OK, at the risk of repeating what's already been said, here are some things to look for, signs of high pressure which are incontrovertable but NOT GOING TO BLOW YOUR HEAD OFF! (This is important
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You've gotten solid information, please understand that if I'm covering plowed ground it's in the interest of coherence, NOT to rewrite others' posts.
The primary indication that MAX is being reached is something called "casehead expansion." What "casehead expansion" means is that you've reached a pressure level which is permanently deforming the casehead.
In a nutshell, the thin portion of the case, the neck, shoulder and main body of the case, are designed to pop out and seal the chamber against gas leakage. THIS is in fact the main function of the brass case, it's not just a handy receptacle for the powder charge, it's a gasket. The HEAD of the case though IS NOT designed to swell or seal.
True signs of high pressure include:
-Tight bolt lift. Any appreciable drag on the bolt handle indicates that the case has swelled up a little too much.
-A tightening or "click" at the TOP of the bolt lift. Look at the top front corner of the bolt handle where it attaches to the bolt body. This area is called the root of the bolt handle. See a small angled area where the corner has been ground to match an angle in the receiver. This little ramp is called the "primary extraction cam" and it's there do break the case loose it it sticks. Keep it greased. Greased, it will give you accurate "feel."
-Shiny spots or smears on the head of the case. Look at the headstamp, (lettering) if you get hard bolt lift. If there's a small half-moon shiny spot note that it corresponds to the position and size of the ejector hole in the bolt face. The shiny spot is from brass being pushed into the extractor hole, TOO MUCH PRESSURE!!
-Loose primers. Casehead expansion is the result of high pressure gas being metered into the void of the primer pocket. When the pressure gets too high, enough gas enters that it hydraulically expands the primer pocket and consequently the casehead. THIS is a Never-Fail Test. IF your primers are getting loose you are TOO HOT for that brass. You can sometimes change brands of brass and continue to fire at this elevated pressure but I can't in good conscience recommend it at this stage....... in fact, if your primers are getting loose, I recommend you drop 2 grains and write this down as MAX.
Many of the other "pressure signs" like flattened primers and cratered primers can lie to you. Casehead expansion cannot. MEASURING casehead expansion using a caliper or mic can also lie to you, but loose primers are absolutely a sign of too much pressure. As is the mark of the ejector on the casehead.
BTW..... DESTROY THIS BRASS!!! Crimp the neck, wrap masking tape around it with a note, do something to keep from using it. Later you may decide that a case "has one more firing in it" and load it up for a throwaway varmint round but for now, CHUCK IT!!!
Keep scrupulous notes every day, including temp. Powder is temperature sensitive. Elevated temp equals elevated pressure, never forget this.
Remember to GREASE three spots on your bolt very 25rds or so:
-Grease the bolt lugs.
-Grease the primary extraction cam and
-Grease the cocking ramp under the bolt.
When you're working up loads and reloading for effect you will fire A LOT....... and you WILL gall your bolt lugs or one of the cams if you don't form the habit NOW!
Handled correctly reloading is safer than golf, certainly more safe than driving to church Sunday morning.....
Have fun.
Be safe.
Ask lots of questions, the ONLY dumb question is THE ONE YOU DON'T ASK!!!
al
