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
Reloading
FL sizing ?
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="Bill Johnson" data-source="post: 1062613" data-attributes="member: 84129"><p>I see you have another post along these lines. First I would say is that I successfully loaded hundreds of thousands of rounds before ever hearing about or measuring cartridges in this manner, long before the internet or the introduction of tools such as the Hornady cartridge gage. </p><p> </p><p>Firearm chambers have headspace, cartridges do not. Headspace is the distance from the breech face, with locking lugs/mechanism loaded, to the chamber datum for a specific cartridge.</p><p></p><p>It appears that you are using a tool, such as the Hornady tool, to measure from the cartridge head to the datum. While nice to know, it tells you nothing about the chamber except how much it is allows the case head-to-datum line to increase with each firing, and that's dependent on pressure developed in the case as well as case condition (metallurgical properties). </p><p> </p><p>Given your measurements, about all that can be definitely said is that the Winchester brass will end up stretching the most. </p><p> </p><p>As far as the difference between your case measurements and SAAMI chamber specifications, there is no "excessive" amount. In a 30-06 rifle with a good extractor, such as a Mauser or Springfield, a 308 Winchester cartridge can be safely fired and all you will end up with is a straight wall case marked 308!</p><p> </p><p>The difference between your cases and actual chamber dimensions will affect case life. Cases sized or resized to SAAMI minimums, shot in a chamber cut to maximums or even worn beyond will exhibit the shortest case life in high pressure loads. I had this situation when I first started out. An old 30-30 with cases resized in dies set up per RCBS instructions only lasted 4-5 firings before I'd see signs of a imminent case head separation.</p><p> </p><p>That is what your tool is for: Not to determine headspace but to determine how best to set your dies up. For best case life, you want to "bump" the shoulder back (which is where the datum line is on most bottle neck, non-rimmed or belted cases) .002 from what a fired case measures. </p><p> </p><p>The .002 allows minimum clearance to ensure easy chambering while minimizing case growth / maximizing case life. </p><p> </p><p>Whew! JFYI, I usually make about $150 in salary for the time it took to type all this. <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite1" alt=":)" title="Smile :)" loading="lazy" data-shortname=":)" /></p><p> </p><p>P.S. And it's not because I'm that slow a typist!<img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite8" alt=":D" title="Big Grin :D" loading="lazy" data-shortname=":D" /></p></blockquote><p></p>
[QUOTE="Bill Johnson, post: 1062613, member: 84129"] I see you have another post along these lines. First I would say is that I successfully loaded hundreds of thousands of rounds before ever hearing about or measuring cartridges in this manner, long before the internet or the introduction of tools such as the Hornady cartridge gage. Firearm chambers have headspace, cartridges do not. Headspace is the distance from the breech face, with locking lugs/mechanism loaded, to the chamber datum for a specific cartridge. It appears that you are using a tool, such as the Hornady tool, to measure from the cartridge head to the datum. While nice to know, it tells you nothing about the chamber except how much it is allows the case head-to-datum line to increase with each firing, and that's dependent on pressure developed in the case as well as case condition (metallurgical properties). Given your measurements, about all that can be definitely said is that the Winchester brass will end up stretching the most. As far as the difference between your case measurements and SAAMI chamber specifications, there is no "excessive" amount. In a 30-06 rifle with a good extractor, such as a Mauser or Springfield, a 308 Winchester cartridge can be safely fired and all you will end up with is a straight wall case marked 308! The difference between your cases and actual chamber dimensions will affect case life. Cases sized or resized to SAAMI minimums, shot in a chamber cut to maximums or even worn beyond will exhibit the shortest case life in high pressure loads. I had this situation when I first started out. An old 30-30 with cases resized in dies set up per RCBS instructions only lasted 4-5 firings before I'd see signs of a imminent case head separation. That is what your tool is for: Not to determine headspace but to determine how best to set your dies up. For best case life, you want to "bump" the shoulder back (which is where the datum line is on most bottle neck, non-rimmed or belted cases) .002 from what a fired case measures. The .002 allows minimum clearance to ensure easy chambering while minimizing case growth / maximizing case life. Whew! JFYI, I usually make about $150 in salary for the time it took to type all this. :) P.S. And it's not because I'm that slow a typist!:D [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
Rifles, Reloading, Optics, Equipment
Reloading
FL sizing ?
Top