OAL variance on progressive press

[Monty619]

Hi CalGuns fam! I have a question/concern for all you progressive reloaders out there. I am currently using a RCBS pro2000 auto index press and having a variance in OAL seating depth. Do any of you notice when you load your first round to set your die seating depth to desired OAL, the OAL changes once you run all the stations full? Here is my station specs:

1: sizer(just used to shape the case mouth as the brass is already sized on a Dillon 1200RT trimmer)
2: open
3: powder drop
4: redding seater with micrometer
5: lee FCD

Thanks for the help.

[9mmepiphany]

That's normal on a progressive press.

You should set your desired OAL with all the stations, in use, occupied.

I set OAL a hair long with just the Seating die and then just run cases through and verify that the first completed round is the desired OAL

[Monty619]

That's normal on a progressive press.

You should set your desired OAL with all the stations, in use, occupied.

I set OAL a hair long with just the Seating die and then just run cases through and verify that the first completed round is the desired OAL

Thanks for the reply. My first round was set to 2.260 then once I filled the stations it changed to 2.267

[BigBronco]

After making the assumption that you are reloading bottleneck rifle cartridges. The use of the Dillon RT trimmer indicated this. The OAL varies as the seating stem pushes and seats against the ogive portion though not the exact ogive of the bullet and not the tip.

Most reloaders measure to the COL Base to tip length and not the length from the base to the ogive.

Measure to the ogive length you should find much less variation in length. Most likely if you should you measure your bullets you will find a variation in length as well. Especially with hollow points and soft points.

[9mmepiphany]

Now you know, just set it at 2.253" and see what the first round on you run comes out at. It's just a normal part of tweaking

Edit: I just realized that you are loading rifle bullets. My response was from the viewpoint of handgun loading...and I'm loading FN bullets

As BigBronco posted, you really should be measuring from the base to the ogive

[Monty619]

Ok thanks all for the replies. I'm currently loading ss109 223's