Chamber Out Of Spec ?

[Ought6]

May be a dumb question but I have to ask . What could cause the mouth of my once fired cases to have a larger diameter than they used to from the same rifle . I'm not a reloader so I didn't know what could be going on so I found an old box of spent brass from the same rifle and they for sure have smaller diameter case mouths . I cant hardly insert the bullet form an unfired round into an older case but on the more recent ones I can easily insert the bullet loosely . Is something out of spec with my rifles' chamber ? Thanks

 

[MudRunner2005]

Most likely the older brass is higher-quality stuff than the new stuff you're shooting. Or the alloy contents are different, and the new brass doesn't have as much spring-back as the old stuff.

Are they the same brand of brass?

 

[Ought6]

Yes the most recent fired cases are opened more than the older ones

 

[Ought6]

Yes they are same brand and probably same lot

 

[AZShooter]

Probably same lot? My guess is different neck wall thickness with more recently fired brass being thinner. Did you measure neck wall thicknesses?

 

[Rich Coyle]

If you fired them multiple times, it's time to anneal.

 

[243winxb]

Is something out of spec with my rifles' chamber ?

No.
Measuring fired brass is not a good test.

 

[Ought6]

All the brass is once fired brass from Hornady factory ammo that was purchased at the same time and same place . Three boxes to be exact . That's why I said it was probably from the same lot or batch or whatever . The spent cases that were recently fired definitely have larger mouths than the ones that were fired last year or the year before that because I compared them with each other .

 

[MudRunner2005]

If you still have the boxes, then they should have a lot # on them. You can compare those to be 100% sure they are the same lot. Sometimes ammo gets all mixed together on the shelves at stores, and you could have one lot number that was made years ago, but the box still looks the same, and they use the same bullet.

 

[Canhunter35]

Your chamber doesn't change in diameter from 3 boxes of shells...and does it matter? Don't measure them.

 

[243winxb]

I found an old box of spent brass from the same rifle and they for sure have smaller diameter case mouths .

Brass always want to return to its original location. Over time the mouth will get smaller in diameter. This is when comparing just fired to old brass.

It is not something you need to worry about.

Does the boxes have the same lot number on them? If different lots of ammo, different lots of powders may have been used. Resulting in different pressure on firing, but same bullet velocity.