Excessive pressure?

[joshb]

Whew!! Y'all are exhausting, but I do enjoy the forum! And thanks Boyd Allen for the PM... my thread kind of got commandeered!

Hey Jody: Yeah, your thread got side tracked. Sorry about that. I'm no expert. When I fire new brass in a gun, I'm looking for some "clues" as to what my gun likes. Until the brass has expanded to MY chamber, I don't look for specific data. My first firing with a bunch of different loads is done with the bullet jammed "a little" to hold the case against the bolt face so it can expand as much as possible. Watch for pressure signs. I start to fine tune on the second firing. I'm in this process with a .223, right now. Recently, I've gotten some input about neck sizing. If my once fired brass fits in my chamber after I neck size it, I might try that. Lots of "opinions" on what to do. Read as many as you can. You'll figure out who knows what they're talking about. I've tried a bunch of different "theories". I tend to let my gun and groups tell me what works. Good luck! Josh

 

[hunter243sgk]

The above is good advise. I do things different for each of my rifles. Once several years ago i wanted to try fl sizing only. At that time i only had a cheap die that had to small of a mandrel. Accuracy went south fast. It took me awhile to figure it out. And until i did i blamed it on me not nk sizing only!! You live and learn

 

[LCazador]

I believe your problem is caused by "bolt thrust". You have virgin, as in unfired, brass. They are usually somewhere around 5-8 thousandths short of a fired case. When the firing pin hits the primer it drives the case forward till the chamber wall stops the forward motion. As the case fires it "slams" back against the bolt face. This is done hard enough, from the travel, for inertia to cause the primers to slide out of place in the case. This is not excessive pressure but a lot of room in the chamber. Once the case fills the chamber and you size it about 2-3 thousandths, you won't have that problem again.

After reloading for 50 years, I completely agree. Always start with a moderate load and fire form your brass!!Very well said Ben!!!