Case Sizing Puzzle

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Was over at a friends house today. During my visit he mentioned a sizing problem he was having with a few of his .338 Lapua cartridge cases. He has a batch of 50 cases that had been fired in a Remington factory chamber. The rifle was rebarrel with a new Krieger. All 50 cases were full length sized. Four of these resized cases will not fit his new chamber but the remaining 46 slide in easily. The bolt will not lock up on the 4 offenders.

I checked the cases and found they were approx. .020" too long. Problem solved......or so I thought. Cases were trimmed, run through the FL sizer again.....BUT THEY STILL WILL NOT CHAMBER. I`ve seen this kind of problem before on belted cases that build up a pressure ring in front of the belt which normal FL dies cannot correct however this one is a puzzle - the Lapua case is not belted.

Anyone have thoughts on why these four cases will not chamber.

Regards

Aubrey
 
Annealing the four stubborn ones, then full length resizing may correct the problem. Brass may be springing back, after resizing.
 
I think Lodi may have the answer to this.
If a case is subjected to very high pressures, the web will expand to a larger diameter.
I would try measuring those 4 cases, then measuring a few that fit, and compare diameter.
You will need a vernier micrometer for this to be meaningful.
A FL sizing die will usually not size this part of the case back to factory dimension.
Regards, Eagleye.
 
Thanks guys. An expanded web area is probably the answser. I'll measure the cases on my next visit and give you a full report.

I'm not sure annealling the web area is a good idea as the temperature would be much too difficult to control and probably upset the hardness profile in the remainder of the case. These cases are headed for the garbage can.

Regards

Aubrey
 
Last edited:
Whatever you do...do NOT anneal the body or web of a case.
Neck and shoulder area only!!
You will weaken your brass in the critical web area, and suject yourself to real danger.
Regards, Eagleye.
 
Banished......A body die might help but it would be cheaper to throw the 4 cases away.

No donut comments but I didn't think you had any friends.

G
 
Eagleye said:
Whatever you do...do NOT anneal the body or web of a case.
Neck and shoulder area only!!
You will weaken your brass in the critical web area, and suject yourself to real danger.
Regards, Eagleye.
Click to expand...

Deleted, hit the wrong button and it posted before I was done.
Will continue, correctly.
 
Eagleye said:
Whatever you do...do NOT anneal the body or web of a case.
Neck and shoulder area only!!
You will weaken your brass in the critical web area, and suject yourself to real danger.
Regards, Eagleye.
Click to expand...

I presumed he would know enough about annealing, that I wouldn't have to describe it.
I recently had his exact problem. I acquired a nearly new custom built 243, Styer Mauser action on a Shilen barrel. I had lots of used brass around from when I used 243 rifles quite a bit.
So, trimmed and full length sized my brass. I tried the sized brass in the new chamber. Of course, with the Mauser action you remove the bolt and fit the empty case in the extractor, to eliminate the chance of damage to the neck, by regular feeding of the empty case.
Cases would not go all the way into the custom chamber. Resized, making sure the die hit firmly on the ram.
Still would not chamber.
So, bought a box of factory ammo and they chambered and shot beautifully.
What may be the problem? The old, well worked brass not springing back after sizing came to mind. So I annealed the shoulders of the brass. After another trip through the same RCBS sizing die, they went smoothly into the chamber. And after shooting and again sizing, they again went smoothly into the chamber. Problem solved.
Bottom line is I like a tight chamber, for long brass life, if nothing else.
 
Eagleye said:
Whatever you do...do NOT anneal the body or web of a case.
Neck and shoulder area only!!
You will weaken your brass in the critical web area, and suject yourself to real danger.
Regards, Eagleye.
Click to expand...

Oops, having trouble. Bassically was a double post.
 
Never had such a mix up in attempting a qouoted post. had it there once, but came out double post, eliminated one and they both went.
Still trying.

I presumed he would know enough about annealing, that I wouldn't have to describe it.
I recently had his exact problem. I acquired a nearly new custom built 243, Styer Mauser action on a Shilen barrel. I had lots of used brass around from when I used 243 rifles quite a bit.
So, trimmed and full length sized my brass. I tried the sized brass in the new chamber. Of course, with the Mauser action you remove the bolt and fit the empty case in the extractor, to eliminate damage to the neck, by regular feeding of the empty case.
Cases would not go all the way into the custom chamber. Resized, making sure the ram firmly hit the die. Still wouldn't go into the chamber.
Bought a box of factory ammo and they worked fine.
So why wouldn't my resized ones work?
My well worked old brass springing back after sizing came to mind.
So, annealed the shoulders, put them through the same RCBS sizing die and they went perfectly into the chamber of the custom rifle!
Problem solved.

Edited to say, the mods must be pl aying tricks on me. A post is gone, I rewrite, then both appear. I'm leaving as it is.
 
Web expansion is normal, but it usually settles down after a couple of firings on new brass. Too much expansion is relevant only to the cases and rifle at hand. I'm sure that when these few problem cases are compared to the non-problem cases that the differences are very minor. It's not that there is an issue with the loads or the rifle, it's just a compatibility issue between cases fired in two different chambers.
 
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