Measuring Loaded Rounds

[Flat Land Shooter]

Erik - hope you don't mind me starting this? I noticed people on the 100 yard loading thread were interested same as me.
I coated a bullet and checked the dimension to the lands, then went to the comparator ring and rotated the bullet to scribe a ring.
Then looked at the ring compared to the engraved marks from making contact with the lands. It is very easy to seet the difference.

I'm thinking you use a section from the barrel cut off adapted to a micrometer to measure loaded rounds for seating depth?

Please help us!

 

[stool]

i'm not erik, but i did sleep at a holiday end last night.

it does not matter.....it is a reference point for your dies and your bullet......
just because the comparator measures at a lower or higher point means little...the bullet did not move when u measured its position did it ?
your dies do not typically touch the bullet at the exact dia as YOUR bbl. the comparator does not either...they allow you to pick a number( based on the touching the lands bullet in a case)....
that number can be repeated in your dies..amd now the loads are the same..no matter what the NUMBER is.

 

[Jay Christopherson]

Your method will depend on what your tolerance for variance in the OAL of your loaded rounds is. In my opinion, if you are shooting for < .001" total variance, a caliper/comparator won't cut it. Too much room for error, whether it be in the drift (if using a digital caliper), the measuring technique, or the calipers themselves.

 

[Erik Cortina]

Stool's response is the typical assumption that all bullets are consistent.

The ogive profile in bullets varies greatly, I've seen as much as .020" from the point where the seating stem contacts the bullet to the point where the bullet contacts the lands.

I have a tool that I developed that I'm working on a patent for right not that will "cure" this issue. But in the mean time, you can use a Bob Green caliper tool or a modified insert for the Hornady comparator. The comparator has to be bored so that the comparator will contact the bullet at the same place where the bullet contacts the lands. If you are not measuring at that point, you don't really know where you are at in relation to the lands.

 

[stool]

erik,
what do you do when the throat begins to wear and the dia is no longer consistant??

Stool's response is the typical assumption that all bullets are consistent.

The ogive profile in bullets varies greatly, I've seen as much as .020" from the point where the seating stem contacts the bullet to the point where the bullet contacts the lands.

I have a tool that I developed that I'm working on a patent for right not that will "cure" this issue. But in the mean time, you can use a Bob Green caliper tool or a modified insert for the Hornady comparator. The comparator has to be bored so that the comparator will contact the bullet at the same place where the bullet contacts the lands. If you are not measuring at that point, you don't really know where you are at in relation to the lands.

 

[Erik Cortina]

Stool, all the diameter can do is grow, at which point it will not contact the lands. There will always be a point where the bullet will contact the lands, that's the point where you reference from.

 

[stool]

but the dia of the contact point will change...how do you adjust/compensate for that??

Stool, all the diameter can do is grow, at which point it will not contact the lands. There will always be a point where the bullet will contact the lands, that's the point where you reference from.

 

[Erik Cortina]

but the dia of the contact point will change...how do you adjust/compensate for that??

Stool, all the diameter can do is grow, at which point it will not contact the lands. There will always be a point where the bullet will contact the lands, that's the point where you reference from.

If the diameter of contact point changes it does not matter as long as you reference from the same point.