Franklin Arsenal case prep center ???s

I have 2 of these. Ones set up for .223. The other one I adjust for whatever caliber brass I’m trimming.

Today was frustrating!!! Hoping someone opens an “oh crap” moment for me.

I sized and primed 50 pieces of 22-250 brass on my Rockchucker. Then I started trimming. The “trim center” was set for 22-250 since that’s the last thing I did before I pushed it aside 4 months ago to tie flies.

First couple were pretty damn close to the 1.902 I wanted. Then they started to wander, long. I made a couple adjustments trying to get back to 1.902. I ended up cutting some short, like 1.889. After farting with it for 20-30 minutes, 10-12 cases, I tore it apart and used a toothbrush to clean every single chip of brass outta it.

Once I got it back at close to 1.902, I would get one every so often that was completely trimmed, but was at 1.9055, or around there.

I finally resized one. It shrank from 1.905 to 1.9025.

I ended up doing that to 5-6.

I ended up with 43 out of 50 that weee 1.902-1.9035. The other 7 are short.

So, I guess I’m getting some brass “spring back?” Is this normal?

I’m sizing in a Rockchucker with nearly new RCBS dies. Nearly new=25 yo but less tha 700 rounds sized through it. I’m priming with the same tool. I hold the case fully locked down while I get the primer. The case sits in the fully full length sized mode for 10 seconds. If nothing else, I always strive for consistency.

This is 2-3X fired Win brass.

Is it the trimmer?

I’m guessing I’ll hear about annealing.

Or am I being too particular??? I think accepting 1.902-1.9035 was being lenient enough?

N555 said:

Maybe the case trimmer has had it?

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Pretty new. Maybe 5,000 .224 cases total. I’m thinking the case diameter makes a difference. If I trimmed a .284 case, I would be using virgin cutting blade.

Hugger-4641 said:

Are you holding it straight when you de-burr the inside of the case?

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That’s something I’ll have to look at closer. But I only debur inside and out for an 8 count, minimal pressure. Less doesn’t always allow the projectile to always slide in smoothly. I don’t think I’m fully cutting through the case, inside or out.

But that’s something I have wondered about. Seems straight. But I’m sitting down and my eyes are lower than the case so it’s something I’ll need to check out.