284 Win Brass Prep Question

[jeguia]

I need your help!

My reloaded 284 brass is expanding approximately 2thousandths when I seat a bullet. I’ve never experienced this before. The expansion occurs only at the case mouth (not the entire neck). The expansion is greater than my chamber of .317” so I’m unable to chamber the cartridge. The case mouth measures approximately .318” to .319” and the case neck measures .316”.

Please let me know what you think is happening. In other words, what am I doing wrong?

my brass prep process:
1. Deprime
2. Wet tumble
3. Anneal (AMP annealer)
4. Full length resize shoulder bump of .003”
5. Expand neck to .283”
6. Chamfer & deburr
7. Prime
8. Charge
9. Seat

Thanks!

 

[TylerFromMS]

Prob need to turn. I'd rather get it rechambered to a bigger neck.

 

[jeguia]

Prob need to turn. I'd rather get it rechambered to a bigger neck.

That’s my conclusion as well. Both points. Lol.
I just didn’t know if I was doing something wrong specific to the 284 brass as my experience with 284 is limited.
Thanks for responding!

 

[TylerFromMS]

That’s my conclusion as well. Both points. Lol.
I just didn’t know if I was doing something wrong specific to the 284 brass as my experience with 284 is limited.
Thanks for responding!

I have very little experience with that cartridge, honestly. I only just started playing with one. It's just that is what it sounds like to me.

 

[MattPeetz]

You need to neck turn

 

[KenOath]

Turn necks or open chamber neck to .319”-.320”..

 

[jeguia]

Turn necks or open chamber neck to .319”-.320”..

Thanks!

 

[Steve Blair]

My .284 Shehane (turned necks) is Ø.308" seated in a Ø.313" chamber. I like .005-.006" diametral clearance for 7mm and .308. Turn your necks to .014" wall for Ø.312" seated. That should be ~80% cleanup with Lapua brass.

 

[jeguia]

My .284 Shehane (turned necks) is Ø.308" seated in a Ø.313" chamber. I like .005-.006" diametral clearance for 7mm and .308. Turn your necks to .014" wall for Ø.312" seated. That should be ~80% cleanup with Lapua brass.

Great info. Thanks!

 

[FeMan]

It sounds like you are using Peterson or Norma brass. They are much thicker than Lapua or WW. Trying Lapua or WW brass is an option as well. They should be fine as no-turn in a 0.318 chamber; maybe a light skim to clean them up.

 

[jepp2]

I need your help!

If you aren't set up to turn case necks, you might consider using:
https://djsbrass.com/services
and get the job done right.

 

[jeguia]

It sounds like you are using Peterson or Norma brass. They are much thicker than Lapua or WW. Trying Lapua or WW brass is an option as well. They should be fine as no-turn in a 0.318 chamber; maybe a light skim to clean them up.

This phenomena occurred with both Lapua and Peterson brass. Thanks

 

[Willow]

This phenomena occurred with both Lapua and Peterson brass. Thanks

Peterson will definitely cause you problems then - I specced my reamer with .321 neck to account for the extra thickness in the neck - I'd enquire with your gunsmith if they have a reamer than can widen the neck of the chamber some more if neck turning is a hassle for you.

 

[ronemus]

I always like to turn necks enough to make the thickness uniform around the neck (improves concentricity) and between cases (uniform bullet pull). Even the best brass isn't perfect and will benefit from a light turn. You'll have to decide whether it's worth the effort for your use.