OAL case measuring tool

[spudgun]

Well since we are snowed in I had noting to do so I made a OAL case tool.
Took a .308 win and 6.5 CM. Drilled out the primer pockets to except a 7/32 brass tube. Soldered them on both ends of the tube.
Took a 3/16 solid brass rod and cut longer than the tool.
Put a slight bend in the brass tube to create enough friction to keep the brass rod from easily moving when pulling the case out of the chamber.

Now i just insert a bullet into the case and insert into the chamber and push it forward with he rod. once the bullet is seated as far as it can go in the chamber I can remove and measure the OAL.

Seems to work ok for me.

 

[chromatica]

This will work as long as your cartridge headspace matches the chamber headspace exactly. The position of the bolthead is missing from this setup.

 

[spudgun]

This will work as long as your cartridge headspace matches the chamber headspace exactly. The position of the bolthead is missing from this setup.

yes, I'll give you that but these are fire formed cases.

The measurement I am looking for is from the neck to the ogive of the bullet.

Even if you use the Hornady OAL case tool it works on this same principal.

 

[Heavy Metal 1]

You do not need to bend the brass rod or the carrier tube. One can drill a very small hole in the carrier tube and screw in a very small screw to hold the rod in place. Similar to the set screw of the Hornady unit.

 

[dolek]

Handy rig,time well spent on a winter day.

 

[spudgun]

You do not need to bend the brass rod or the carrier tube. One can drill a very small hole in the carrier tube and screw in a very small screw to hold the rod in place. Similar to the set screw of the Hornady unit.

yeah, thought of that too, but the slight bend worked for me. Since I can use the other case as a handle to help pull out the case in the chamber I don't even need to touch the rod or brass tube to get it out.

 

[savagedasher]

A rod down the front end of bore with two thumb stops works great

 

[Mad_Charlie]

This will work as long as your cartridge headspace matches the chamber headspace exactly. The position of the bolthead is missing from this setup.

Or do the math...

 

[Zero333]

Or do the math...

Anyways you look at it, with a fireformed case the measurement will be withing 0.0015" when compensating for the brass shrinking after being fired.

 

[Tpetrat]

This will work as long as your cartridge headspace matches the chamber headspace exactly. The position of the bolthead is missing from this setup.

I've never understood this. How is Oal different regarding which brass you use. I currently use to horandy tool and was told that it was more accurate if I made a fireformed case and used that. But I dont understand what would change? if so can i simply measure the length of the horandy case and subtract it from my fireformed case?

Sorry to add to your thread but it sort of relates

 

[Richard Coody]

well for me as long as you can get repeatable measurements it doesn't matter what method you use. that measurement is nothing but a datum to begin seating depth test with.

some may jam the bullet into the lands for their measurement. i do. i find my most repeatable measurements that way.

some may push the bullet in till they think they feel the lands. as long as it is repeatable it works for me.

some stop with first resistance. if it is repeatable its fine. bullet has probably just entered the throat.

then there are those who use the stripped bolt method. again if it is repeatable fine. always have wondered if they are in the throat, bullet in the forcing cone or actually almost contacting the lands when that bolt will still freely fall. probably different with different chambers.

anyway it.really is just a.datum for a starting point for seating depth test.