Help with factory overpressure signs

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fatrack

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A friend came over to work up some loads for his Thompson Center 7mm Rem. mag. and after looking over his once fired (from this rifle) factory loaded brass it looks like some high pressure. Totally flatted primers, loose primer pockets and the brass needs to be trimmed lots. He says this rifle originally had a 22-250 barrel on it and he put a 7mm on it. I did notice it is hard to close the action. I don't think you can really headspace these rifles so anyone have any insight. I was thinking too much headspace? Can excess headspace cause these signs?
 
Yup, it is Federal ammo so that might be part of the problem. These primers are so flatted that they have flowed into and filled the entire primer pocket.
 
If it is a custom barrel, perhaps the throat was cut short and is too short for the factory ammunition used. This would result in the bullet jamming in the lands (making for hard closure?) and would increase pressure.
 
The barrel is a Thompson barrel and I guess I could check the chamber depth to see if a factory round will touch the lands. Maynard, why would Federal brass cause flattened primers?
 
Federal brass is very soft. Handloaders usually stay away from it whenever possible. With Federal factory loads I have had primers pop right out of a fired case when ejecting from a semi.
 
Federal primer are very soft also,they tend to flatten even in midrange loads. TC chambers are cut kinda funny sometimes,if you want to check to see if the bullet is hitting the leads black the bullet with a magic marker,chamber it then remove the rd. and check to see if the bullet is touching the leads if not I would suspect its the ammo.
 
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