COAL variance in-between each press throw.

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savage M110 BAS

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What kind of variance are you getting with your reloading press/die combination?
My Lyman single stage press paired up with my Redding die yield roughly 0.15 variance from round to round.

This is causing me to adjust the seating depth for each bullet so I get consistent COAL.

It takes roughly 5 thrown of my press per bullet, slowly adjusting for seating depth to get each round just right.

Will something like a competition die get me repeatable seating depths with only one throw of my press?

Any help would be greatly appreciated.
 
Minute differences in COAL are usually due to slightly different dimensions of the actual projectiles (don't believe me, measure a few bullets). Leaving the die as is will give you consistent seating depth. Doing what you describe will actually cause differences in the seating depth and distance from the bullet to the lands.
 
I get this with my progressive. An empty shell plate will seat deeper than when each station is full. I'll do 50. Check each one and re-do if necessary.
 
When you adjust each round you are more than likely changing the seating depth for each round and causing yourself more grief. You cannot take accurate measurements of seating depth from the coal. The meplat or tip of each bullet, eventhough it may look the same, is not the same. Especially if you are dealing with hollow point match bullets like matchkings or bergers. You need to be taking your seating depth measurements off of the ogive of the bullet. That's the curved part that engages into the lands and grooves. There are a couple of tools used to get this. Rcbs makes small gauges called precision mics that will not only measure your seating depth to the ogive but will also accurately measure how much you've bumped your shoulder dimensions back. The other way is with a caliper and a hornady seating depth gauge. It hooks onto your caliper and measures from the base of the casing to the ogive to give you a depth.
If you try to measure off the tip of the casing you will get inconsistent ammo AND you'll drive yourself nuts trying to make everything equal.
 
It is definitely innacurate to measure COAL from the base of the case to the tip of the bullet. After many frustrating loading sessions, I bought a Hornady seating depth guage. My RCBS press and dies are consistently giving me within .0005" on my seating depth. I found that if there is any more than that, its usually because my primer is sitting very slightly above the base of the case and it throws off my measurement.

I don't think a match seating die will give you any better consistency in depth, but likely less runout on the bullet in the case. However, I don't have one, so I can't really say for sure.
 
Get yourself one of the Hex-Nut comparators from Sinclair International for $20USD. The one I have does everything I need including 22 Caliber (.223-.224), 243/6 mm (.243), 25 Caliber (.257), 264/6.5 mm (.264), 284/7 mm (.284), 30 Caliber (.308).
 
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