Mosin nagant 7.62x54r

[Ro-bert]

Mandrel is during the sizing more or less static in view of cartridge case. The sizing "happens" on the last few milimeters - You push the mandrel with shellholder.

[Ro-bert]

because the "edit" button disappeared - i wrote stupidity above : You push the collet with shellholder / not mandrel

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[Parashooter]

Maybe this cutaway image will help show how mandrel sits inside case neck. Moving collet, forced by shellholder into stationary sleeve, compresses neck onto mandrel.


You can view the entire US patent on the Lee collet neck sizer at Patent Images
(Page doesn't work for me in Firefox but is OK in IE browser.)

[jmoore]

So the mandrel IS inside the case neck controlling the minimum ID. Makes more sense- but one may encounter some variation due to brass hardness in the worked area. Probably not significant for most purposes.


ight try one some time.

[bouletbill]

When I first started reloading .303 with a Lee die set, I could find nothing in the instructions that told me to lube the top of the collet ... but it does say - Quote: 'The neck is sized at the very end of the stroke. It requires considerable force on the press lever.'

So I well leaned onto my old Wamadet, and stripped the thread off the alloy cap on the die top ... just thought it worth mentioning.