OAL Sanity Check


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leadchucker
January 21, 2013, 01:34 PM
I'm trying to figure up a starting point for loading with Precision Delta 9mm 124 gr FMJ RN bullets. The load data for a Sierra 125gr FMJ RN 8120, in the Hodgdon manual would seem to be a fairly close match.

The Hodgdon data calls for an OAL of 1.090 for the Sierra bullet. According to the Sierra data, the Sierra bullet is .581 long. That's about .020 shorter than the Precision Delta bullet. So I'm looking at an OAL of 1.110, but that OAL puts my Precision Delta bullet in so deep it's past its ogive.

That also figures out to be a seating depth of about .250. That's kinda deep ain't it?

So I figure I'm going to have to increase OAL. Right? What I'm wondering is what is a good average minimum seating depth for a 9mm bullet? (assuming no issues with magazine fit/feeding/plunk test.)

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rcmodel
January 21, 2013, 01:51 PM
Figure out where the bullet shank ends and the ogive begins with your calipers.

And seat to there.

Probably be around 1.150" - 1.155" or so.
Then do the plunk test, and seat a little shorter still if necessary to miss the rifling leade.

rc

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