Once Fired Formed Case Size Inconsistent

[Doug308]

New rifle, Ruger American Hunter 6.5cm, this rifle has a tight chamber, but what is odd is the once fired brass will measure differently by up to 5 thousandths, im using a Widden gunworks case gauge tool.

Any thoughts ?

 

[Supersubes]

What dimension are you measuring, headspace?

 

[whatsupdoc]

You measuring the fired cases with the primer in the case?

 

[Doug308]

What dimension are you measuring, headspace?

Yes

 

[Doug308]

You measuring the fired cases with the primer in the case?

Yes

 

[308sako]

Decapitated a few of the extremes without sizing the case and try again...

 

[308sako]

Or just decap

 

[Doug308]

Rifle shoots great, I was pleasantly surprised, however extraction is a little difficult, fired case sticks, happens with several brands of ammo.

 

[Doug308]

Decapitated a few of the extremes without sizing the case and try again...

Will do

 

[whatsupdoc]

The primers tend to protrude after firing, remove them all and recheck.

 

[918v]

Or if you don’t have a decaping die, just re-seat them with a priming tool.

 

[TX_Diver]

I know this thread is a few months old but I'm seeing the same inconsistencies as the OP and am curious how to proceed with setting up my FL sizing die to bump the shoulder back .002...

1x fired brass out of the same Tikka t3x Lite. All pieces measured w/ a hornady comparator over about 5 minutes. All brass was de-primed w/ a universal Lee depriming die.
5 pieces of PMC Brass - 1.453 to 1.459 (most 1.45-1.49)
3 pieces of FC brass - 1.4565 to 1.4595
1 piece win bras - 1.4575

Does ambient temp at time of firing make a difference? Fired in 2 different sessions. 25 degrees for one and probably 35 for the other. Not enough that I would've expected to see much difference. Maybe some ammo was pulled out of the house and fired quicker while other rounds were outside with me longer?

I have more brass I could check but those were the first 9 I pulled from the bag. I can also shoot a bit more at the house to experiment.

 

[PinesAndProjectiles]

I know this thread is a few months old but I'm seeing the same inconsistencies as the OP and am curious how to proceed with setting up my FL sizing die to bump the shoulder back .002...

1x fired brass out of the same Tikka t3x Lite. All pieces measured w/ a hornady comparator over about 5 minutes. All brass was de-primed w/ a universal Lee depriming die.
5 pieces of PMC Brass - 1.453 to 1.459 (most 1.45-1.49)
3 pieces of FC brass - 1.4565 to 1.4595
1 piece win bras - 1.4575

Does ambient temp at time of firing make a difference? Fired in 2 different sessions. 25 degrees for one and probably 35 for the other. Not enough that I would've expected to see much difference. Maybe some ammo was pulled out of the house and fired quicker while other rounds were outside with me longer?

I have more brass I could check but those were the first 9 I pulled from the bag. I can also shoot a bit more at the house to experiment.

It is possible that the brass hasn't fully expanded to fit your chamber yet.

You could neck size some rounds, fire them again and then measure. This will tell you if that's the problem or not.

 

[DMP]

I have been firing new cases three times before I feel they are fully formed. I could be wrong.

 

[orkan]

I have been firing new cases three times before I feel they are fully formed. I could be wrong.

This is solid advice. It takes at least 3 firings, no matter how hot the load, to have the cases be representative of the chamber. Generally not a good idea to setup a sizing die for shoulder bump with once or even twice fired brass.

 

[KeithStone]

Yeah I agree it’s not fully formed yet. Had some once fired Winchester brass I loaded this weekend inconsistent by a few thou and wouldn’t bump the shoulder even with die touching shell holder. Hornady twice fired very consistently able to bump the shoulder back 2 thou with die 1-16 turn off shell holder.

 

[TX_Diver]

That was kinda my thinking on how to proceed.

Check how the longest ones chamber, back off from there and rock on. I have a bunch of brass from another rifle too that I want to load for this one. I figured I'd setup the sizing die to take .002 off of the longest piece fired in this rifle and just rock on from there. Maybe I'll mark a few pieces that measure the same and keep one/shoot one just for comparisons sake.

I do have a depriming die to de-prime without sizing, I don't have a neck sizing die. For .223 I'm just using a plain old RCBS sizing die so I want to get it setup once then size all the brass. I'm shooting paper, steel, and coyotes off my back porch, not comps so in reality it will be plenty good for me.

Trying not to go to far down the rabbit hole but also somewhat enjoy geeking out on this stuff so trying to find a balance there haha.

 

[Kire44]

This is solid advice. It takes at least 3 firings, no matter how hot the load, to have the cases be representative of the chamber. Generally not a good idea to setup a sizing die for shoulder bump with once or even twice fired brass.

I am another new reloader here with the same problem... I can't get my once fired, inconsistent, 6.5x55 brass bumped back 2 thousands even with quite a bit of cam over. Should I just use the FL die to reset the body without bumping back the shoulder the first couple of firings? And possibly trim the cases for consistency? Thanks for all help!

 

[spife7980]

I am another new reloader here with the same problem... I can't get my once fired, inconsistent, 6.5x55 brass bumped back 2 thousands even with quite a bit of cam over. Should I just use the FL die to reset the body without bumping back the shoulder the first couple of firings? And possibly trim the cases for consistency? Thanks for all help!

First thing first: Are they all the same brand and lot?
I would reload just a few and fire them and see if they grow anymore.

 

[Kire44]

First thing first: Are they all the same brand and lot?
I would reload just a few and fire them and see if they grow anymore.

All Norma, could be different batches though. There is no need then to start grinding down the die or shellholder to push back the sholder? So just use the FL die without setting the shoulder back? Thansks for any help!

 

[spife7980]

All Norma, could be different batches though. There is no need then to start grinding down the die or shellholder to push back the sholder? So just use the FL die without setting the shoulder back? Thansks for any help!

I wouldn’t say that yet necessarily in regards to grinding.
If you do a few cases as is and they still chamber easy then the case hasn’t yet fully grown to fill the chamber, you might not have an issue once they have fully grown.
If you can feel that the case is impeding on the chamber as is with the current die settings then yes, you will need to file the die or shell holder down to accommodate.