40-65: Learning what I can

[SgtDog0311]

Kurt… Perfect! Thanks. Shooting with a friend today who clued me in about the 12-45-0. I was used to reading that angle the way SAAMI expresses it. Should have caught that one and now I recall TexasMac’s chamber cast in the “Lead” thread where he identifies a 12.75 for the Browning casts he posts.

So, .130 in front of the rim is where the case runs parallel (also as Texas Mac mentioned elsewhere) although the 40-65 cast he posts on page 3 does not appear parallel – looks to the eye more like the taper goes straight from the case all the way to where the base of bullet would be. Maybe that is just optical

And judging from dimensions the Datum line is the business side of the rim. And I see the .070 on the other side as well.

So reamer drawings are just boiler plate straight line representations so reamer manufacturers can plug the numbers in to a standard drawing.