Seating Question...Pondering


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jwrowland77
June 19, 2013, 12:59 PM
Using the Hornady OAL gauge you find your max OAL, which is where the ogive touches the lands and grooves.

When you go to find the distance from the lands and grooves using a comparator, say the Hornady LNL comparator, it measures to the ogive to give your distance.

A seating die, seats all rifle bullets based off of the ogive.

Is it a safe assumption then, that since most bullets are seated off of the rifle bullets ogive (of course unless you have a really long bullet), and you adjust your die to be a certain distance from the ogive to the lands, that most bullets seated using that seater will give you the same distance to the lands from the ogive and should get the same measurement from case head to bullets ogive when using a comparator?

Was just thinking about this based on where you measure with the comparator tool and where the seating die touches the bullet when seating.....

Thoughts?

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MtnCreek
June 19, 2013, 01:12 PM
The seating stem and comparator are not the exact same size. You'll need a new measurement for each bullet used.

Blue68f100
June 19, 2013, 01:18 PM
^^^^^^^ this

That's why I determine the max OAL for each bullet type/weight/shape..... All will give you a different OAL. Some times the Magazine will be the limiting factor.

jwrowland77
June 19, 2013, 01:23 PM
Oh yeah, I always measure a new OAL for each different bullet, I was just pondering. I normally go by ogive measurement though, since there could be differences in the tip of the bullet that causes OAL to be different. Not by much, but still more than measuring to ogive.

USSR
June 19, 2013, 01:27 PM
In addition to what has been said above, you also have different ogive locations from the very same bullet manufacturer (due to them coming off of different machines) in relation to your seater, so you will get variations in the amount distance between your bullet ogive and the lands of your loaded rounds. Even Sierra MatchKings will vary up to 0.010" in ogive location, so for this reason I never seat bullets for less than 0.010" jump.

Don

GLOOB
June 21, 2013, 04:21 PM
Only in a pipe dream. Your seater plug would have to exactly match the shape of your rifle's throat (and that will slowly change/erode over time, anyway). Each different bullet shape might make first contact with a different point on your rifle's lands/throat, depending on the angle/shape of the ogive.

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