Re: What happened to my case head??
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: red hawk</div><div class="ubbcode-body">loose primer pockets... </div></div>
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jeffm</div><div class="ubbcode-body"> Red hawk nailed it, Loose primer pockets.</div></div>
^^No way...
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 1lnbrdg</div><div class="ubbcode-body">The low pressure didn't allow the primer to seal. No seal ment blow-by started which looks like that.</div></div>
Ding ding! Winner!
The slight interference fit (on the order of .001") of a tight-fitting primer in a primer pocket does NOT generate a seal that can handle 50,000+ psi. Rather, chamber pressure blows the primer cup outward, sealing it to the walls of the primer pocket, much the same way as chamber pressure blows the caseneck outward, creating a seal between the case and the chamber.