Loose chamber? 300wm fired brass neck

[ohiohunter]

My fired brass measures 0.339" and I've just started loading using my 0.330 bushing. I'm pretty sure this gives me ~0.002" neck tension. Should my fired brass be that big? Just curious, I haven't looked at any of my other rifles in this regard but I will when I get home.

 

[Scooterbum]

Yes.

 

[Frank in the Laurels]

It's not uncommon to see .006-.009 per side ! It's amazing to me how well factory chamber actually shoot and some aredammmm good shooters for hunting rifles. All that slop/gap is called insurance involvement ! They hain't paying for you to shoot tiny groups !

 

[ohiohunter]

It's not a factory chamber but over all the difference is 0.009" which would be 0.0045 per side.

 

[bigedp51]

My fired brass measures 0.339" and I've just started loading using my 0.330 bushing. I'm pretty sure this gives me ~0.002" neck tension. Should my fired brass be that big? Just curious, I haven't looked at any of my other rifles in this regard but I will when I get home.

Chamber neck diameter .3407 so your have .0017 spring back after firing (.339)

SAAMI cartridge and chamber drawing
http://www.saami.org/pubresources/cc_drawings/Rifle/300 Winchester Magnum.pdf

 

[MagnumManiac]

My fired brass measures 0.339" and I've just started loading using my 07330 bushing. I'm pretty sure this gives me ~0.002" neck tension. Should my fired brass be that big? Just curious, I haven't looked at any of my other rifles in this regard but I will when I get home.

You do not compare going by bushing size, you measure a loaded round, then a fired case.
For example, my 300 ww-super brass measures .334" with a bullet seated, a fired case measures .337", I have .002" springback, my chamber measures .339". My comp rifle has a .335" neck, some brass requires turning, some doesn't.
Hope this clears things up for you.

Cheers.
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