Thread: Seating depth measurement problems

Last night I built my own Modified case. I drilled out a primer pocket to fit a cleaning rod, sized the neck of the case and than took to it with my Dramel and cut three cuts down to the shoulder, sized it again to be sure the neck was good.

I can now put my projectile of choice in the case by hand(but still firm). I then insert the case, with projectile to the chamber and gently push the case in with the cleaning rod, then put the rod down the primer pocket hole and insure the projectile is alway the way forward. Gently remove the case(with projectile) and measure the overal length.

I'm consistancely get the same measurement to 0.003".

I've also use the cleaning rod(with a square/flush end) down the bore to the bolt face, mark the rod at the end of the barrel. Then place a projectile gently into the chamber and do the same thing with the rod. Measure between the two marks on the rod and that should be the total overall length. I got a very simalar length with this method and was very repeatable once I got the method fine tuned.

I'll get some photos.

Marks on the bullet CAN be differcult to define sometime.

Check your mag length too!