7mm STW case problem?

[Fred Ea]

My brother was fire forming brass and lapping the barrel in his 7stw this afternoon and he had a case separate on him and another case that was suspicious. He loaded up some rounds to Lap the barrel and loaded so new brass that had not been fired yet and had a complete head separation and two more that had blown out to .524 above the belt, so he stopped shooting. They were loaded with a light load- 68.0gr. Of IMR7828- 140gr. Bullets. Would this be due to the load being too light, excessive head space, or a over sized chamber? The barrel is the factory Remington barrel on a model 700, he bought the gun new and took it straight to the gunsmith to have rechambered, never fired the gun before having rechambered. Anybody have any ideas what the problem may be? Any words of experience would be appreciated, haven't had this type of problem before.
FElightbulb

 

[lloydsmale]

I guess im confused. What brass are you FIREFORMING into 7stw. What caliber brass is it? Is it new brass? Most case head seperations are due to brass flowing toward the neck after mulitple firings. things is with most magums ive loaded through the years is that the primer pockets usually give out before they even come close to seperation at the base. If its new brass id guess that excessive headspace is your problem. cant you measure your brass after firing it and compare the measurement between the rim and the start of the neck on them and a piece of brand new stw brass to see if your shoulders are being blown foward excessively. Even on a gun with a bit of excessive headspace you can get by by backing off on your sizing or neck sizing the brass. Ive got a #1 in 2506 thats has a bit of excessive headspace. If i used once fired brass that was fired in a tighter gun it stretches enough even on the first firing that i get a shinny ring around the base and seldom get more the two firings without it comming close to seperation. What I do with it is buy new brass and shoot it first with a starting load and then neck size. If it gets to the point after a few firings that it doesnt want to chamber easily i then will full lenght size but make sure i ajust my dies so i dont bump the shoulder back. Many shooters of mag rifles still use the old school thought of it headspacing on the belt. this will shorten the brass life substantialy. Size your brass to fit your chamber and youll get much better brass life.

 

[Fred Ea]

I should have been more specific, he was forming new 7stw brass to the chamber of his rifle chambered for 7stw. What in don't understand is why the casing above the belt is blown out from .513 before being fired to .524. One case completely separated.
To me it looks like an oversized chamber. He called our gunsmith today and he said the same and that probably came from the factory that way.
Thanks Remington, just what he wanted to do is drop another $700 in the rifle and it is brand new. That's the way to take pride I your work, must have been payday and Friday at 4:45pm
FE

 

[lloydsmale]

Ive heard lately that remington has had a rash of guns with out of spec and out of round chamber lately. Seems there quality control has been slipping a bit as of late. I havent heard of any 7stw that have had this problem though. To be honest most of my remingtons have chambers cut almost to tight if anything.

I should have been more specific, he was forming new 7stw brass to the chamber of his rifle chambered for 7stw. What in don't understand is why the casing above the belt is blown out from .513 before being fired to .524. One case completely separated.
To me it looks like an oversized chamber. He called our gunsmith today and he said the same and that probably came from the factory that way.
Thanks Remington, just what he wanted to do is drop another $700 in the rifle and it is brand new. That's the way to take pride I your work, must have been payday and Friday at 4:45pm
FE

 

[Nimrod]

The barrel is the factory Remington barrel on a model 700, he bought the gun new and took it straight to the gunsmith to have rechambered, never fired the gun before having rechambered. Anybody have any ideas what the problem may be? Any words of experience would be appreciated, haven't had this type of problem before.
FElightbulb

Sounds to me like the "gunsmith" screwed it up doing the rechamber. Why is he fire lapping a new barrel?

Bob

 

[Fred Ea]

Sounds to me like the "gunsmith" screwed it up doing the rechamber. Why is he fire lapping a new barrel?

Bob

Just like a frying pan you cook bacon in, bacon don't taste right until the pan is seasoned. In the last 20 or so years, I have noticed the Remington factory barrels do better and don't build up as much copper in the lands and grooves if the barrels are seasoned with 20 to 30 oily rounds when they are new. Just my experience, may be a mythe, but it seems to work to "smooth" the barrel and it's fun to have any excuse to shoot a gun.
FE

 

[Fred Ea]

Ive heard lately that remington has had a rash of guns with out of spec and out of round chamber lately. Seems there quality control has been slipping a bit as of late. I havent heard of any 7stw that have had this problem though. To be honest most of my remingtons have chambers cut almost to tight if anything.

Our gunsmith said that he has had more problems with Remington barrels with oversized chambers than any other factory rifles he works with. He said that Remington barrels have kept food on his table for a long time, just unfortunate it happened to my brother, I told him it could have very well have been my rifle instead of his. It is man made stuff, but you would think they would take a little more pride in their work. I wonder why the foreign jobs have got their foot in the door.