bonanza reloading tool?????

[577/450]

picked this up in a junk box at auction what is it?

 

[vagrantviking]

Powder measure. Missing the reservoir.

 

[577/450]

Powder measure. Missing the reservoir.

Does it look like a large funnel?

 

[rosebute]

Bonanza powder measure. I had ( have?) one but found it to be a hassle to use.

 

[diopter]

Left side of photo:

These days sold as:
https://www.midwayusa.com/product/630145/forster-bench-rest-powder-measure

Manual:
http://reloading.davidshangout.com/wp-content/uploads/2015/04/Forster-Bench-Rest-Powder-Measure.pdf

How to read a vernier scale;
https://www.youtube.com/watch?v=Vz40xmrdhyY