Re: Tightening Primer Pockets?
I will give a try at what I think the RCBs swage tool is doing to the primer pocket but its open to discussion. If you do a search “ RCBS swage tool to tighten primer pockets” you will see that others do this and it has been discussed a bit.
First off if the rim diameter on a .308 is .408 its doubtful it can be restored. The cases I work with have no sigh of major gas leak. When the RCBS tool is used to remove crimp from military cases the spud on the ram is larger than the pocket, when pushed into the primer pocket it removes the crimp, supported by the rod inside the case.
When the RCBS tool is used to tighten the pocket, the case ( pocket) freely goes over the spud ( dia .205 )on the ram with no resistance. Raise the ram so that there the case is against the support rod in side and the spud, set resistance to feel a firm squeeze, some time I pump it twice. When the ram is lowered the lower sleeve pops the case off the spud and I do mean the pocket is grabbing the spud it is stuck on the spud, where before the case pocket slid on the spud with no resistance ( it is smaller).You can get them too tight small to take a primer.
I think the spud is pushing up on a slightly shallow primer pocket pushing it up to the ram drawing the pocket dia. in a little. In any event when the diameter of the pocket is measured it is smaller. After several times doing this to a case ( I anneal cases after every fifth firing and swage the pockets) there might be some work harding of the pocket ( a good thing). All this is open for your discussion it is just what I think is going on.
So far I have never had a case separation of major event, I have one .308 rifle on its 7th
barrel, yes it has some etching around the firing pin but no big deal, could be polished out. I use Large Magnum Russian primers ( hard brass cup larger dia) if a case does noy feel right when priming into the trash, if its tight going into the shell holder, into the trash.