycles. point being, never try to rechamber a fired unsized case, that in and of itself will not hurt a rifle but if there is any dirt in the chamber of on the case, it can lead to scratched chambers. this is also why i never recommend neck sizing only rifle brass. In some limited applications it can work well but for most large big game hunting rifles, its not a good idea. Forcing an unsized case back into your chamber will often cause a tighter fit then it was right after firing as the brass will relax a bit when extracted, especially if brass is older. likely running pressures a bit to high or have older brass. the larger diameter the case, the larger surface area mating to the chamber as well, which will exaggerate this problem. This is why a 223 can be loaded to +75,000 psi and not even be able to tell there are any pressure issues but a 300 rum will get tight around 65,000 psi and a 50 bmg around 55,000 psi. Larger the surface area, more contact area with the chamber making it more difficult for the mechanical cam in the receiver to break the fired case free from the chamber. [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
Defiance AnTi question
Top