Thread: Resizing inconsistency - Am I missing something

Reloading for 6.5 Creedmoor using Redding Match grade Bushing Die and Redding Press

Once fired Hornady brass all measuring 1.561” on my digital calipers. Have set up the full length die to bump shoulder back .002” with a .290 bushing. All case necks are measuring exactly as they should and most cases are coming out at 1.5575-1.559” but I’m getting random cases at 1.555-1.556”??

Process is to lube cases, resize in press then rotate 180deg then press again. I’m measuring each case as I’m a bit obsessive 😂

Have kept those cases that are over sizing aside but I’d like to know if anyone else gets this inconsistency? Is it normal or is there something I’m missing?

Are you trimmimg mate? That's what will give you a consistent OAL.

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I assume you're talking about the shoulder comparator measurement not OAL.

I've been trying to work this out too. On my 6.5x55 I try to size to 1.765" but usually get 1.764-1.766" and a few outliers at 1.767" and 1.763".

I've tried different lubes and techniques, and it seems to be par for the course. From what I've read if you anneal the cases correctly then they should all size the same.

I’ve found the most accurate way to control shoulder bump/ headspace is using the competition shell holder set from Redding,

Originally Posted by Gerardo

Are you trimmimg mate? That's what will give you a consistent OAL.

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Sorry mate I should’ve said I mean base to shoulder not OAL, thanks though!

Originally Posted by Magnetite

I assume you're talking about the shoulder comparator measurement not OAL.

I've been trying to work this out too. On my 6.5x55 I try to size to 1.765" but usually get 1.764-1.766" and a few outliers at 1.767" and 1.763".

I've tried different lubes and techniques, and it seems to be par for the course. From what I've read if you anneal the cases correctly then they should all size the same.

Thanks mate glad it’s not just me 😂 I’m assuming it could also be the degree of accuracy that my calipers can achieve, I’m confident that each case is being sized repeatedly in the same way so hopefully they’re consistent enough to produce results.

Just remember if you measure lots, i.e every case (i've been known to as well) it's not necessarily a bad thing but be prepared for tiny inconsistencies as you describe which can be attributed to many factors. This is not always useful information and sometimes it's best not to get bogged down in the detail and stick to results.

Just remember brass get work hardened with firing and with each firing it'll have more and more springback. One of the main reasons people anneal with a AMP annealer is to get the most consistent anneal, thus the brass will have the same level of springback = consistent neck tension and this is true for shoulder bump as well. You can have the best dies, press etc, but if your brass isn't consistently annealed (or not annealed at all) you will have inconsistency in your sizing process. It might not happen in the start of your brass life but will show itself later after multiple firings.

Just another variable to consider. There are quite a few youtube vids about annealing and sizing consistency

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^ +1

Sometimes I think that a 2 to 3 thou inconsistency in measurements is largely unavoidable. Given the machinery involved and the the measuring devices we use.
I've experienced the same "flyers" with shoulder bump (headspace) and also seating depths. With seating depths you can use the same die in the same press, same brass and same projectile batch, same force on the ram, and still end up with a 1 to 3 thou difference in a batch of ammo.
Maybe these variables are able to be totally eliminated but I've tried to no avail, and have settled for the consistently accurate ammo I produce within the variances.
Thats pretty much all that matters because there are a raft of other variables that come into play once the ammo is in the chamber and the crosshairs are on the meaty brown bit

What I've learnt is measure everything when setting up the dies, bullet seating or whatever the process is and measure until you are happy to begin reloading. The only measurement I take after that is the group size, like others have said thats all that matters.

Originally Posted by Magnetite

I assume you're talking about the shoulder comparator measurement not OAL.

I've been trying to work this out too. On my 6.5x55 I try to size to 1.765" but usually get 1.764-1.766" and a few outliers at 1.767" and 1.763".

I've tried different lubes and techniques, and it seems to be par for the course. From what I've read if you anneal the cases correctly then they should all size the same.

With your 1.767 what was the measurement before sizing.

The only time I get a case discrepancy and it's always oversized is when I forget to clean inside my FLS die before starting. After each use I spray a shot of CRC Longlife into the die. CCR Longlife leaves a coating inside. This along with the lube on the case is enough to upset things but not to degree posted in this thread.

Originally Posted by Magnetite

I assume you're talking about the shoulder comparator measurement not OAL.

I've been trying to work this out too. On my 6.5x55 I try to size to 1.765" but usually get 1.764-1.766" and a few outliers at 1.767" and 1.763".

I've tried different lubes and techniques, and it seems to be par for the course. From what I've read if you anneal the cases correctly then they should all size the same.

With your 1.767 what was the measurement before sizing.

The only time I get a case discrepancy and it's always oversized is when I forget to clean inside my FLS die before starting. After each use I spray a shot of CRC Longlife into the die. CCR Longlife leaves a coating inside. This along with the lube on the case is enough to upset things but not to degree posted in this thread.

Originally Posted by zimmer

With your 1.767 what was the measurement before sizing.

I should probably be a bit clearer.

Fired cases are usually 1.766-1.768"
Zero clearance is 1.767"
I'm aiming for 1.765±0.001".
When sizing I usually get 0.004" of variance, depending on how I have the die set e.g 1.763-1.766 or 1.764-1.767.
Every now and then there will be cases which do strange things, but I've also changed lube recently.

However I haven't measured how much difference the case volume makes to velocity. It maybe inconsequential. I do know it affects bullet jump but In my case the change is irrelevant.

I've never measured my case so can't tell you if it's normal or not.
Set aside the "shorter" cases and load them up as usual and see if there is any real world difference on target.

If you are chasing tiny groups for F Class or Benchrest then maybe worry, otherwise don't sweat it.
It's easy to get caught up getting everything perfect but 9/10 if the loads are performing as they should down range then don't worry about it.