284 Win Chamber help

[jbpmidas]

Reamer is marked 284 Win from PTG. Fired brass measures .4905 at shoulder and .500 at base. My sizer sizes back to .4745.

I’m thinking the reamer is mismarked, but I can’t find what chamber it actually is.

Any help is appreciated!

 

[Zero333]

Only thing you can do right now is take the sizing die and 3 pieces of fired brass and send it to Whidden gunworks or Hornady or wherever and they'll hone it proper.

 

[Steve Blair]

Reamer is marked 284 Win from PTG. Fired brass measures .4905 at shoulder and .500 at base. My sizer sizes back to .4745.

I’m thinking the reamer is mismarked, but I can’t find what chamber it actually is.

Any help is appreciated!

It is likely a .284 Shehane reamer. I'm not at home or I would post my reamer print.

 

[jbpmidas]

The Shehane prints I found were .4845.

 

[Steve Blair]

The Shehane prints I found were .4845.

They are usually Ø.485" but it would not surprise to see a chamber with .010" total body taper (Ø.490").

 

[jbpmidas]

Would that little body taper cause extraction issues?

 

[Steve Blair]

Shouldn't in a bolt gun. The case contracts ~.001" after firing.

 

[Steve Blair]

Here's my Shehane reamer, Ø.485.

 

[jbpmidas]

Sounds like a Shehane sizer would work my brass less.

 

[Steve Blair]

It would, but since you have a non-standard chamber, even for a Shehane, Zero333's suggestion is the best course. John Widden makes fine dies and you'll have one that fits your cases well.

 

[jbpmidas]

I have several sets of his dies. I’ll do some more testing before I decide to send the die back to him. Thanks for the help!