Fire Forming and Pressure signs

schne3

schne3

New member
I am loading new Lupua .243 brass that is several thousandths smaller than my fire formed chamber size. When I resize the fired brass I go .002 back, just as I have been instructed, but should I be loading the new brass with less powder to reduce my pressure signs on the primer?

Any help or comments would be appreciated.
 
those most likely are not pressure signs, the most likely cause is undersized brass and/or oversized chamber. It happens to me also, I fireform for over a dozen wildcats on a regular basis. I have seen this in hornet based wildcats, 223 based wildcats and 404 jeff wildcats.
In fact I dont use less powder, I use a healthy load to make sure the brass expands to meet the chamber and adjust my sizing dies accordingly.
 
Also depending on whether its an AR or Bolt, I only neck size after fireforming on Bolts, and full-size .001 or .002 for my ARs.
 
If your chamber is shorter there is a couple things you can do. Neck your brass up one caliber and then back to the caliber your using but only far enough to close the bolt. This will give it a false shoulder to head space on. Or seat your bullets to be into the lands, that will hold it back agianst the breach face when you fire it. ( this method will bring the pressure up so be careful).
Good luck Chris
 
Also you don't want to push the shoulders back on the inital fireform. The more resistance you have (to a point) the better. This keeps the brass from stretching and causing a seperated case problem. A light crush fit is good for fireforming. Adam
 
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