AlanF wrote:Barry,
I had some some misfires recently with tight primers - the reason was they were so tight I couldn't feel when the primer had seated and was pressing them further in until they became somewhat squashed, and too far from the firing pin. If your primers are seating deeper than flush sometimes, then you may be experiencing the same as I did - solution for me was simply to take more care when seating to feel when the primer bottoms (I use a RCBS hand priming tool).
Alan
Good evening, all
'Uniforming' the pockets only deepen them, and probably over what is necessary for a normal setting. Simply removing the radius at bottom is most certainly sufficient to add depth to the pocket.
The primers heights are rather closely toletanced to match the best witht the various brands of cases whose pockets are also intended to match with the various brands of primers.
The anvil must bears against the pocket bottom, and the primer face must NOT be too deep in order to match with the firig pin protrusion, which in turn is set as to ensure ignition of a normally seated primer, which in turn..which in turn...which in turn......
My point is that any modification have consequences, and inconsequently made renders the results even worse.
As for seating depths, there is a small tolerance in the anvil searing. It is not the primer cup who needs to bear against the pocket bottom, it is that anvil, and this is usually best achieved (when every dimension is respected) when the primer bottom is about 0,05mm under the case rear.
If one observes closely a primer, it will be noticed that the anvil protrudes slightly (0,1 to 0,2mm) out of the cup. This is enough to care about the radius at pocket bottom, but still allowing the anvil to bear. If the radius is removed, the seating (up to 'feel) neds to bring the cup too deep, as the 'feel" is then when the case is too deep of the value of the radius. The anvil is then pushed too deep in the cup, the priming compound is crushed (first cause of misfires), and the primer is too deep from the case bottom.
If the primer is insufficiently seated, the anvil is not supported, and gives up on impact (second cause of misfires).
Over-seating, this is to say up to the primer cup bears against the pocket bottom tends to overseat the anvil, thus crushing the priming compound and disintegrating it. This is a common case with certain prmers, and the CCI are quite prone to this. But, when seated properly, they are excellent primers.
I thnk measurement are essential. I think I have somewhere the drawings dimensions of the primers height and pockets depths.
R.G.C
R.G.C.
f class shooters, i have been using cci large rifle primers in my lapua cases.they are very hard to push in by the lee hand tool and by my lyman press.when i do get them seated and go to the range one or two do not firer or have to be hit twice,no good when shooting comp. but also when using rem 91/2 large primers wont fit lapua cases,but rem will go into rem cases easly, but shoot larger groups with the same loads. cci shoot tighter groups with the same loads 
. i diffently need help here. any 
i was told to try cci m large primers for my 308 rifle.
)....I got 100 from another batch and they were fine. Once I knew those were ok, I bought 1000 of them.
on the mat. my primer sockets are cleaned out after every shoot.the lapua cases are all old ones,but the cci and rem primers are still hard to push in.
simon c, should i soak my bolt in petrol to see if that is the case with the spring and firing pin,to see if there is any dirt in there 
what do you think of that. please reply. from barry t
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