Overall length measurement

[Nate]

I'm getting dangerous! I bought a davidson seating depth gauge look out. my variation in loaded ammo overall length is 0.008. OK so what do these values tell me?? the way i see it i'm pushing two 1.5 degree surfaces together. the barrel leade and the bullet ogive. I figured i would use the avg. value as my starting point for this bullet, What is your procedure/approach on this?? Oh and if you wonder if a 30-284 will shoot, ask the pig i dropped just about in its tracks at ~~150 yards!! Mucho Mucho Thanks

 

[John Kielly]

Nate,

(1) Seating depth checkers are usually set up to take a measurement close to where the ogive of the projectile meets the parallel case body. Your seating plunger addresses the projectile further up. If there is any irregularity in the form of the projectile points this could cause the differences.

(2) If the bases of your cases are out of square, ir if some primers aren't seated below the case base, you won't be measuring apples & apples.

(3) The operator can skew the loaded round on the calipers or apply variable pressure round to round causing variations.

(4) Compressed loads are known to back out projectiles in some circumstances.

John