primer pocket clean up

[johan teughels]

took me a will but i wondered why each time i cleaned my primer pocket it seems the cutter had some fresh meat to grind away . my first idea was that the case head was blowing down fromthe force of the powder . but afer a few reloads brass was difficult to slide in my lee shellholder for priming . i took some cases and measured the dia. from the case head an they measured up to 0.01" bigger then a new case . if the primer pocket was expanding that mutch no way the primer will hold in the pocket but they dit no problem, therewas still good tension on the primers. so the only thing i came up with is that the base is flatening and expanding from the extractor grove down and so every time i cleand up the pocket with my tool i grinds the pocket back to the dept from the tool (tools stops on the casehead for depth)

 

[Al Nyhus]

.....the only thing i came up with is that the base is flatening and expanding from the extractor grove down and so every time i cleand up the pocket with my tool i grinds the pocket back to the dept from the tool (tools stops on the casehead for depth)

Yes, that's basically it.

As a point of interest, I've found that not uniforming the primer pocket before the initial firing (I know...total BR blasphemy ) seems to allow the pocket to 'settle down' quicker...for lack of a better term. Uniforming the pockets after the first firing seems to remove less material and there's less removed during subsequent firings until they take a permanent 'set' and all you remove is carbon.

This is with Lapua cases (220R, 6BR, 223, 22-250, 243 and 308 and 308 Palma). Some Lapua case need a bit of pocket touch up to remove the taper to allow the primer to seat. On those, I just go down to the floor of the pocket and stop.

Good shootin'. -Al