rcbs case mic and bullet seating gauge

[Pwhite11798]

Baught a rcbs head space and bullet seating gauge when i compared its reading to what i was getting using a cut case and jaming a bullet into the chamber was a difference of .030. My question is does the ojive of a bullet change where the bullet touches the lands compared to the rcbs gauge ojive.

 

[GrocMax]

The diameter of the straight bullet hole in the RCBS tool, the ojive of the tool compared to the loaded bullet, and your leade angle add up to the inconsistencies. If the RCBS tool had your exact bullet ojive, and your exact throat dimensions it would duplicate closely.

The bullet seating depth feature of the tool isn't particularly useful except as a relative measurement, but the case shoulder gauge seems to be very close to correct on the two I've played with when compared to a go gauge.

 

[amlevin]

The diameter of the straight bullet hole in the RCBS tool, the ojive of the tool compared to the loaded bullet, and your leade angle add up to the inconsistencies. If the RCBS tool had your exact bullet ojive, and your exact throat dimensions it would duplicate closely.

A fellow I shoot with takes a piece that he's cut off his barrel blank and runs his chamber reamer into it until it just reaches the neck/shoulder junction. He then uses this small "gauge" to check his seating depths. Since he "jams" his bullets he leaves a little of the case neck visible in his "gauge".

Since it's cut from the same barrel blank and reamed with the same reamer, it's as close to same-same as one can get.