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View Full Version : I think I solved my concentricity/runout issues....



Russel Nash
05-29-2017, 03:12 AM
My original thread is here:

http://castboolits.gunloads.com/showthread.php?331117-I-bought-a-concentricity-gauge-WARNING!-J-word-bullets-ahead&highlight=Concentricity

Long story short, I resized my processed brass with an RCBS X sizer die with the decapping mandrel removed.

That got the runout of the empty necks down to like 1 or 1.5 thousandths.

Then I swapped in my regular .223 toolhead into my 650, and loaded them up like normal.

It did this to 30 or so rounds.

I did run into a little hiccup with little copper flakes getting shaved off while seating the 69gr SMK's.

And there was a little bit of runout still at the bullet.

But they seemed to group fine at 100 yards:

http://i603.photobucket.com/albums/tt112/gryphon1994/20170510_173311_zpsffajmysu.jpg

That is 5 shots. The penny is in there for scale.

I will spring for a Lyman M die and a Redding neck bushing die to see if that straightens the necks AND keeps little pieces of copper from getting shaved off the jackets.

I did try some factory Federal XM855 and XM193 ammo. Turns out they have really bad runout too and can't group with a darn either. So I suspect my brass processor didn't know that the surplus ammo he was buying had the same crazy runout at the neck.

HeavyMetal
05-29-2017, 02:25 PM
can't complain about group size, but run out is a huge issue for accuracy.

You might try a 10 degree VLD chamfer tool for the inside case mouths which may resolve the flake issue and seat with less runout.

Another idea is a Lee collet type crimp die for after seating, used gently of course, this may fix the last of your runout or not.

HM

troyboy
05-29-2017, 03:57 PM
Flat base or boattail? My solution for flat base was using Lee's case mouth expander. For the boattails the suggested VLD chamfer tool is ideal. The VLD tool is what I use for all bottleneck case mouth chamfer's