6.5 142gr Sierra coming apart inflight?

C

cord240

Guest
At a recent 600yd match one of my rounds failed to register on the target. The other four rounds impacted normally. My spotter saw the four rounds enter the target but did not see the fifth. I concluded the bullet may have come apart inflight. Thoughts?
 
we have had two come apart at 100 yards in the last month.
 
6.5 142gr Sierra coming apart in flight

cord240 said:
1/8.5 @ 2950fps.
Click to expand...

I've never had that problem with Sierra bullets. Nor have any of my own hand made bullets come apart even when fired through a worn barrel which the shooter only uses to fire form cases. Velocities in the fire forming barrel were in the 3000 fps range.

This condition can happen if the junction point at ogive to shank on the bullet is bigger in diameter. Which happens when the bullet point up die wears thus causing the bullet to be slightly over size at the thin part of the jacket.

This is typical when bullets are made with automatic punch presses, where the core seated jacket is slammed into the point forming die to finish the bullet. This slamming process causes considerable die wear in the point up die. So you end up with a finished bullet slightly larger in diameter up front (the thin part of the jacket walls) than in the rear. So the point up die needs to be replaced.

The bullet maker who makes his bullets by hand does not have this problem.

Hope this helps.

Bob Cauterucio
 
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