Neck inner diameter shrinks after wet tumbling and dehydrator drying?

[SuperBruce]

I'm setting up my dies and just finished cleaning (wet tumble with ss pins) and drying (dehydrator) some once-fired hdy 6.5 creed brass (from factory match ammo). While trying to dial in my resizer I checked the neck inner diameter before sizing and found it to be 0.260". At first I was sure this was a problem with my calipers and tried to insert a bullet but it wouldn't fit. I don't have any remaining fired+uncleaned brass to compare against, but I've used the same cases to test seating depths and I'm 99% sure the necks were lose at that point.

Is this a thing, or have I screwed something up along the way?

 

[hitman44]

Ive never been able to get accurate internal neck readings from using calipers.

 

[918v]

How many firings on the cases?

 

[Baron23]

@918v

some once-fired hdy 6.5 creed brass

 

[Tokay444]

Wet tumbling peens over the case mouth. Try rechamfering. I bet a bullet falls in.
Also, you can’t use calipers.

 

[SuperBruce]

Wet tumbling peens over the case mount. Try rechamfering. I bet a bullet falls in.

This is it. Chamferred and as predicted, a bullet fell right in. Thank you.

Now I'm no longer confident I'm using the right bushing for this die. I'm using a .289 bushing and reading .261" inner diameter for 0.003" tension after sizing but if I measure the wall thickness at about 13 to 13.5 thousands and a neck outer diameter of .290" (I presume from 0.001" spring-back), that puts me between 0 to 0.001" neck tension.

Ideally, I'd get a more confident measurement on my neck inner diameter. How are people measuring that accurately? Secondly, perhaps it's a good idea to go down to the .288 and use the expander ball: chances are my neck has some dings on the inside that could use some smoothing. A part of me kind of regrets going with bushing dies.

 

[alamo5000]

I don't know about anyone else but I recently bought a bunch of expander mandrels.

With those you can get your sizing done and all that stuff but then set your neck ID just before bullet seating.

 

[918v]

Wet tumbling peens over the case mount. Try rechamfering. I bet a bullet falls in.
Also, you can’t use calipers.

+1

 

[Tokay444]

I really need to stop using the autocorrect feature on my phone. Case “mount”?

 

[25ring]

I'm setting up my dies and just finished cleaning (wet tumble with ss pins) and drying (dehydrator) some once-fired hdy 6.5 creed brass (from factory match ammo). While trying to dial in my resizer I checked the neck inner diameter before sizing and found it to be 0.260". At first I was sure this was a problem with my calipers and tried to insert a bullet but it wouldn't fit. I don't have any remaining fired+uncleaned brass to compare against, but I've used the same cases to test seating depths and I'm 99% sure the necks were lose at that point.

Is this a thing, or have I screwed something up along the way?

Maybe Woolite and drip dry?---Sorry I couldn't help myself!

 

[Shootin Stuff]

I'm not really sure why you are fixated on the inner neck diameter. Like it's been said above it's not an easy thing to measure accurately. The easy button is to use outside neck diameter.

Yeah, this.

Run brass through your sizer, measure OD.
Seat a bullet, measure OD.
#2 minus #1 is your neck tension, easy peasy.

 

[db2000]

That must be one hell of a dehydrator!

 

[rustyinbend]

How are people measuring that accurately?

Use a ball caliper (like this) to measure the neck walls, and then subtract the average (twice) from the exterior measurement. It's WAY more accurate than trying to use standard calipers on the inside of a case neck.

 

[SuperBruce]

You can get fired brass neck diameter, resized neck diameter, and loaded neck diameter and it'll tell you everything you need to know.

Already did it and you're right: it's much easier. I ended up following this video here which is exactly the pattern you suggest. My OD with a bullet seated is .292", and using the .288" bushing I get a OD of .2890" to .2895" after sizing for a neck tension of 2.5 to 3 thousands.

Thanks for the help everyone.