COAL Variations Using A 550

[MichiganShootist]

I have been reloading with my 550 for three years and noticed yesterday that I seem to be getting a lot more variation in overall bullet length than I have experienced in the past.

I reload only .45 ACP and use Zero 230 grain FMJs with very carefully cleaned and inspected mixed head stamp brass.

When set at a length of 1.25.... I was getting ranges anywhere from 1.256 to 1.242... I called Dillon and was basically told that it was so small a variation that it made no difference.... and that it was probably caused by the mixed brass.

But----When I re-ran the "longer" bullets through the seating die... they would then drop to the 1.25 setting.

How about some feed back on the topic?? In the past the range was generally more like 1.252 - 1.248..... with 90% being at 1.25 using the same brass.

[HSMITH]

Well, first thing I would do is check the OAL with a comparator, see what the true variation really is. Could be that the bullet ogive is a little more inconsistent than it was.

Second, segregate the ammo and take a batch of long ones and a batch of short ones to the range. Chrono them and group shoot them from a good rest. Then do the same for a batch mixed with long and short. What happened?

[dillon]

When you are only using the bullet seating die, you put less upward pressure on the toolhead than when you are actually reloading in a progressive manner. You need to set the size die with a fired case in station one, to achieve consistant upward pressure on the toolhead. This maintains consistancy on the mechanical side of things, but this only counts for about .002"-.005" of variation at most. On non-flat pointed projectiles, the projectile is seated from a distance where the bullet seat stem contacts a given diameter on the ogive downward a given distance. But due to variations between one projectile to the next, where the contact diameter is on the projectile can vary up to .025" for most pistol projectiles.

HSSMITH is correct. You can use a bullet comparitor to check the variation in a batch of projectiles. Most shooters don't worry about it. In my personal experience it won't make a difference out to 50 yards or so.

[MichiganShootist]

Thanks for the input.

I knew about having a case in stage one... there was always one there. I'd run 50 - 75 cartridges then just start measuring them with my Dillon micrometer... that's when I found out about the varience range.

If I understand you...... the contact point can vary up to .025.....and my variation range was .014.... so I should be happy???

I was just concerned that the seating die was wearing out or that it was "out of round". I load nothing but round nose 230 grain FMJs and have probably run 30K through the machine since it was delivered..... and I have 10 K Zeros sitting next to it at this time.

I was just worried that something was going wrong because I checked a box of ammo left over from last year and the "spread" was so much smaller I gave me cause for concern.

[dillon]

.014" is well within tolerances for these projectiles.