Strange fired brass chambering

[Knight]

After a day at the range testing new loadings for my 308 I was surprised of my findings. Some of my fired brass was able to be chambered with smooth bolt closing while other fired brass had to be FL sized in order for bolt closing. I never had experienced this before. All this brass is Lapua 308 brass... The time before at the range all the brass had to be fl sized before the bolt would close. Has anyone experienced this strange issue ...

 

[Mike D Texas]

My guess is the ones that were hard to chamber were overpressure.

 

[Knight]

I have found in all my once fired brass I was unable to chamber it until it was FL resized again or shoulder bumped.

 

[Mike D Texas]

I have found in all my once fired brass I was unable to chamber it until it was FL resized again or shoulder bumped.

That should not be the case unless they are overpressure. I used to neck size only and could fire the same case several times before needing to bump the shoulder and resize the base.

 

[Knight]

It's possible some of these fired cartridges have grown to exceed trim length. I did have to trim some but isn't the norm that once fired brass would not allow a bolt closing because of either shoulder expansion or neck growth...

 

[ShtrRdy]

I usually don't try to chamber fired brass so I don't have a good idea of what is normal.

 

[Knight]

I just went over about 40 rds of fired brass and I did have to resize some once again.
.I believe the culprit maybe was spring back oh well, I will not wash them again or feed them after midnight for sure....thanks for you input..

 

[RegionRat]

Just a few less obvious thoughts in case they help.

Always be careful shooting in wet or foggy conditions. Getting condensation on the rounds or in the chamber can cause strange behavior.

Always make sure the chamber is deliberately cleaned as a sperate step to cleaning the barrel. It is too easy to find problems when folks don't realize the gap between the bore guide and the barrel allows cleaners and lubes to accumulate and cause trouble.

 

[Lefty7mmstw]

chamber slightly out of round?

 

[antelopedundee]

Just a few less obvious thoughts in case they help.

Always be careful shooting in wet or foggy conditions. Getting condensation on the rounds or in the chamber can cause strange behavior.

Always make sure the chamber is deliberately cleaned as a sperate step to cleaning the barrel. It is too easy to find problems when folks don't realize the gap between the bore guide and the barrel allows cleaners and lubes to accumulate and cause trouble.

A .410 or 20 gauge shotgun bore mop makes a pretty good chamber cleaner, esp. if you put a bit of Ronsonol on it. Also a clean patch in one of those needle eye jags is good for cleaning the neck and throat and also the lug recesses, esp. if you use lube on your bolt lugs. Here is and old pic, not real great, but you can see the point.

 

[Knight]

Thanks for the info much appreciated.

 

[antelopedundee]

After a day at the range testing new loadings for my 308 I was surprised of my findings. Some of my fired brass was able to be chambered with smooth bolt closing while other fired brass had to be FL sized in order for bolt closing. I never had experienced this before. All this brass is Lapua 308 brass... The time before at the range all the brass had to be fl sized before the bolt would close. Has anyone experienced this strange issue ...

Did you mic or check case head diameter in the web area with a caliper and compare primer flatness of the cases that wouldn't chamber? Seems like over-pressure might be in play. I don't recall not being able to rechamber a fired case. If I can rechamber a fired case it tells me that I don't need to full length resize. For hunting ammo it might be a good idea to set aside 20 cases and ALWAYS resize them since the last thing a person needs when hunting is ammo that's useless.

 

[Knight]

I haven't checked the case head Dia but I'm going to check all dementions at the next firing. It's possible it was spring back. Thanks

 

[Mikecr]

I believe the culprit maybe was spring back oh well,

You're right, in that the variance is due to brass character.
And the more you size it, the more character you'll see.