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
Gunsmithing
headspace
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="entoptics" data-source="post: 2312976" data-attributes="member: 104268"><p><a href="https://saami.org/wp-content/uploads/2019/02/ANSI-SAAMI-Z299.4-CFR-Approved-2015-12-14-Posting-Copy.pdf" target="_blank">https://saami.org/wp-content/uploads/2019/02/ANSI-SAAMI-Z299.4-CFR-Approved-2015-12-14-Posting-Copy.pdf</a></p><p><a href="https://saami.org/wp-content/uploads/2019/02/ANSI-SAAMI-Z299.4-CFR-Approved-2015-12-14-Posting-Copy.pdf" target="_blank">Click Here for a link to a PDF with all the current SAAMI drawings...</a></p><p></p><p>Here's 243 WSSM</p><p>[ATTACH=full]304747[/ATTACH]</p><p>As [USER=24284]@shortgrass[/USER] and I (and others) mentioned, unfired brass isn't all that helpful in headspace calculations, other than to get an idea of how hard the first firing might be on the brass. All subsequent firings should be bumped 0.002" back anyway from <em>your chamber dimension</em>, so it's only the initial growth that maters for head separation potential if you're doing things right.</p><p></p><p>For 243 WSSM, a "shortest" scenario is minimum chamber headspace @ 1.2403" and maximum brass size of 1.2434", which would result in a 0.003" crush on the brass (i.e. might not even chamber).</p><p></p><p>The "longest" scenario is 1.2503" + 0.015 Tolerance for a total headspace of 1.2653" headspace and a minimum brass size of 1.2434" - 0.007" or 1.2364" brass. This will result in 0.0289" of brass growth on firing.</p><p></p><p>In my experience, brass makers NEVER make their stuff near max, and usually near minimum or less. So, with a properly setup rifle using Go and No-Go gauges, the headspace would be a little above minimum, say 0.004" (1.2443), to accommodate the worst case scenario maximum length brass (1.2434"). Take a piece of minimum SAAMI length brass (1.2364") and fire it in that perfectly head spaced chamber, and she'll grow 0.007".</p><p></p><p>Even if the OP's new brass started at Maximum SAAMI length (unlikely), then grew 0.008" on firing, the chamber would still be at or below the SAAMI max allowed.</p></blockquote><p></p>
[QUOTE="entoptics, post: 2312976, member: 104268"] [URL='https://saami.org/wp-content/uploads/2019/02/ANSI-SAAMI-Z299.4-CFR-Approved-2015-12-14-Posting-Copy.pdf'][/URL] [URL='https://saami.org/wp-content/uploads/2019/02/ANSI-SAAMI-Z299.4-CFR-Approved-2015-12-14-Posting-Copy.pdf']Click Here for a link to a PDF with all the current SAAMI drawings...[/URL] Here's 243 WSSM [ATTACH type="full"]304747[/ATTACH] As [USER=24284]@shortgrass[/USER] and I (and others) mentioned, unfired brass isn't all that helpful in headspace calculations, other than to get an idea of how hard the first firing might be on the brass. All subsequent firings should be bumped 0.002" back anyway from [I]your chamber dimension[/I], so it's only the initial growth that maters for head separation potential if you're doing things right. For 243 WSSM, a "shortest" scenario is minimum chamber headspace @ 1.2403" and maximum brass size of 1.2434", which would result in a 0.003" crush on the brass (i.e. might not even chamber). The "longest" scenario is 1.2503" + 0.015 Tolerance for a total headspace of 1.2653" headspace and a minimum brass size of 1.2434" - 0.007" or 1.2364" brass. This will result in 0.0289" of brass growth on firing. In my experience, brass makers NEVER make their stuff near max, and usually near minimum or less. So, with a properly setup rifle using Go and No-Go gauges, the headspace would be a little above minimum, say 0.004" (1.2443), to accommodate the worst case scenario maximum length brass (1.2434"). Take a piece of minimum SAAMI length brass (1.2364") and fire it in that perfectly head spaced chamber, and she'll grow 0.007". Even if the OP's new brass started at Maximum SAAMI length (unlikely), then grew 0.008" on firing, the chamber would still be at or below the SAAMI max allowed. [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
Rifles, Reloading, Optics, Equipment
Gunsmithing
headspace
Top