HELP - Case length deviations

[thefitter]

Trying to figure out where my case length deviations are coming from.

.308

New Lapua brass

Fire formed twice

Bump shoulder .002

Re size neck .006 in 3 steps

Trim in Giraud Trimmer

Now 10 cases processed EXACTLY the same show these OAL:

2.0080
2.0080
2.0080
2.0080
2.0085
2.0085
2.0105
2.0115
2.0120
2.0120

I know the Giraud Trimmer indexes of the shoulder so I measured all from base to shoulder and they are all the same.

I am using a Forster Bushing Bump die.

I am totally lost. Where are these deviations coming from?

Thanks

I may be able to help. I had the same problem and Doug asked me if there was some slight sticking in the case holder when using. I said there was and he said it was because of using a bushing die and/or neck die. He asked me to send a few empty cases to him and he would machine the case holder out some to accommodate my cases. He did it and now all my trimmed cases are the same or within .001. Give Doug a call or write him. He will fix your problem.

Thanks!! I called today and I'm sending it off.

 

[Leaddog]

Glad to hear it. Your problem is now solved!