Press for precision seating ?

[big5ifty]

I'd like feedback on what you use to seat your bullets to within 0.001", and to within +- 0.001" for the batch.

Let's not get distracted by what other people use, or what is considered "best", just what you use to achieve that.

In my case, I have a Hornady 50bmg press that I use for seating rifle bullets, and I found over time that an incorrectly setup seating die contributes more to AOL variation than the press.

I've seen this in two calibers so far.

The one seating stem didn't fit the bullet profile properly. When I replaced the seating stem with a VLD seating stem the problem went away, and the other was with a Forster benchrest seater.

With that one I found that being setup incorrectly, the seating operation was being controlled by the spring in the die, and resulted in a rather large variation. After adjusting it, I eliminated that problem.

What do you use for seating consistency ?

[janfred]

I must admit that this always confused me. The only COAL variation that I have measured is due to the uneven tips of open tip match bullets. The worst was Sierra Matchking bullets in .311 and .308, but also visible on Berger and Nosler bullets. Looks crinkle-cut at times.

For piece of mind I made an adaptor for my caliper to measure from the base to ogive. Turns out that the important dimensions varied so little that I could not measure it and I can measure to 0.02mm (0.0008").

 Also, I once purchased a box of Sierra 2156 155gr .308 bullets. I am certain there were 3 different batches in one box as there were 3 distinct bullet base-to-ogive lengths. As you can imagine I no longer use Sierra bullets.

So far I have used Lee, Redding, Hornady and Forster seating dies. Admittedly only in .303b and .308w chamberings. Perhaps the problem is with other cartridges...

[Treeman]

The difference in bullet OAL and base to ogive length is a far more real problem than seater die issues. Seater die issues are fixed or replaced, but the bullet problem is ?
I personally do not feel that the press in any of the known brands itself will vary in seated depth time to time again.

[oafpatroll]

I don't rate my ability to measure COAL accurately and consistently to a thousandth high enough to comment.

[Treeman]

I don't rate my ability to measure COAL accurately and consistently to a thousandth high enough to comment.

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Now here is a honest man!!!!!!!!!!!!!!!!!!!!!!!!!